Stokesia – Rayless Radiance

The Main Story

The tale of Stokesia – it’s unique qualities and identity, taxonomic history, and horticultural potential — begins with the plant and its place in the world. Here in the Apalachicola flora, in open areas, even on roadsides, we occasionally encounter a beautiful perennial composite sometimes called Stoke’s Aster.  We’ll investigate the connection between Englishman Jonathan Stokes and the namesake plant later, but this isn’t an “Aster” and isn’t from England, it’s native to the Southeast, along the Coastal Plain, from Louisiana to South Carolina. The Florida ISB Plant Atlas documents populations of Stokesia in several Gulf Coast Panhandle counties, with outliers in Flagler and Nassau Counties on the Atlantic Coast.   

Unmistakable when in flower, Stokesia lifts large shaggy heads of pale sky blue to dark lavender-blue florets (with occasional white forms) on simple stems standing 1 to nearly 3 feet tall.  But you don’t need flowers for identification.  The vegetative foliage will be easy to spot, once you have a search image for the cluster of smooth-surfaced and smooth-margined, long, oblanceolate basal leaves, each of which is characterized by a prominent cream-colored main vein.

The specific epithet laevis, in fact, tells us these leaves are hairless and toothless. 

Adaxial surface of basal leaf
Abaxial surface of basal leaf

Toothless, however, doesn’t carry beyond the basal rosette.  
Margins of leaves along flowering stems are basally toothy, nearly spinescent.  And those stems (along with some of the cauline leaves) can be plastered with soft white spreading hairs. So laevis applies to basal leaves only.

Moving apically along the stem, the leaves reduce in length, becoming bract-like and entirely dentate (this is true for Panhandle specimens, but not so for plants from further West in Mississippi and Louisiana). The stem terminates with a flowering head enveloped by multi-seriate bracts (the phyllaries) that each bear regularly-spaced, marginal spiny-teeth. Botanists use the term pectinate to suggest this comblike appearance. 

You don’t have to describe the Composite floral structure as a “flowering head”, though ‘head’ is the simple term John Strother used in his Stokesia treatment for Flora of North America. An 1857 Botanical Magazine description uses the term “capitulum” while Cassini describes the Composite inflorescence as a “calathide.” A trail of edits in a Wikipedia forum about this topic suggests the term “pseudanthium.” These varying terminologies have emerged because botanical correctness disdains using street language. A “daisy” isn’t just a flower, rather a composite structure. Many botanists smirked over Senator Everett Dirksen’s long-lived campaign to name the Marigold our National Flower (though he hedged his bets by proposing that capitulum as the “National Floral Emblem.”)

A Stokesia plant will produce multiple flowering heads. Over time, side branches develop, each terminated by a single pseudanthium, extending flowering over several weeks.  

The large and carnival-like heads sport variably-sized disk flowers masquerading as ray florets, which makes me think of Stokesia as a Disco Queen, though some botanists would use the more sedate descriptive “pseudo-radiate.”  That simply tells us the flower heads (the “capitulae” as plural) make exaggerated disk florets that look like rays.  But let’s get into it.

Examining heads closely is crucial; the first step with Composites is understanding the structure of the involucre. Is it of one set (series) of bracts, or several? Are the bracts leafy, or papery, or spiny? Are there two different kinds of bracts?

Throughout the flowering and fruiting stages, Stokesia boasts prominent and easily-recognized involucres.  There are a lot of cool, even diagnostic involucres in Aster-land, but few compete with Panhandle Stokesia for architectural detail. and duration – with their spiny, nearly “pectinate” (comb-like) margins showing for months (as is true with cauline leaves, vouchers from further West show smooth phyllary margins).

The Stokesia involucre

Botanists take great notice as to the presence or absence of chaff (bracts subtending florets), also called “pales,” on the surface of the stem forming the head – the receptacle. The Stokesia receptacle is naked, lacking pales, also termed “epaleate” – a characteristic stressed in descriptions. Rising from the receptacle, you’ll only discover that crazy assortment of disk flowers in every stage of expression, from tubular, lobed elements that are clearly standard disk florets to 1-sided, exaggerated, ray-like (ligulate) florets. This is an astonishing feature not typically explained or celebrated in written treatments. 

As a non-synantherologist, I’m pressed to imagine how close a disk flower can come to looking like a ray without being honored as such.  My only clue is that these large florets are fertile, an obligation many ray flowers avoid.  

The residual involucre cloaks maturing fruit, which are truncate achenes (cypselae) that I’m told are easy to germinate. That’s important, because Stokesia has the innate style of a garden flower. Whenever I encounter a colony, it actually seems to be something that has escaped from a garden rather than a plant yet to be cultivated and civilized.

The Back Story

An important English nurseryman, James Gordon (after whom Gordonia was named) is credited with many important early plant introductions to the Royal Gardens at Kew, when the enterprise was truly owned by the royal family.  Begun in 1759 by Augusta (mother to George III), collections grew rapidly, including plants of a blue-flowered Composite from Louisiana, said to have been provided by Gordon . The Composite would be included by the notorious John Hill in his 1768 catalog (Index Kewensis…) of the garden, listed and depicted as Carthamus laevis. A century later, Botanical Magazine (1857) reported this introduction had come to “vie in size and beauty with the celebrated Chinese Asters.  (Note that the illustration from Bot. Mag. shows more entire leaves and phyllaries than Panhandle plants, giving credence to statements that plants in England were sourced from Louisiana.)

Stokesia cyanea, Tab 4699 from Bot Mag, 3rd series, vol 13, 1857

By 1789, however, French botanist Charles Louis L’Héritier had recognized the plant as distinct from the thistles, and published the new combination Stokesia cyanea, naming the genus for Jonathan Stokes.  Curious as to how he selected Stokes for this eponym, I examined the text of L’Héritier’s book, Sertum Anglicum (which translates as an English “garland”.) 

L’Héritier gives no rationale for his selection, though there’s plenty of context, as well as intrigue.  The French botanist had, in 1786, acquired a set of herbarium specimens collected in South America by Joseph Dombey.  You’d want to read more of this history to flesh things out (check out the Wikipedia page for L’Héritier), but it seems the Spanish crown was short-changed in their agreement with Dombey, and thus made claims for the specimens in L’Héritier’s possession.  Rather than submit, the botanist took himself and his herbarium to England for 15 months to continue his studies  While there, L’Héritier encountered new plants, and I would suppose, new acquaintances.  L’Héritier clearly enjoyed his time in London. The preface to his Sertum, published on the eve of the French Revolution, quotes lines from James Thomson’s 1740 poem ‘Rule, Britannia!’

Examining other plant names published in Sertum, it seems L’Héritier had several contemporary English botanists to thank, not just Jonathan Stokes, naming the genera Witheringia for William Withering, Boltonia for James Bolton, Relhania for Richard Relhan, Lightfootia for John Lightfoot, and Dicksonia for James Dickson.  Principle among these was Withering, whose 1776 book A Botanical Arrangement of all the Vegetables naturally growing in Great Britain…., was the most current and celebrated flora available at the time L’Héritier lived in England (see the Appendix for more on Withering, as well as the amusingly complete title). Withering’s fame spread beyond England; in Europe, he was deemed “the English Linnaeus”.  This might explain the especial effort by L’Héritier to spell out his dedication to Withering, and perhaps the reason the illustration of Witheringia is the first plate in Sertum

L’Héritier’s notes on Witheringia in Sertum

Jonathan Stokes was Withering’s close associate and collaborator.  The two physicians and botanists, as well as Bolton, Lightfoot, Relhan, and Dickson were active members of London’s Linnean Society, which must have been an important source of colleagues for L’Héritier.  But the 15 months in England were just a blur in his very energetic work life. L’Héritier aggressively sought out the newest plant discoveries in both England and France.  He authored over 40 genera in Sertum and other publications, most prominently in his Stirpes Novae, a self-published series (1784 to 1791) dedicated to descriptions of new plants.  The Stirpes were issued in lavish fascicles, including a full plate illustration of each new species, most drawn by the previously little-known Pierre-Joseph Redouté.  With his numerous publications, L’Héritier is responsible for many commonly-known genera, including Agapanthus, Gloxinia, Eucalyptus, and Pelargonium. 

Born to wealth, L’Héritier’s spent his final years in penury, one of many intellectual victims of the last days of the French Revolution.  Living frugally, without livery, L’Héritier managed to keep his collections and library as well as continue his studies until he was attached and murdered  in August, 1800, returning on foot one evening from his work at the Institute.
Somewhere, in reports, minutes, and manuscripts there will be more information on the relationship that spurred L’Héritier to name a North American plant for Jonathan Stokes, but I’ve seen no evidence of direct relationship between Stokes and the plant commonly called Stokes’ Aster. That was forged by L’Héritier.

A digitized copy of the Hill illustration (1768) of the plant we call Stokesia laevis

To summarize the nomenclatural trail, we have a simple track for the single species of Stokesia.  In his 1768 list of plant collections at the Royal Gardens at Kew, John Hill published the name Carthamus laevis, along with an illustration.  In 1788, L’Héritier described the plant, which he saw at Kew, as Stokesia cyanea (knowing Hill had used a different specific epithet).  In 1816, Cassini established the genus Cartesia, and named the plant Cartesia centauroides.  Banks accepted L’Héritier’s specific epithet, keeping the plant in Carthamus, therefore publishing C. cyanea.  Finally (of course), in 1893, E. L. Greene, the man who built a massive botanical library and seems to have read and memorized every treatment he encountered, set things straight.  He accepted L’Héritier’s genus, recognizing Hill’s priority with the epithet laevis.  Thus we have the combination that has been accepted for 130 years — Stokesia laevis (Hill) Greene. 

Even today, 130 years after Greene’s publication, Florida numbers only 5 genera in the Vernonia subtribe

You may have purchased one of many cultivars sold in nurseries. Deb and I planted ‘Blue Danube’ several times in California, but the plant would not perennate for us in the dry climate. Cruising the internet, I find other cultivars, ‘Divinity’, ‘Colorwheel’, and ‘Bluestone’. There is certainly room for more selection; gardeners in the Panhandle would do well to make space in a moist sunny place for a few plants.

Set apart from others as the only species in its genus (a circumstance botanists term ‘monotypic’), Stokesia radiates its own kind of joie de vivre by establishing itself in small gardenesque installations throughout the Coastal Plain.

A flowering head that’s done with anthesis


Today, Withering is better remembered for his work with Foxglove (Digitalis). He (as well as Jonathan Stokes) conducted the earliest clinical trials regarding the efficacy of a pharmaceutical treatment for many ailments, especially for dropsy (edema). This work was published in 1785, not long before L’Héritier’s arrival in England.

In the end, Foxglove has been found effective in treating “congestive heart failure,” Stephen Edwards tells us:

The leaves today are extracted to yield digoxin, a cardiac glycoside, a complex molecule with multiple carbohydrate type rings. Digoxin appears to inhibit the Na+/K+ ATPase pump in cardiac muscle cells, leading to excess intracellular Na+, which indirectly leads to an increase in calcium ions stored in the sarcoplasmic reticulum. The increased calcium levels support a more forceful contraction of cardiac muscle, allowing the heart to work more efficiently.” (see:

Still, in the 18th century, Withering’s principle fame revolved around the Flora, the complete title being:

A Botanical Arrangement of all the Vegetables naturally growing in Great Britain with descriptions of the Genera and Species according to the System of the celebrated Linnaeus.  Being an attempt to render them familiar to those who are unacquainted with the Learned Languages.  Under each species are added, The most remarkable Varieties, the Natural Places of Growth, the Duration, the Time of Flowering, the Peculiarities of Structure, the common English Names; the Names of Gerard, Parkinson, Ray and Bauhine.  The Uses as Medicines, or as Poisons; as Food for Men, for Brutes, and for Insects.  With their appllications in Economy and in the Arts with an Easy Introduction to the Study of Botany shewing The Method of Investigating Plants, and Directions how to Dry and Preserve Specimens. The Whole Illustrated by Copperplates and a copious Glossary. 

Introducing John Hill

The “notorious” descriptor used for John Hill comes from the title of a 2018 book by George Rousseau. John Hill figures into this discussion because he included Stokesia in his 1768 catalog of living plants at Kew, in the process publishing the specific epithet laevis. But there is much to learn about this person. Apparently, despite his industry and productivity, Hill was contentious and disliked, sentiments that he seemed to cultivate. The recent book by George Rousseau seems to be a thorough treatment of this “controversial, hard-to-categorize and consequently largely forgotten figure.” (from David Allen’s review of the Rousseau book)

For a quick and easy to read summary of Hill’s contributions and controversies, check out the fact-filled 1959 article by A.D. Morris, ‘Sir” John Hill, M.A., M.D. (180601775) Apothecary, Botanist, Playwright, Actor, Novelist, Journalist’. published in Proceedings of theRoyal Society of Medicine, v. 53, and made available on the web: Here are passages from the beginning and end of the Morris article:

Morris’s introduction to John Hill
The Morris summary of Hill as a botanist

James Reveal explains the John Hill legacy in a paragraph from his 2005 ode to Michaux, ‘No Man is an Island’ (Castanea, Occ Papers 2): “As I showed in 1991, John Hill, the scourge of British botanical history—being highly critical of the Royal Society— validated many of these early generic names before Britain national hero Philip Miller did. Hill’s publications were stricken from existence by the International Code of Botanical Nomenclature in 1994 so as to protect Miller’s place in nomenclatural history.”

Many thanks to Mark Kiser and the staff of Tate’s Hell State Forest for protecting Florida’s natural resources, and for permission to study and voucher plants in Tate’s Hell, where important populations of Stokesia flourish.

Return to The Composites….

Return to Main Flora

%d bloggers like this: