Some basic Botany, Defining and Identifying Daisies: We know Daisies, which at a glance are archetypal flowers. And Daisies are common in Florida, constituting about one out of ten plants native or naturalized here. They are, however, next gen flowers. Each “blossom” is a tight cluster of many tiny flowers, florets, grown together tightly as a head (a compact inflorescence also called a capitulum) – think Dahlia, Chrysanthemum, Dandelion, Sunflower, even Artichoke, iconic, but deceptive. Botanists call them Composites, because they make pseudanthia (false flowers) using flowers.
You don’t need much more than a single floret to determine whether or not a plant is a daisy. Tearing a Sunflower apart, you’ll find hundreds of florets of two types; each tiny flower stands out as belonging, sharing a basic structure unique to the family. At the base, you’ll find a 1-seeded, inferior (which indicates it is located below the petals) fruit, an achene, and even more technically, a cypsela. Achenes provide us popular everyday snacks, sold as Sunflower “seed” and sometimes as real seed that have been hulled. It’s market-speak. Morphologically, botanically, each black & white striped achene is a hard, dry fruit inside which a single tan seed was produced, a seed that’s free and not melded to the husk-like fruit wall. Birds at my feeder shuck the achenes, consuming the oil-rich seed inside and piling the hard fruit (pericarp) walls on the ground beneath. Woodpeckers fly off with the intact achene, which is sufficiently armored so as to endure some months stashed in a tree branch granary.
Back to observing the floret, which may require a handlens. Rising from the apex of the achene you’ll see a single tube made of five petals grown together, which in some types are symmetrical and contrite, minutely funnel-form; these are termed disk florets. Others will prove lopsided, the combined petals making a single exaggerated floral leaf called a ray, or a ligule. Florets in a flowering head might be of a single sort. Thistles, as well as Eupatorium and Liatris have simply tubular disk florets. Our native Lygodesmia, Pyrrhopappus and Lactuca make flowering heads with ray florets solely. Sunflowers produce both, except when they don’t. You’ll need to have determined the nature of florets before working through a key to Composites.
Regardless as to shape of the petals, florets variously express their sexuality. When both male and female functions are present, the floret is “perfect” and will have five anthers that adhere to each other. That peculiar nature of Composite stamens, having free filaments but surmounted by united anthers gives rise to a term some specialists use to identify themselves – they are “synantherologists,” botanists focusing on plants with conjoined anthers (syn– meaning fused, or grown together).
Pushing through the crown of anthers you’ll discover a bifid (two-lobed) stigma that can be quite showy. Each natural group of Composites often will produce florets in various predictable combinations of fertile versus sterile. Sunflowers and their near relatives produce perfect disk florets, while the petallike ray (ligulate) florets are typically sterile. The reverse is true for Silphium, heads of which bear fertile ray and sterile disk florets. Sexuality is key to identifying Composites.
You may note something was skipped; we are accustomed to complete flowers having four components, sepals, petals, stamens, and pistils. Composite florets lack normal sepals, usually bearing a pappus, a ring of bristles or scales at the apex of the achene, wrapping around the base of the tubular petals. Or a floret may have no pappus at all – a condition botanists can elect to describe as “epappate” (beginning almost any botanical noun with the letter ‘e’ means that particular structure is normally present but has been erased). Working through keys and descriptions among closely related species will often mean getting down to distinctions between seemingly minor differences in shape and texture of the pappus.
It’s not just details of the florets that prove useful in identification. The head itself holds other important features. Florets are produced at the stem tip, the receptacle. Though commonly rather flat, some kinds of Composites, notably Coneflowers, will make a mounded or protruding receptacle. Not simply the shape and size, the receptacle surface holds clues also. At the point of floret attachment there may be obvious bracts, call chaff or pales. Some plants, like Echinacea, are defined by sharply pointed projecting pales, hence the name (based on a Greek word for hedgehog or sea urchin). Others, Green Eyes (Berlandiera), produce pales that are green and leafy, making a leafy center once the corollas have been shed. Balduina is sometimes called Honeycombheads because the pales unite to make a honeycomb-like papery matrix atop the receptacle that is obvious when florets are removed. Most plants in the Aster tribe (Astereae) do not bear chaff (they are epaleate), such as Sympyotrichium, Boltonia, Erigeron, Solidago, and Baccharis; plants in the tribe (Eupatorieae) lack chaff also, i.e. Eupatorium, Liatris, etc.). The same is true for Chichorieae, examples being Pyrrhopappus and Lactuca, which are free of palea.
Finally, the head itself is enveloped by an involucre of bracts, technically phyllaries, that are characteristically distinct for many Composites. Flower heads of the related Bidens, Coreopsis, and Cosmos are readily distinguished by an inner series of cleanly wrapping, smooth bracts below which radiates a bracelet of leafy spikes. Silphium heads develop characteristic leaf phyllaries. The outer phyllaries of Stokesia are marked by finely divided, spiny lacerations described as pectinate (comb-like).
Coming full circle. take a moment and consider the family which we have termed the Compositae. With few exceptions, plant family names are based on one of the earliest groups (genera) to have been identified, which then will be given the standard ending –aceae – Liliaceae, Pinaceae, Ericaceae… Thus the common European genus Aster, the assigned base (the type) for this family yields Asteraceae. The Asters and several other large, common plant families, have proven so obviously distinct historically as to have inherited older (pre-Code) family names that refuse to go away. The Code grandfathers those names, so Compositae is condoned, as are a few others – Graminae, the alternative to Poaceae, Palmae for Arecaceae, Leguminosae for Fabaceae, Labiatae for Lamiaceae, Guttiferae for Clusiaceae, Umbelliferae for Apiaceae, and Cruciferae for Brassicaceae. Family names require no further explication. You might say “the Aster family”, or even the “Asters”, but you don’t need to say “the Asteraceae family”, which would be equivalent to saying “the Aster family family.” You may still call them Composites, i.e. Compositae, or just Comps.
Daisies in the Wild – Tales of Apalachicola Composites. Though botanically easy to define and identify, people can be excused for failing to acknowledge every Daisy because our concepts are based on the most straightforward types, the Sunflowers and Black-eyed Susans. Moreover, some plants people might believe to be Daisies aren’t. That’s not much of a problem for Floridians, in that plants most readily confused are various Southern Hemisphere Iceplants, Aizoaceae.
Composite flower heads strike botanists as stars, or symbols of the Sun, which means some genera you will encounter in the Apalachicola flora have names making that comparison – Helianthus, Helenium, Heliopsis, Phoebanthus, as well as the genus no longer applicable to North American plants, Aster. In addition to their shape, many Daisies are yellow or golden, which spawns names inspired by the golden hues of sunlight – Chrysopsis, Chrysoganum, Chrysoma, and Flaveria.
Floret characteristics inspire Composite names, predominately features of the achene. The genus Coreopsis, Florida’s state flower, has the common name Tickseed, reflected in the word ‘coreopsis’, which translates as a tick or bedbug (koris is Greek for bedbug while the suffix –opsis implies similarity in appearance). The genus Bidens suggests presence of two teeth (as in bi-dentate), so named because the fruit bears two barbs at its summit, the barbs that make Spanish Needles so wicked. In most Composites, the pappus will be a ring (or two) of bristles, more absolutely separated from the body of the achene than barbs. Haplopappus tells us the author distinguished that genus from other relatives because the achenes bear a single ring of bristles (haplo– meaning simple). The generic name Heterotheca reminds us the pappus shows two characters, achenes of disk flowers bear bristles while those of ray flowers are naked (epappate). Hymenopappus is recognized by its several transluscent scales crowning the achene. The generic name Gamochaeta, a genus of Cudweeds, indicates the pappus bristles (chaetae) are united (gamo).
Living by A Code of Nomenclature: With over sixty thousand plant genera having been described since 1753 (around fourteen thousand of which are accepted today), botanists face a real quandary in that no two genera are permitted to have the same name, and unless a name is “conserved” (which takes an act of congress), the earliest published instance is the only valid version. Stepping away from our Asteraceous theme for a moment, Torreya is the stellar example among our native plants, [PROBABLY SHOULD LOOK FOR A COMPOSITE AS THE EXAMPLE, AND MOVE THIS EXAMPLE TO THE CONIFER SECTION] in that many people wanted to commemorate the prominent New York botanist John Torrey. In 1818 Constantine Rafinesque published Torreya for a mint (today Synandra). Not satisfied with that he published a sedge named Torreya the following year. In 1821 Kurt Polycarp Joachim Sprengel described a genus of tropical mint (Clerodendron) by the name Torreya, which was not the end. In 1829 Amos Eaton honored Torrey with a shrub in the Loasaceae, today known as Mentzelia. Finally (almost), in 1838, after discussion with Torrey himself, Glasgow botanist George A. W. Arnott commemorated the great botanist by his published description of our now-famous tree that Hardy Bryan Croom had discovered several years before.
Curiously, this was not the end of homonyms. In 1843, Carl Daniel Friedrich Meissner published notes from Croom (who had perished in 1837) seemingly documenting that Croom had applied Torrey’s name to specimens of the plant Torrey and Gray had earlier described as Croomia. My simplest thought is that Meissner knew the name had no real value, rather he wanted to clean up a loose end and ensure all of Croom’s work gained credit for the thought and effort represented.
By rules established in 1905/6, this body of avid, nearly fanatical work would be quite the taxonomic muddle, totally dependent on the precise dates of publication for Rafinesque’s 1818 Torreya as compared to Nuttall’s 1818 Synandra. Given brief study, it seems the Rafinesque description was printed by April, 1818, while the date of record for Volume II of Nuttall’s Genera…., is 14 July the same year. With Code insistence on retroactivity regarding priority of publication, Rafinesque’s 1818 Torreya might be considered valid, and absolutely would have rendered all others invalid homonyms. It was absolutely clear, however, that Torrey favored (indeed, practically directed) the Abbott publication, and also true that by 1906 the tree was known far and wide as Torreya. One could also argue that Rafinesque himself invalidated his 1818 publication with the 1819 revision, but details are swept under the rug because the Code allows significant names to be conserved. The exception needed was made in the 20th Century such that Arnott’s Torreya is “conserved” for the curious relictual Gymnosperm native to ravines along the Apalachicola River. The ripples continued, perhaps because later 19th Century botanists (operating under various renegade codes) were uncertain any of the names published for the famous plant would prove viable. Querying Kew’s POWO, we learn yet more genera were proposed for Torreya: Caryotaxus in 1865, Foetataxus in 1866, Struvea in 1841, and Tumion in 1891, names there’s no time to explore.
Florida Composite Genera: Given the origins of taxonomic botany and the history of botanical Latin, the classics have been and remain fair game for generic names. Ancient figures abound. Tithonia, the genus for the Florida-adapted non-native Mexican Sunflower, attributed to René Louiche Desfontaines (1750-1833) and published in Antoine Laurent de Jussieu’s 1789 Genera Plantarum…..is based on Tithonus, consort to Eos (Aurora), the goddess of dawn who announced the daily arrival of the Sun. Desfontaines definitely knew his Greek and Roman mythology, leaving an Easter egg mystery that confounded authors of the Flora of North America.
Linnaeus and his associates, anyone fluent in Latin was steeped in the classics and well aware of Greek, Roman, and even Norse mythologies. For our flora, Linnaeus adopted Baccus (a god of wine and agriculture) to improvise the genus Baccharis for shrubby Composites common along our marshy edges. The ISB Plant Atlas maps four Baccharis species in Florida, three of which occur in the Apalachicola flora, the most common being Baccharis halimifolia, a taxon with specific epithet of somewhat arcane origin.
For this tale you need to know Linnaeus described Atriplex halimus (from halimos, Greek indicating marine, from the sea), a Saltbush native to subtropical Africa and the Mediterranean referencing its habitat in salt marshes and perhaps even the salty white texture of the leaves. Our Baccharis, with leaves similar to those of Atriplex acquired its epithet through resemblance. The common Baccharis halimifolia is present in fresh-water habitats distant from the sea, but does grow up to the marsh edge on St. George Island, where you will invariably encounter Baccharis angustifolia, described by Michaux in his 1803 Flora boreali-americana. Baccharis halimifolia actually can be a handsome plant in the landscape, with female plants (Baccharis is dioecious) quite decorative when fruiting. It’s only failure as a landscape plant is an refusal to abide domestication. Something about the growth pattern is regenerative, such that whole branches die back and new branches emerge in a natural pattern, detracting from the foliage.
With gods and saints nearly exhausted, contemporary botanists lean more heavily on the time-honored value of eponyms – names honoring people. Linnaeus coined Rudbeckia to honor the Swedish father-son duo, Olof Rudbeck the Elder, (1630 – 1702) and Olof Rudbeck the Younger (1660-1740). The Elder father, most famous for having mapped the human lymphatic system, also established the first botanical garden in Uppsala and published work on plants his son continued. Olof Rudbeck the Younger, 47 years Linnaeus’s senior, befriended the young botanist as mentor, supporter, and promoter. In his 1753 first edition of Species Plantarum, Linnaeus simultaneously commemorated Rudbeck the Elder and Rudbeck the Younger with Rudbeckia, including five species: Rudbeckia laciniata, R. triloba, R. hirta, R. purpurea (Echinacea now), and R. oppositifolia (today in Heliopsis). In his 1897 third edition, Chapman treated ten species for the Southern states. Today, POWO (Kew) documents 31 Rudbeckia, all native to North America. Of those, the ISB Atlas records ten species native to Florida.
As mentioned above, given the challenges of summonsing unique genera, contemporary botanists are forced increasingly to think outside the box when inventing a new generic name. Scattered along the Florida Gulf Coast (not reported from the Apalachicola flora) we find Rayjacksonia phyllocephala, formerly Haplopappus, but rechristened by Ron Hartman and Meredith Lane in 1996, honoring Raymond Carl Jackson. Jackson achieved note as the botanist who determined a modest herbaceous daisy of the Southwest, Xanthisma gracile (which he knew as Haplopappus), has only 2 different chromosomes (n = 2), the smallest number reported for any plant at the time (botanists have now noted several plants, both monocots and dicots, with n = 2).
What happened to Aster?: Because modern scientific naming of plants originated in Europe in the early 17th century, scholars published their most important contributions in Latin. We find the scientific names of plant families are not just Latinized, but many will be drawn from European plants, which were the earliest described botanically. Europe’s Michaelmas Daisies, associated with virtues of patience, charm, and cheerfulness, flower in late autumn, around 29 September when Christians celebrate the Feast of St. Michael the Archangel. As one of the earliest Asters to have been described, given the name Aster amellus (aster for starlike and amellus having been adopted from a flower by that name in Virgil’s Georgics.) Aster amellus became the type for genus, and Aster was designated the type for the family.
As mentioned earlier, the Asteraceae make up about 10% of Florida’s flowering plants, but none are in the genus Aster, at least not today. Indeed, the genus had long challenged American botanists specializing in Composites, one of the more outlandish of whom was Billy Turner, a researcher and professor at UT Austin. It was Billy who told a class I was with as early as 1980 that he had submitted Dysaster as a new generic name for publication, which was rejected by the editors. For me that presaged change to come, which would be substantial.
Aster had been accepted in North America since taxonomy became orderly in 1753. Chapman’s Flora as well as Small’s confidently identified Florida plants as Aster. Even as recently as 1985, Clewell’s Guide listed 26 Aster species in the Panhandle. But a decade later, taxonomists concluded the genus Aster should be limited to European plants. Most plants previously considered Aster are now classified as Symphyotrichum, while others were transferred to Eurybia, Oclemena, Ionactis and Doellingeria. What happened? How did those genera come into the picture? And what difference does it make?
Given hundreds of different kinds of aster-like plants in Europe, Asia, and North America, many more than were known in 1753 when Linnaeus established Aster, specialists utilized new analytical techniques and identified consistently distinct groupings linked to genetic markers, suggesting several different lineages, best understood as separate branches had been agglomerated over the centuries, meaning that Aster was polyphyletic (made of lineages that do not share a single ancestry within the genus.)
This reality suggested lineages that did not include the type, A. amellus, should be classified in segregate genera. Suddenly taxonomic rules kicked in and names long forgotten that might have priority required examination and possible resurrection. In plant taxonomy, there is life after death; almost any taxon ever published retains a morsel of nomenclatural life, like a Horcrux.
Forced to review the nearly overwhelming literature that has been published covering asters, Guy Nesom and his collaborators faced an enormous nomenclatural puzzle. Could they identify genera already published that would have ironclad credentials as replacements for North American plants botanists have treated as Aster for over three centuries? The answer, at least for the time being, was yes, there are valid options.
One of the most comprehensive solutions came from horticultural specimens vouchered at the botanical garden in Glasgow. In 1832, noted German botanist, Christian Gottfried Daniel Nees von Esenbeck (14 February 1776 – 16 March 1858) published a study of Asteraceae in which he described Symphyotrichum unctuosum, the decorative Glascow plant of unknown origin. Later botanists determined this new plant, which impressed Nees as different because the pappus bristles were basally united (sympysis = junction; trichos = hair), was a cultivated form of North America’s Aster novi-belgii, which Linnaeus had published in 1753. Thus, Nees’s genus and species were relegated to synonymy, botany’s taxonomic trash heap and warehouse.
But Symphyotrichum, historically “subsumed” to (“lumped into”) Linnaeus’s Aster is now liberated, reborn, such that our handsome Savannah Aster, described in 1841 as Aster chapmanii by John Torrey and Asa Gray is now classified as Symphyotrichum chapmanii, one of over 100 species in the genus. Twenty-seven species in Florida are now in the genus, including the nifty native Climbing Aster (Symphyotrichum/Ampelaster carolinianum) and the curious Scaleleaf Aster (Symphyotrichum adnatum). But not all American Asters are interpreted as Symphyotrichum; some common local plants that had been classified as Aster were judged as parts of distinct lineages.
A truly recognizable pair of plants common in our flatwoods are the Thistleleaf Aster and the nearly indistinguishable Pinewoods Aster, both now classified in Eurybia, one of nineteen genera in the Florida flora attributed to Henri Cassini. The story is related in a webpage Eurybia – Following Cassini’s Voyages, but in briefest terms Eurybia, described by Cassini in 1820, was left in obscurity by botanists who saw no good reason to dismantle the genus Aster. Here we are, two hundred years later, and contemporary scientists, using new lines of inquiry, are accepting many of Cassini’s generic concepts that were believed too radical in his lifetime.
Another botanist who scandalized some of his contemporaries was Edward Lee Greene (20 August 1843 – 10 November 1915), an astute observer with a photographic memory, an obstinate minister of unwavering opinions. It is to Greene that we owe the mysterious genus Oclemena, which he established in 1903 for O. acuminata, a combination ignored by many botanists and floras until 1995 when Guy Nesom resurrected the genus, expanding the concept to include our Whitetop Aster, Oclemena reticuata. More information on this plant is available at Unsinking Oclemena.
You perhaps thought we were done with Christian Gottfried Daniel Nees and his 1832 publication. But Honoring Ignaz Döllinger, a brilliant contemporary embryologist and accomplished microscopist, someone he knew through the Leopoldina Academy (Nationale Akademie der Wissenschaften Leopoldina), Nees described Doellingeria, a modest genus of two species. Nees notes (using Google Translate for the Latin): “Doellinger, a courtier to the king of Bavaria, professor of anatomy and physiology at the University of Munich, a botanist and scholar, when I had turned my attention to the study and cultivation of Asters, helped my studies and was the author and advocate of the development of a monograph.”
The type, Doellingeria umbellulata, native to most of Eastern North America (Alabama and Georgia northward) isn’t recorded for Florida. But Cornel-leaf Whitetop, Doellingeria infirma has been recorded from Gadsden County, and Southern Whitetop, D. sericocarpoides is noted from Washington and Walton counties westward.
Until recently, the remaining fallout of our Aster breakup would be the orphaned and charming Ionactis lineariifolia, a plant of concerning identity. another legacy of the indomitable Edward Lee Greene, who admitted three species to his newly crafted genus. You can explore more about Ionactis and Greene in the webpage titled Ionactis – an early blue-ray-disc, Our Florida plant perplexes me because in mid-summer, 2026, I encountered a flowering specimen that (from every perspective) must be our Ionactis, though different both in flowering out of season and sporting a significantly broader flowering head. Thus it has been intriguing to learn that as early as 1992, Nesom and others began reimagining how this genus should be circumscribed. Even more recently, in 2020 Nesom published the new species Ionactis repens, based on type material collected in Alabama, distinguished from I. lineariifolia principally by its colonial habit. You’ll discover in the ISB Atlas the determination has been made that plants in our area should now be regarded as Ionactis repens.
Through The Rabbit-Hole: If we allow ourselves, for a few potentially bewildering moments, to examine a list of Florida Composites organized (classified) based on how specialists see them today, we earn the privilege of making associations that could help both in identification as well as understanding. We pass, however, through a short stretch of turbulent waters as we attempt to get our thoughts around the largest family of flowering plants and one the largest groups in our flora. The Asteraceae is also an area of active research, with basic understanding shifting regularly. One major study discusses two SubFamilies, while another recognizes twelve or more. The comforting reality is that practically all species known are covered by four of the several SubFamilies, the remaining few hundred being such outliers as to be distributed among the others.
Even then, the Subfamily that includes Asters, Daisies, and Sunflowers includes around 70% of known species worldwide, those then classified into about twenty groups called Tribes. The great majority of our native Composites are in three tribes of this Subfamily.
The Chicory subfamily, with Dandelions and Lettuces, is easily identified. In almost any key to the family, plants in this group fall out quickly as producing heads composed of all ligulate (ray) florets and typically producing milky sap. Quite significant for our flora is the Vernonia Subfamily, which groups Vernonia, Elephantopus, and Stokesia. Cirsium species are our only native Thistles, and we have a single one native plant that represents the tropical Mutisia subfamily, Chaptalia. are
Yes, it is a bit much, but examining the current understanding of which genera are believed most closely related (thus in the same Tribe), and which tribes are thought most related (thus in the same Subfamily) may help in constructing a framework for understanding this important family.
Examining the state flora, this is how things shake out at the moment. There are some real surprises, which will be covered below. The lists below outline Florida plants by Subfamily, Tribe, and Genus.
Subfamily Asterioideae:
- Anthemideae: Achillea, Anthemis, Artemisa, Cladanthus, Glebionis, Leucanthemum, and Solvia
- Astereae: Aphanostephus, Baccharis, Bigelowia, Boltonia, Bradburia, Brintonia, Chrysoma, Chrysopsis, Conyza, Croptilon, Doellingeria, Erigeron, Eurybia Euthamia, Gerbera, Heterotheca, Ionactis, Oclemena, Pityopsis, Rayjacksonia, Seriocarpus, Solidago, Symphyotrichum (Ampelaster)
- Eupatorieae: Ageratina, Ageratum, Brickellia, Carphephorus, Chromolaena, Conoclinium, Eupatorium, Eutrochium, Fleishmannia, Garberia, Hartwrightia, Koanophyllon, Liatris, Mikania, Praxelis, Sclerolepis
- Gnaphalieae: Antennaria, Facelis, Filago, Gamochaeta, Pseudognaphalium
- Heliantheae: Acanthospermum, Acmella, Ambrosia, Arnica, Balduina, Berlandiera, Bidens, Borrichia, Calyptocarpus, Chrysogonum, Coreopsis, Cosmos, Dracopsis, Echinacea, Eclipta, Enydra, Flaveria, Gaillardia, Gallinsoga, Helenium, Helianthus, Heliopsis, Hymenopappus, Iva, Lagascea, Marshallia, Melampodium, Melanthera, Palafoxia, Parthenium, Pascalia, Pectis, Phoebanthus, Polymnia, Ratibida, Rudbeckia, Silphium, Smallanthus, Sphagneticola, Synedrella, Tagetes, Tetragonothecda, Thymophylla, Tridax, Verbesina, Xanthium, Zinnia
- Inuleae: Dittrichia, Pulicaria
- Plucheeae: Pluchea, Pterocaulon, Sachsia
- Senecioneae: Arnoglossum, Crassocephalum, Emilia, Erechtites, Euryops, Gynura, Hasteola, Packera, Pseudogynoxys, Senecio.
Plants in Subfamily Asterioideae are not so straightforward. If you encounter a Composite with both ray and disk flowers in the head, that is a solid indicator you could be examining a plant in this group, but far from absolute. The Eupatorieae, including Eupatorium, Carphephorus, and Liatris make heads typically discoid heads, as does Pluchea and Baccharis. Certainly understanding and treatment of Aster and allied plants (Tribe Astereae) has shifted with greater documentation and study. With over 3,000 species, Tribe Astereae, which includes obvious Daisies (Asters, Goldenasters, Goldenrods, Fleabanes (Erigeron) and Doll’s Daisy (Boltonia), as well as the shrubby and very distinct Baccharis, is somewhat easier to circumscribe. Vegetatively, these plants bear simple leaves (rarely deeply divided) that alternate along stems; they do not produce milky sap. The flowering heads are described generally as “heterogamous radiate”, which tells us they are “daisy-like”, with an outer ring of female ray florets and a central “eye” of perfect disc florets (the great exception being Baccharis, which lacks ray florets and is dioecious). Most genera lack palea on the receptacle.
The Heliantheae includes many plants with radiate flowers (daisy-like with both disk and ray florets), so distinguishing these plants from those in the Astereae can be useful. Vegetatively, the Heliantheae commonly bear opposite leaves which are frequently 3-veined basally and often coarse or scabrous in texture. The flowering heads are typically paleate (with chaff). The anthers are often darkened as are the hard-walled achenes. If a pappus is present, it will more likely be erose, or made of scales or awns rather than bristles. True to the name, yellow- to orange-colored petals mark the group.
Eupatoreae produce flowering heads composed purely of disk flowers, all of which are perfect and fertile. In contrast to the Heliantheae, there is a distinct absence of yellow floral pigments, flower colors ranging from whites to pinks and blues. The stylar lobes can be conspicuous, will be blunt, sometimes swollen and papillate, but not invested with trichomes.
Subfamily Carduoideae:
- Cynareae: Centaurea, Cirsium
Subfamily Cichorioideae:
- Cichorieae: Cichorium, Crepis, Hieracium, Hypochaeris, Krigia, Lactuca, Launaea, Lygodesmia, Nabulus, Onopordum, Pilosella, Pyrrhopappus, Sonchus, Taraxacum, Youngia
Subfamily Vernonioideae:
- Arctotideae: Haplocarpha
- Vernonieae: Centrantherum, Cypanthillium, Elephatopus, Pseudoelephantopus, Stokesia, Vernonia
Finally, in Subfamily Mutisioideae:
- Mutiseae: Chaptalia
de Jussieu, Antoine Laurent, 1789. Genera plantarum secundum ordines naturales disposita.
Nees von Esenbeck, Christian Gottfried Daniel, 1832. Genera et species Asterearum. Nuremberg. BHL https://doi.org/10.5962/bhl.title.46989
Link to this Page: https://botanyincontext.com/daisies-composing-flowers/
A resource worth exploring is the Astereae Lab website John Semple and his associates have maintained regarding Asters, Goldenasters, and Goldenrods.