The Composites

Yes, it’s a bit absurd to attempt an introduction to Asteraceae in the Apalachicola Flora; nobody would accuse me of being expert with this group of plants. But introducing this family for people interested in the Flora of our region requires some explanation that may not be readily available otherwise. So let’s dive into the topic.

This is a large and diverse group of plants, nearly rivaling the Orchids in numbers of species globally (over 30,000 species of Asteraceae worldwide) and surpassing Orchids in ubiquity. You’ll encounter these plants commonly in our region, with around 300 species recorded native and ruderal to the several counties around the Apalachicola River, in addition to the many exotics planted in area gardens,

Nomenclature and Collective Nouns: Throughout discussion, I’ll refer to the Compositae and Asteraceae in a casually interchangeable way, allowing me to reference the family as an entity without so repeatedly using the same term. It’s not a stretch; these are perfect synonyms. Generally, there’s a single family name established through Rules of Nomenclature, following the “type” concept. Thus Asteraceae is based on the genus Aster. But another name for the family, Compositae, has been so widely utilized that the “Rules” traditionally have recognized this as an acceptable alternative (as is true for several other families, i.e. the Graminae, Cruciferae, Leguminosae, Guttiferae, Umbelliferae, Palmae, Leguminosae, and Labiatae (see McNeil * Brummitt, 2003).

Even with two family names available, informal discussion benefits from shorter forms. Sometimes I’ll use the informal term Composites, or even the shortened “Comps” Similarly, I may call this the Aster family, writing that without italics. By convention, we italicize the genus, but not family name.

Adding to the possibilities for confusion, in earlier times, the genus Aster included a host of species now tucked in other genera. Many of those plants were given English common names, such as the Golden Asters that are now Chrysopsis and Heterotheca, and the very distinctive Stokesia, still called Stoke’s Aster. In recent years, taxonomists have concluded that no Composites native to the Americas should be included in genus Aster. That association lingers in common names of the blue to pink to white-flowered species. Though now relegated to the genus Symphyotrichum, we still call them all Asters, i.e. S. carolinianum the Climbing Aster and S. chapmanii the Savannah Aster.

A bit more loosely, I may at times call any or all of these plants “daisies”, which is a term so common as to become useful in reminding people that plants appearing very different may still be considered sufficiently related as to be included among the Asters. Illustrating and describing a Baccharis and calling it a “daisy” stretches the mind enough to make the point that not every plant in the family looks like a sunflower or dandelion. Asteraceous plants hold together very well and are recognized based on production of a particularly structured flowering head, a tightly-organized cluster of florets that takes on the appearance of a single flower. In street talk, a sunflower, a zinnia, a marigold, a chrysanthemum, or a dahlia will be considered a single flower. Botanically each of these “daisies” is head of small flowers – a compound inflorescence made of florets (small, modified flowers) produced on a single receptacle (the stem tip bearing one or more flowers) that is sheathed by an “involucre” into an integral structure. Each “she loves me” or “she loves me not” sacrifices a small, modified flower, not merely a petal. The hard-shelled black-striped thing folks call a sunflower seed is, sructurally, a single fruit produced by an individual floret, hundreds of which were borne on the receptacle of an impressive head of florets we call a sunflower.

“Head” is a good term. Many taxonomists will refer to this compound structure as a head of flowers, but the more technical term is “capitulum” (pl: capitula). That points to the relevance of the word Composite, which recognizes the compound floral structure of plants in this very large family.

Terminology: Some attention to descriptive terminology is useful, especially since plant treatments vary in usage. The “involucre” (the leafy envelope that encases developing florets and then surrounds the receptacle supporting the head of flowers) is made of bracts that are consistent in quantity, arrangement, and character for a species. and are reasonably similar within a genus. Keys and descriptions will describe these involucral bracts (also called phyllaries) and you’ll absolutely need to learn something about the various possibilities to identify and appreciate differences among Comps.

Inside the involucre and atop the receptacle, you’ll encounter one or both of two basic kinds of florets that form the flowering head, their differences based on the shape of the corolla (the united petals that form a short tube around anthers and style.) “Disk” florets, in which the 5 petals grow together (i.e., they are “connate”) to form a simple tube with 5 teeth or lobes are usually symmetrical and commonly fertile. Some major groups of Asters are identified by the presence of disk flowers only. The size and impact of disk florets ranges from modest (as in Baccharis and Melampodium) to showy (Cirsium and Liatris), to opulent (Stokesia).

The other kind of floret expands asymmetrically, with petals united and elongated in a lopsided way, developing the appearance of a single large petal. Think of the large yellow petals radiating from the margin of a sunflower, each of which is a floret. We describe these as “ligulate” and often call them “ligules”, or “ray flowers.” In many instances you’ll see minuscule or more evident teeth at the tip of the single petal that remind us each is made of five petal initials. Some groups (such as dandelions) are known for producing heads made of ray flowers only. Commonly, you’ll find groups of plants with both rays and disks, commonly producing ray florets around the perimeter. and disks making a textured surface in the center (hence the origin of the term).

Florets may be sterile, unisexual, or perfect. When present, the anthers of the five stamens adhere to one another. The style and bilobed stigma push out through that ring of anthers. Composites are famously self-incompatible, which means that even though pollen from the anthers of a flowering head is likely to end up all on the stigmatic surface, only pollen from another plant will successfully grow and fertilize the ovule. That reminds us that pollinating vectors, mostly insects (but in some important groups, wind, and in a few instances, birds) are necessary for reproduction. Unlike Orchids, which typically adapt to a particular pollination system, Composites tend toward very open systems in which any visitor might effectively transfer pollen.

Identifying Composites requires close observation of the fruiting body. Some florets are sterile, but seed-producing florets form a single-seeded, inferior fruit. That means this hard, dry nutlet (termed the cypsela) forms below the floret, and seats on the receptacle. Atop the nutlet (often called an achene) there’s usually some characteristic ring of scales or bristles which form at the base of the corolla, where you’d expect to find the sepals. This is the “pappus”. It is the parachute that lofts dandelion fruit and the teeth that cause Bidens fruit to cling to clothing. At it’s attachment to the receptacle, the achene (yes, these terms are interchangeable, i.e. the fruit, the nutlet, the cypsela, the achene) may be accompanied (subtended) by a basal bract, which is sometimes called a “pale”, and other times dismissed as “chaff”. (When you clean an artichoke head, the “choke” that you remove is all florets and a host of stiff, unpleasant bracts.) The shape and texture of the achene (rounded, ridged) as well as the structure of the receptacle are commonly used characters.

Identifying Composites using Keys in Floras: In most keys to Composites, the first dichotomies will challenge you to understand characteristics of flower structure mentioned above. Keys to the Tribes and Genera are available on-line in Flora of North America, through the family introduction by Theodore M. Barkley, Luc Brouillet, and John L. Strother.

Flora of Florida (Wunderlin, Hansen, and Franck, 2020, Vol VII), abbreviated as FoF, treats genera of Composites in 5 KEYS which are introduced through a separate Indexing Key. Indexing begins with “Capitula ligulate and perfect”, pointing to KEY 1. KEY 1, in turn,is a straightforward outline to the 13 genera of Florida Asters in Tribe Chicorieae Plants in this Tribe produce flowering heads with ray florets only, each floret being perfect, i.e. bearing both stamens and a pistil. Those genera are: Chicorium, Crepis, Hieracium, Hypochaeris, Krigia, Lactuca, Launaea, Lygodesmia, Pilosella, Pyrropappus, Sonchus, Taraxacum, and Youngia

The alternative entry takes you to anything that isn’t purely ligulate, leading to a couplet contrasting “Capitula radiate” versus “Capitula discoid”.

Radiate heads (those with both ray and disk flowers, including the “trimorphic” Chaptalia) points to KEY 2 (55 genera covering plants that produce yellow or orange rays) and KEY 3 (27 genera of plants that produce white pink, purple, red, or blue rays). As you might expect, this convenient but somewhat subjective color-based segregation gives rise to considerable overlap. Ten genera show up in both KEY 2 and KEY 3: Bidens, Cosmos, Echinacea, Gaillardia, Gerbera, Ratibida, Rudbeckia, Tridax, Verbesina, and Zinnia.

The alternative entry, “Discoid” (the flowering head is made of all disk florets), also indexes two KEYS, KEY 4 and KEY 5. That dichotomy requires you know the nature of the pappus, whether it’s bristly (KEY 4, which includes 39 genera) or made of scales (KEY 5, which leads to 24 genera). Centaurea is the only genus that appears in both KEY 4 and 5. But several genera cross the divide from radiate to discoid. Senecio and Solidago show up in KEYS 2 and 4; Acmella, Bidens, and Helianthus turn up in KEYS 2 and 5; and, Verbesina and Gaillardia appear in KEYS 2,3, and 5.

That means you’ll be dissecting and examining flowering heads for any new plant encountered. And in field work, with a simple hand lens, it isn’t always easy to decipher distinctions regarding the pappus, the achene, the receptacle and pales, or involucral characters. But get accustomed to using the lens and examining Composite heads, because those characters are critical to operating identification keys in Flora of Florida. In the Index to KEYS, you have to examine the pappus to determine whether the identity is hiding out in KEY 4 versus KEY 5. But the cross-representation of genera described above reminds us things are no different as we progress through key couplets. In KEY 1, you have to know this information to move past the first couplet, and in both KEY 2 and KEY 3, you’ll need to know about the pappus by the third tier of couplets.

With repeated use, I become accustomed to the basic alternatives, and skip forward in a key. For me, that is easier when headings include hints. Thus, when authors don’t include crib notes, I annotate the keys with simple reminders as to essential characteristics, lowering the inertial barrier to working through options.

In examining unknown Composites, you’ll study floral characteristics, as well as habit, persistence, stem structure, leaf characteristics, and vestiture. Even then, determination can be difficult, almost literally to the point of splitting hairs. Thankfully, for Florida the Wunderlin team has constructed a remarkable resource in the ISB website. There, you’ll find webpages for each plant reported native or escaped in Florida, along with images of herbarium specimens, photographs of living samples, and distribution maps. In working with keys and descriptions, images in ISB prove vital to determining that you are interpreting the terminology properly, while distribution maps are helpful in narrowing choices when various alternatives seem viable.

Easter Eggs: Perusing FoF keys to the Composites, you’ll discover useful shortcuts that narrow the field of options quickly. Sometimes, in constructing keys, botanists will present easy options early, so that readily distinguishable genera are quickly diagnosed. However, among the core rules for constructing keys we find a dictate against one-offs. Teasing answers out one at a time can make a key long and burdensome. It’s said to better use characters that break complex groups into equal-sized options, getting you to fewer choices sooner. However, it’s also annoying to work through a long key only to discover the plant you are studying is one of very few with some easily-noted characteristic.

There are many by-products of constructing and studying keys . Devising a key helps a taxonomist internalize and express ways to identify plants. At the user end, “working” a key is the best tool for the naturalist to get inside the thought process of the taxonomist who generated a given floristic treatment, learning which characters are most useful for identification. But examining keys also can help the student understand natural relationships within a family. Often, plants of a Subgenus or Tribe will parse out together. I’ve annotated my FoF Composite key to add that association as a learning tool, because that information is lost when the following descriptive treatments organize genera alphabetically.

Here are a few observations from FoF keys to the Composite that help me understand and identify these plants:

Dimorphic involucral bracts: At least three genera, Cosmos, Coreopsis, and Bidens can be identified readily as having two distinct kinds of bracts forming the flower head. They fall out together in KEY 2, Couplet 48. Due to flower color, the three genera surface again in KEY 3, but here the involucres isn’t mentioned. The genera are segregated as having a toothed or scaly pappus, pales on the receptacle, fertile disk and sterile ray flowers, separated by opposite leaves in Coreopsis and alternate leaves for Cosmos and Bidens.

Falsely Ligulate Disk Flowers: Examining a head of flowers of Centaurea or Stokesia, you may be deceived initially as to the nature of florets. In these plants, the disk florets can be as large and expanded as ray flowers, but they are truly tubular. The plants revery different otherwise, Centaurea having the involucre typical of other thistles in Tribe Cynareae and Stokesia. Note Couplet 2 in KEY 5 will be edited to clarify characters. Stokesia has phyllaries that are deeply pectinate or lacerate basally, while those of Centaurea are pectinate apically.

Tribal associations: Working keys are often highly artificial (implying characteristics are selected for ease of recognition, not to keep natural groups together). However, there are a few instances in which the characters are so strong as to retain natural associations. KEY 1, for example, includes Tribe Chicoriae exclusively, that group defined as having heads with all flowers being ligulate and perfect. The two genera of Inulae, Dittrichia and Pulicaria, fall out as Couplet 24 in KEY 2, herbs with a honeycombed (alveolate) receptacle that’s epaleate, alternate leaves, yellow or orange flowers, and white, simple bristly pappus. The other plant with honeycombed receptacle is Balduina, in the Heliantheae. In mentioning Tribe Heliantheae, it’s useful to note that any yellow to orange-flowered, radiate Composite with evident pales will be in this Sunflower Tribe, KEY 2, Couplet 1. Finally, all of the pink to blue flowered radiate Composites that lack pales and have a pappus of capillary bristles will be Tribe Astereae.

Sources:

Wunderlin, Richard P., Bruce F. Hansen, and Richard R. Planck, 2020. Flora of Florida, Volume VII, Dicotyledons – Orobanchaceae through Asteraceae. University of Florida Press.

Genera:

Oclemena, The Whitetop Aster

It’s a Pityopsis – the Silkgrasses

Phoebanthus – Floating Rays of Sunshine

Eurybia – Following Cassini’s Voyages

Ionactis – Rays of Blue

Emilia – A Humble Tasselflower

The Rayless Stokesia

The Northerly Chaptalia

Silphium & Friends

Flora – Main Index Page

Background – Historical Review of the Compositae

In Systematics, I base the following heavily on Bonafacino et al. Other histories are important also, and those will be introduced as encountered and assimilated. To simplify text, the names and vitals of the actors are given below in order of appearance:

Dioscorides – Pedanus Dioscorides (c40-c90 AD)
Brunfels – Otto Brunfels (1488-1534) German
Bock – Hieronymous Bock (1498-1554) German
Ruel – Jean Ruel (1474-1537)
Tournefort – Joseph Pitton de Tournefort (1656-1708) French
Vailllant – Sébastian Vaillant (1669-1722) French
Ray – John Ray (1627-1705 ) English
Michel Adanson (1727-1806) French
Paul Dietrich Giseke (1741-1796) German
Berkhey – Johannes Le Francq van Berkhey (1729-1812) Dutch
Cassini – Alexandre-Henri-Gabriel de Cassini, 1781-1832. Read more in the discussion of Eurybia
Berchtold – Friedrich von Berchtold (1781-1876)
Presl – Jan Svatopluk Presl (1791-1849) Czech
Lessing – Christian Friedrich Lessing (1809-1862), Prussian
Carl Heinrich Schultz Bipontinus (1805-1867)
George Bentham (1800-1884) English
Edward Lee Greene (1843-1915)
Karl August Hoffman (1853-1909)
Benjamin Lincoln Robinson (1864-1935), American (Illinois)
James Small (1889-1955)
Sidney Fay Blake (1892-1959)
José Cuatrecasas Arumí (1903-1996)
Ángel Lulio Cabrera (1908-1999)
Arthur Cronquist (1919-1992)
Herann Merxmüller (1920-1988)
Charles Bixler Heiser (1920-2010) American (Illinois)
Loren Rieseberg (1961- present) Canadian-American

Composites hang with their own, it’s difficult to deny their relationships, especially the radiate types (daisies, with ray and disk flowers). Herbalists, while categorizing plants based on uses for medicines, aromatics, and sustenance, still kept like things together, and daisies are like things. Dioscorides (c300 AD), for example, discussed three types of Anthemis, with yellow disks and white, yellow or purple petals, perhaps Chamomile, Marguerite, and Anthemis. Brunfels (Herbarium Vivae Eicones, 1530-1536) lists 8 different species of “Parthenium“ — Matricaria, Tanacetum, Chamaemelum (today also Matricaria), Cotula (a foetid species), Bupthalmum (he termed this the non-foetid Cotula), two that seem to be Mercurialis (Euphorbiaceae), with his eighth being Artemisia. Bock (New Kreuter Buch, 1539), also treated European daisies (Anthemis, Matricaria, Cotula, Bupthalmum, and Tanacetum) as related (though Artemesia was distinct .) Their contemporary, Jean Ruel, denoted the floral “capitulum” as a feature of the European Composite Anthemis in his 1536 De Natura Stirpium Libri Tres.

With 16th century mass printing of herbals, accounts of discovery, emergence of lavish horticultural books, growth of universities, general increase in literacy, founding of botanical gardens, and inquisitiveness of people such as Ruel, botany emerged as a natural science, dedicated to the cataloging, classification, and general study of plant life. Still, a century would pass before objective approaches surfaced and botanists began assembling groups (classes, orders) of plants that presage modern families. Seemingly in direct response to the challenge outlined in Francis Bacon’s Novum Organum, John Ray, in his Methodus Plantarum Nova (1682), described a method for organizing genera in a treatise that grouped Composites as Section IV “Herbis flore composito in genere” (pp 70-85) with 8 charts (basically keys). Nearly two decades later, French naturalist Tournefort presented Composites as a Class of three Families: 1. Fleur à fleurons (discoid); 2. Fleur à demi-fleurons (ligulate); and 3. Fleur radiée (radiate). By 1721, Sébastian Vaillant had formalized three groups similar to those of Tournefort – the Chicorieae (ligulate flowers), the Cynarocéphales (discoid thistles, Cardueae), and Corymbifères (the radiate remainder).

Linnaeus, who came to maturity in an era fresh with concepts Vaillant had promoted concerning the sexual life of plants, was wholly dedicated to using the sexual characters of flowers as a basic and profound organizing principle for species (see his Systema Naturae, 1735) defining classes and orders by numbers and disposition of stamens and pistils

Eventually recognizing 785 species of Composites (beginning with the first edition of 1753 Species Plantarum), Linnaeus grouped these plants as Class XIX -Syngenesia, with four orders (later embellished), as Bentham (1873) explains: “Polygamia aequalis, with all the flowers (or, as it is more convenient to call them, the florets) of each head hermaphrodite and fertile; Polygamia superflua, with the florets of the circumference female, those of the disk hermaphrodite, and all fertile; Polygamia frustranea, with the florets of the circumference barren, those of the disk hermaphrodite and fertile; and Polygamia necessaria, with the florets of the circumference female and fertile, those of the disk hermaphrodite but barren. To these Linnaeus added a fifth order, which, notwithstanding its analogous name Polygamia segregata, is not founded on any sexual distinction, but on inflorescence only, being characterized by the numerous uniflorous heads crowded on a common receptacle.”.

Though given credit for applying the term Compositi in his 1751 Philosophia Botanica, Linnaeus basically was following Ray’s 1682 lead. His system, fleshed out in Species Plantarum (1753) was of little lasting import, as we read in John Lindley’s 1846 The Vegetable Kingdom: “Linnaeus employed the sexes of the florets for the purpose of defining groups, but this, like all other parts of the great Swedish Naturalist’s Botanical System, is now abandoned…”

By 1760, Dutch naturalist Johannes Le Francq van Berkhey had written and published Expositio Characteristica Structurae Florum qui Dicuntur Compositi – said to be the first book dedicated solely to Composites. And by 1863, Michel Adanson managed to publish Familles des Plantes, an overwhelming and complex chart of the plant kingdom. Though Adanson formally applied the name Compositae to this family, he isn’t given credit for the family name. Because of rules setting priority for family names as beginning with de Jussieu’s 1789 Genera Plantarum, Compositae authorship is credited to P. D. Giseke in his 1792 Praelectiones in Ordines Naturalez Plantarum.

Beyond naming rights, further significant advances would await the work of Cassini. Inspired by Berkhey’s Exposito, Cassini (the fourth generation of a family famed in Astronomy) is credited as the founder of modern “synantherology” (the study of Composites). In a series of publications, beginning in 1813, he established the foundation for his Composite classification. Bonifacino, et al (2009) write: “Cassini’s work on Compositae is a masterpiece. His descriptions of organs are still valid, and for most cases, still interpreted in the same way he described and illustrated them almost 200 years ago. He is the true founder of detailed, rigorous, and systematic studies of Compositae. His modesty and respect for other botanists’ works are shown repeatedly throughout his own works, but it is also evident from the comments of scientists who knew him.” Worth including, Bonifacino et al translate Cassini’s ultimate thoughts on Composite classification:

“1. The Compositae form so tight an assemblage, that it is absolutely impossible to divide it into a small number of large natural groups, and so in order to divide it naturally it is necessary to recognize 20 small groups or tribes.

2. The characters dividing these natural tribes are those that are based on the style, plus the stigma and sweeping hairs, stamens, corolla, and the ovary; other organs can only suggest generic characters.

3. The hermaphroditic flowers possess all the diagnostic characters that define the tribe they belong to.

4. It is impossible to assign diagnostic characters to the natural tribes except for those common in the family.

5. Many Compositae offer a mix of characters that are present in several different tribes.”

Given profound familiarity with the diversity of Comps, starting with 11 sections (of the traditional tribes), within 6 years Cassini had distributed Composites among 20 tribes, a radical departure from the systems of earlier authors. With his work having appeared in many separate publications, Cassini’s immediate legacy was fragmented (though not ignored, as we learn from the work of Berchtold and Presl below.) Taxonomists are, historically, a conservative lot and it takes a few generations for fresh approaches to take hold, especially when things hit the fan in a fragmented manner. Cassini himself, sensing rejection, seemed to recognize the need for a magnum opus, instituting a compilation of previous reports as two volumes in Opuscules Phytologiques (1826) — the first book published on our topic since Berkhey’s 1870 Expositio. With Cassini’s life cut short by Cholera in April, 1832, we discover in the posthumous 3rd Volume of Opuscules (1834) that he had planned to abandon work with Composites. Quoting from Bonafacino, et. al,: “a rather somber Cassini proclaimed his definitive departure from the study of Compositae. The disputes with other botanists as well as the non-acceptance of his method by the current establishment and the indifference and dismissal of his classification by other leading synantherlogists of his time (e.g.: Kunth and Lessing) most assuredly tired this remarkable man who withdrew from studies on the family.” There was truth in his outlook; only in the past two decades have Cassini’s ideas resurfaced as prescient.

In the midst of Cassini’s work, botanists Friedrich von Berchtold (Bavarian) and Jan Svatopluk Presl (Czeck ) were busily tracking emerging literature, the impact of which they published serially as O Prirozenosti Rostlin aneb Rostlinár, an obscure and rare book, later consolidated as a 3-volume update. In their first edition, however, with a publication date of 1820, Berchtold and Presl cited Cassini, recognizing 17 plant families within Compositiflorae. One of those (which they spell Asterae) is considered the first publication of Asteraceae, now conserved as the family name.

Toward the end of Cassini’s career, his younger competitor, Christian Friedrich Lessing, working in Berlin with access to broad collections, issued a series of papers on the Berlin specimens, including keys to identification of some genera and species, the first dichotomous keys known for Composites. In 1832, Lessing published Synopsis Generum Compositarum Earumque Dispositionis Novae Tentamen Monographiis Multarum Capensium Interjectis. Describing 8 tribes, he following Cassini in emphasizing the importance of the style and stigma. His Synopsis, issued at the age of 25, held forth as the standard for Composite systematics for 6 decades. But that publication also marked the end of a promising botanical career. Traveling to Russia, Lessing was distracted by lure of gold mining, an investment of time and treasure that led him to a life of bankruptcy and obscurity in Russia. With the loss of Cassini and Lessing, the world of synantherology would await Hoffman and Bentham, decades in the future.

During the interregnum we encounter the productive, unconventional Carl Heinrich, perhaps the only specialist whose early work was conducted while serving 3 years in prison for political activity considered treasonous. Once his wealthy, well-connected family secured release, Carl Heinrich continued his work and publications on Composites as an avocation. He’s remembered for his 1866 treatment of Chicorieae, while his main contributions were taxonomic and floristic. Bonifacino et al comment “Overwhelmed by the steady flow of collections reaching him from all over the world, he often only published preliminary lists of names. Carl Heinrich’s suprageneric and infrageneric entities are a nightmare for the monographer, being often both chaotic and confused.”

Over the same period, as the world turned industrial, with trains steaming along expanding rail lines, and communication (first dots and dashes and finally signals conjuring sound) connected people in astonishing new ways, the world seemed to shrink and expand simultaneously. There was such overwhelming diversity to comprehend that grand, new, comprehensive botanical works were needed. Genera Plantarum compiled and published through the ardor and dedication of George Bentham and Joseph Dalton Hooker (supported by considerable curatorial and secretarial staff at Kew) would feature a system for organizing genera within all families of seed plants. Pages 164 through 533 of vol 2, Part 1, published in 1873 constituted Bentham’s treatment of Order 88, Compositae, treating 766 genera in 13 tribes.

We know the prodigious Bentham had a privileged childhood, with private tutors. At the age of 17, living with his family in France, his mother acquired a copy of De Candolle’s 1805 Flore Française which absorbed Bentham’s attention, as we read in his own words: “I had not the slightest idea of what was meant by any of the commonest botanical terms. All these I had to work out from the introduction, and I spent the whole morning over the Salvia…“ By 1826, the family had relocated to England, and within a few years Bentham began a long and fruitful career dedicated fully to botany, Anyone who has studied plant systematics and taxonomy will have encountered works Bentham authored, often in collaboration with other luminaries. Of course, a major achievement was Genera Plantarum, written and published with Joseph Dalton Hooker over a period of two decades, but Bentham managed to complete several family treatments for the De Candolles’ Prodromus, and the legumes for Martius’ Flora Brasiliensis being highlights.

In the introduction to his 1873 ‘Notes on the Classification, History and Geographical Distribution of Compositae’, Bentham wrote: ”The Compositae are at once the largest, the most distinct, and the most uniform, and therefore the most natural, of all orders of Pharenogamous plants … the principal changes I have proposed in the general methods of Lessing and De Candolle [on Compositae] were determined upon and worked out long before I was aware that they were in a great measure a return to that of Cassini. The confusion which his multiplication of names had produced, and the unusual terminology of his descriptions, had excited in my mind a prejudice against him, until, after completing my work of detail, I came to study his generalizations, which showed how much better his views of affinities coincided with mine than those of his successors.”

He was revered. As recently as 1977, Arthur Cronquist reflected: The single most important work on the Compositae is that of Bentham, as reflected in his treatment for the Genera Plantarum, and in his separate paper explaining and expounding that treatment. Bentham’s treatment did not, of course, spring fully formed from the brow of Zeus. It had its antecedents in the work of Cassini, DeCandolle, Lessing, and others. Bonificino et al (2009) add: “Bentham will always be remembered as one of the greatest botanists of all times, and he was responsible for bringing Cassini’s earlier works to the attention of the Compositae community.”

When the first volume of Genera Plantarum was published, Otto Hoffman was a ten-year old living in Prussia. Around the time he turned 20, studying mathematics and natural history in Berlin, Bentham’s Compositae treatment was issued. Working full-time as a high school teacher, the young Hoffman soon began consuming avocational research, studying specimens sent by collectors working mainly in Africa. With growing concentration on Composites, Hoffman assumed the task of compiling the treatment of Compositae for Engler & Prantl’s Die naturlichen Pflanzenfamilien, a 300 page work published from 1890-1894. Hoffman’s extensive (806 genera) and beautifully illustrated treatments (108 detailed drawings) for Pflanzenfamilien became the successor to Bentham’s work. The two studies of Compositae wrought influence lasting through the age of biosystematics, up to the dawning of molecular taxonomy.

History of the study of Composites (indeed, all of botany), to this moment, has been Eurocentric, driven by individuals, from strivers to luminaries, working somewhat independently. These were people of some means, often impoverished, but fortunate enough to be literate and informed, to have been educated and have taken time and resources for study and publication. It was a time of independent accomplishment, which though rightfully celebrated is never absolute; it takes a village for an individual to dedicate efforts to descriptive work. And there have always been collaborators; Bentham relied on his correspondence with American Asa Gray for help and validation in his work on Composites and other treatments.

People living and working in the New World increasingly impacted the story over the past 8 decades. An early, notoriously productive and opinionated American, E. L. Greene (see the treatment here for Oclemena) comes to mind. Excluded from the Bronsimino et al recounting, and maligned (along with Rafinesque) in other histories, Greene nonetheless contributed significantly to study of these plants, and broadly to work in several floras and other families. Kew’s POWO lists 19 Composite genera authored by Greene and accepted today, as well as another 23 in purgatory (synonymy).

Memories are kinder to the facilitators and mentors. Benjamin Lincoln Robinson, born in Illinois, just months before the end of the Civil War, bears a middle name that reflects the place and timing. Having attended Harvard, Robinson completed his PhD studies in plant antatomy at Strassburg University, returning eventually to Harvard as Asa Gray’s successor. Succeed he did, not as the grand systematist, but as pivotal in the evolving scientific community. Yes, he’s noted for work with plants related to Eupatorium, but as Curator of Harvard’s Gray Herbarium during a heyday of American collecting and taxonomy, he mentored students who built their own legacies, such as Sidney Blake, M. L. Fernald, Lyman Smith, and Julian Steyermark.

The 20th Century, with it’s devastating Depression and World Wars, realization of the genetic basis of life, rapid growth in technologies, shifting centers of population and affluence, deconstruction of historical empires, and professionalization of science would change the landscape of botanical endeavors. Collaborative work increasingly has become the hallmark of contemporary science, certainly in lab-based research, but even purely descriptive work depends increasingly on associations, administration, access, specializations, and equal recognition. Importantly, before the turn of the 19th Century, significant taxonomic and systematic work had begun natively in the US, and Canada, and in the 20th Century was beginning in other areas of the world as well. The Compositae, afterall, are cosmopolitan; each region will have plenty of challenges for local work.

It’s incredible to imagine graduate studies and systematic research continuing during WWI, but in 1917, the year before Armistice day, 11 November 1918, Sidney Blake completed his Harvard dissertation, his thesis having been taxonomic revision of Viguiera. The same year, James Small, his work and studies interrupted by service in the War was, due to injuries in 1916, returned home. By 1917, Small was married, in the midst of his graduate studies (completing his PhD in 1919), and racking up his first publication: ‘The origin and development of the Compositae’.

Two researchers born in Spain a decade before WWI, José Cuatrecasas and Angél Cabrera, would come to revitalize interest in Composites of South America. Completing his doctorate in Madrid in 1928, working initially at the University and Jardín Real in Madrid, Cuatrecasas would come to focus on Neotropical plants, spending years in Colombia, before moving to Field Museum and completing his career at Smithsonian, in DC. His emphasis would remain on South America, where he opened the minds of taxonomists about the marvelous Espeletias with their beautiful diversity in the upper altitude Paramos. His massive monograph of subtribe Espeletiinae was prepared by his survivors for publication in 2013, nearly 20 years following his death in 1996. Cuatrecasas is recognized alongside his Argentinian equal, Ángel Cabrera, also born in Madrid, but a near lifelong resident of his adopted Argentina home. Cabrera completed his doctorate in 1931, having already established a record of publications in Compositae. The thriving community of active researchers in South America have Cuatrecasas and Cabrera as models.

It’s evident that as we move closer to contemporary history, most particularly among botanists born after the WWII baby boom, we see the last of seemingly independent researchers who approach systematics as descriptive natural history – as an individual sport. With that very senior cohort, the Bonifacino et al history ends their review discussing Merxmüller and Cronquist, two researchers with very different legacies. Merxmüller, working in Munich, pursued study of Composites in the African flora, producing 11 significant studies of those plants between 1950 and 1980.

Cronquist, a somewhat larger than life figure, reigned over descriptive botany for three decades, noted for his collaboration with the amazing Armen Takhtajan. Together, Cronquist and Takhtajan would dominate discussion of flowering plant systematics at a time when the bases for opinion remained descriptive. A summary statement from Bonifacino et al speaks better than I’m able: “His research on Compositae dealt with several revisionary treatments and theoretical papers, but he was largely involved with floristic treatments in North America, an activity in which he excelled. His practical knowledge of Compositae was unparalleled, proof of which can be seen in the clarity of the keys he constructed for his floras. With regards to his ideas on the internal organization of the Compositae, and more or less in the same line of thought as Bessey and Hutchinson, Cronquist viewed Heliantheae as the ancestral group in the family and set up a series of characteristics of the primitive members of the family (Cronquist 1955). Once he made up his mind he rarely changed it, but… Carlquist was able to provide him with enough data that he decided the basal members of the family were probably woody, not herbaceous. Although many of his views on the origin and evolution of the Compositae were not corroborated by DNAs equence data, he has left a lasting legacy in his major floristic undertakings across North America, and Cronquist will always be remembered as one of the influential figures of Compositae systematics of the 20 century.”

Not included by Bonifacino et al, the history of Composites would be incomplete without mention of Charles Heiser. Have completed in doctorate at UC Berkeley in 1947, Heiser was noted during the second half of the last century as the expert on Helianthus. Work of Heiser and many others has led to massive investment in understanding crop plants.

Driven by technological advances and the possibilities of gaining more detailed insight in the basic biology of life, descriptive botany moved to the lab bench, a world one time the exclusive domain of biochemists, physiologists, and applied agricultural researchers. In that theater, the players become more numerous, their contributions more interconnected , the technology more sophisticated, the expense astronomical, and the impact less easily encapsulated.

As is evident from the work of Cassini, hindsight improves through the decades, thus legacies and advances are recast with advances in understanding. With that awareness, the story continues to the present.

But there is cause for explanation, revealing my own past and prejudices. I’m one of those boomers, a person fascinated by plants overall, a natural gardener wishing to be engaged with these green wonders, and know as much about them as possible. I envisioned a future working in a small college, teaching classes, studying and writing about the lives of plants in the field, publishing without perishing. My training supported those possibilities, beginning with descriptive, field-oriented botany at Auburn University, home of the Extension Agency, where agriculture and forestry were important. Taking any class that had a strong field component, and all the lab courses that were required, I moved to Vanderbilt for my Master’s studies. There I encountered the first of the new world, a Biology Department that had hired and semi-retired the last generation of descriptive taxonomists. I was mentored by Ben Channell and taught by Bob Kral, taxonomists who disagreed on most everything. Ben immersed students in both botanical history and the emergence of biosystematics; Bob knew as much about field study of plants in the Southeast as anyone alive. Elsie Quarterman, sat on my committee and introduced me to the worlds of Katherine Keever and E. Lucy Braun. The plant anatomist, Dean Whittier, with dry wit, was one of the greatest teachers of basic botany you’d encounter. And then there were the young turks, ecologists xxxx Eichmeyer and xxxx whose tools were experimental and mathematical, and in a congenial way, regarded my mentors as relics.

What seemed to be cutting edge information, chromosome studies, introgression and compatability, pollination ecology and population biology, speciation, island biology, even flavanoid chromatography and protein electrophoroesis would change with emergence of cladistic analysis and molecular phylogenetics. This isn’t the time to explore that topic. I mention the memories simply as introduction to the complex and rapidly-shifting contemporary era in study of Composites (and all living forms). In the following paragraphs you’ll encounter on-line presence of a web of themes and players:

Compositae Genome Project

Viewing the CGP website, that’s the Compositae Genome Project, we see the following objectives:

To develop comprehensive gene catalogs and genomic sequences for economically and taxonomically important species in the Compositae.
To develop detailed genetic maps integrating phenotypic data for agriculturally important traits with sequenced genes.
To enhance the introgression of agriculturally useful alleles from wild species.
To establish tools and resources for the Compositae that will be the basis of genomic investigations of crops and invasive species in the family

CGP projects began with geonomics of domestication traits in lettuce and sunflower,. In recent summary by principal investigator Loren Rieseberg at UBC and Indiana describes NSF grant awards of nearly $9 million. The project abstract is astonishing and informative, i.e.: “The Compositae (also known as the Asteraceae) is one of the largest, most diverse, and most economically important plant families. While lettuce, sunflower, and safflower are the three most valuable members of this family, over 40 species have been domesticated for a wide variety of uses. The Compositae also contains some of the world’s most noxious weeds, which cost the United States an estimated $35 billion annually. The primary goal of this project is to develop genomic resources for the continued study of this important plant family. This work will include: (i) sequencing the gene-rich regions of the lettuce, sunflower, and safflower genomes; (ii) generation of “gene catalogs” for 25 additional taxa, including six crops, three weeds, the wild progenitors of ten crops and weeds, representatives of five taxonomically important subfamilies within the family, and an outgroup (i.e., a close relative of the family); (iii) analyses of the prevalence of variation in gene copy number versus nucleotide variation; (iv) analyses of the effects of whole genome duplications on diversification rates within the family; (v) identification of parallel genetic changes across crop/weed lineages; (vi) construction of ultra-high density genetic maps of lettuce, sunflower, and chicory; (vii) development of permanent populations for genetic mapping in key Compositae species; and (viii) the identification and validation of candidates for genes underlying important crop- and weed-related traits. This research will result in the generation of permanent resources for the Compositae research community and will have a significant economic impact through its contributions to both crop and weed science. This project will also result in the training of students at all levels in genetics, biochemistry, physiology, comparative genomics, and bioinformatics.”

Histories are selective and subjective, melded by those who tell the stories. The story of Compositae, related here is biased toward Systematic thought, though I’ve attempted to balance the timeline with other context. Moreover, using highlights and in the treatment of genera, I tilt the lens toward work that more directly concerns botanical developments relevant to the Apalachicola Flora. Over time, I’ll continue editing this (overly detailed, I admit) story to explain how events impact understanding of the Apalachicola Flora. We’ll see how far I make it along that storyline.

Citations:

Bentham, George, 1873. Notes on the Classification, History, and Geographical Distribution of Compositae, Journal of the Linnean Society, Botany, Vol 13: 355-577

von Berchtold, Friedrich Graf and Jan Swatopluk Presl, 1820. O Prirozenosti Rostlin aneb Rostlinár (On the Nature of Plants), Prague.

Bonifacino, J. Mauricio, Harold Robinson, Vicki A. Funk, Hans Walter Lack, Gerhard Magenitz, Christian Feuillet, and D. J. Nicholas Hind, 2009. A history of Research in Compositae: early beginnings to the Reading Meeting (1975), Chapter 1, in Systematics, Evolution, and Biogeography of Compositae, eds. Vicki A. Funk, Alfonso Susanna, tod F. Stuessy, and Randall J. Bayer. Chapter Book

McNeil, Ann and R. K. Bruit, 2003. The usage of alternative names of eight flowering plant families, Taxon 52: 853-856.

Wunderlin, Richard P., Bruce F. Hansen, and Richard R. Planck, 2020. Flora of Florida, Volume VII, Dicotyledons – Orobanchaceae through Asteraceae. University of Florida Press.

Notable Historical Commentary:

John Lindley, 1846 The Vegetable Kingdom; or, The Structure, Classification, and Uses of Plants, Illustrated upon the Natural System. London

Lindley’s Title Page Quotation, taken from John Ray: “Methodum intelligo naturae convenientem quae nee alienas species conjungit, nee cognatus separat.” Raii Sylloge, praef., p. 15 Google Trans: I understand a method suitable to nature which neither joins alien species nor separates the kindred.

Pg 703 – As introduction, Lindley discusses the current (1846) status of classification of the Asteraceae:

“In proportion to its strict natural limits, depending upon the uniformity of its characters, is the difficulty of separating it into sections. Jussieu has three: Corymbiferae: the florets of which are flosculous (Lindley’s term for disk florets) in the disk, and ligulate at the circumference; Cichoraceae: the florets of which are all ligulate; and Cynarocephalae, all whose florets are flosculous; to which has since been added another division called Bilabiate. Linnaeus employed the sexes of the florets for the purpose of defining groups, but this, like all other parts of the great Swedish Naturalist’s Botanical System, is now abandoned; and yet it was not without much merit. The condition of the Order had at one time,—thanks to the neglect of Linnean Botanists and the unmethodical improvements of more careful observers, —become a chaos, the like of which had not been seen since the days of the Bauhin; but in 1830 an arrangement of much merit was proposed by the German Botanist Lessing, and at a later period De Candolle the elder applied his acute and logical mind to the elucidation of the Order. At the present day the method of the latter, essentially founded on that of Lessing, is universally followed.”

Also, pg 705 for Lindley’s summary of our understanding of the family in 1846, a time when the number of plant species thought to exist worldwide was approaching 100,000.

All parts of the world contain Composites, but in very different proportions. According to the calculations of Humboldt, they constitute 1/7 of the phaenogamous plants of France, ⅛ of Germany 1/15 of Lapland; in North America 1/6, within the tropics of America ½; upon the authority of Brown, they only form 1/16 of the Flora of the north of New Holland, and did not exceed 1/23 in the collection of plants formed by Smith upon the western coast of Africa in” Congo. (Congo, 445) In Sicily they constitute rather more than ½ (Presl.); the same proportion exists in the Balearic Islands (Cambessédes); but in Melville Island they are rather more than 1/15 (Brown), a proportion nearly the same as that of the tropical parts of New Holland. It does not, therefore, appear that Composites, as an Order, are subject to any very fixed ratio of increase or decrease corresponding with latitude. But much remains to be learned upon this subject. It is certaain that Cichoraceae are most abundant in cold regions, and Corymbiferae in hot ones; and that while in the northern parts of the world Composites are universally herbaceous plants, they become gradually frutescent, or even arborescent, as we approach the equator most of those of Chile are bushes, and the Composites of St. Helena are chiefly trees. The Bilabiate genera are almost entirely American, and from the southern provinces beyond the tropics.

De Candolle gives the following as the result of his examination of the natural habit of Composites: —Out of 8523 of which he had any knowledge 1229 were annuals, 243 biennials, 2491 perennials, 2264 under-shrubs from 1 to 3 feet high, 366 shrubs from 4 to 15 feet high, 72 small trees, 4 large trees above 25 feet high, 81 woody plants of which nothing further was known, 126 twiners or climbers, and 1201 about which nothing certain could be ascertained. These were distributed as follows : 347 in the South Sea Islands, 2224 in Africa, 1827 in Asia, 1042 in Europe, and 3590 in America; of these the Cape of Good Hope possessed 1540, Mexico 725, Brazil 722, United States and Canada 678, the Levant 610, the Continent of India 681, north and middle Europe 447, Europe at the Mediterranean 595, Australia 294.—See this author’s Collection des Memoires, No. X.

M. Lasegue estimates (Musée Delessert, 1845) the number of Composite plants at 9500, and remarks “that they have steadily continued to constitute about 1/10 of all described plants, in proportion as our knowledge of species has advanced. Thus Linnaeus had 785 Composites out of 8500 species; in 1809 the proportion was 2800 to 27,000; De Candolle described 8523 in the year 1838, which was again a tenth; and now that the estimate of species has risen to 95,000, Composite plants amount to 9500.”

Arthur Cronquist, 1977. ‘The Compositae Revisited’, Brittonia, Vol. 29, No. 2, pp. 137-153 Published by: Springer on behalf of the New York Botanical Garden Press. JSTOR Stable URL: http://www.jstor.com/stable/2805847

From page 138 of Brittonia, in 1977 Cronquist states:

“ The single most important work on the Compositae is that of Bentham, as reflected in his treatment for the Genera Plantarum (1873) and in his separate paper (1873) explaining and expounding that treatment. Bentham’s treatment did not, of course, spring fully formed from the brow of Zeus. It had its antecedents in the work of Cassini, DeCandolle, Lessing, and others.

Recently there has been a revival of interest in the work of Cassini, especially by botanists who would dissect such large genera as Eupatorium and Senecio into a horde of smaller and hopefully more natural and manageable groups. One may perhaps be pardoned for scenting a certain sense of affinity between these authors and a man (Cassini) who could propose 324 new genera of Compositae, with the subsequent comment that most of them were no more than subgenera, which he had proposed in order to attract the attention of botanists to their special distinctive features.

Many of Cassini’s papers on Compositae were published piecemeal in Cuvier’s 60- volume Dictionnaire des sciences naturelles, from 1816 to 1830. The encyclopedia is now rare, and its use even by those synantherologists who have access to it is complicated by the fact that Cassini’s placement of his general comments and synopses was determined more nearly by when he had them ready than by their logical position in the encyclopedia. Thus we may all be grateful to Robert M. King and Helen W. Dawson, who have recently (1975) extracted Cassini’s contributions to the Dictionnaire and published them as a separate 3-volume facsimile work.

In spite of Cassini’s perspicacity in recognizing relationships and detecting useful technical characters, his work was not highly influential. His idiosyncratic approach and numerous new names alienated those who might have profited from his more fundamental ideas. More than 40 years after Cassini’s death, Bentham (1873b) could write: “The principal changes I have proposed in the general methods of Lessing and DeCandolle were determined upon and worked out long before I was aware that they were in great measure a return to that of Cassini.” Tipping our cap to Cassini, we return to Bentham.

Bentham’s treatment for the Genera Plantarum was such a great improvement over what had gone before that it became a new starting point…”

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