29 Nov

Stillingia aquatica



A curious shrub common in local marshes is Corkwood, a confusing English name applied to more than one species. If you prefer, another “book” name is “water toothleaf,” but I’ve never actually heard anybody use that name out loud.  Oh look—it’s water toothleaf!  A stroll along any marsh boardwalk reveals the odd shrub rising stiffly above the herbaceous vegetation.  The giveaway feature is a finger-sized yellow vertical flowering spike, maybe with a dragonfly perched on it.

stillingia mid

Our Stillingia aquatica is probably the only aquatic representative of the poorly studied genus Stillingia, made up of roughly 30 species mostly in western North America to South America. Oddly, a handful of species inhabit Madagascar and Tropical Pacific Islands.   The Old World species prefer maritime habitats, hinting at arrival from the American Tropics on ocean currents?

We have two species around here, the locally common Stillingia aquatica, living up to its name in aquatic habitats, and the locally scarce Stillingia sylvatica, living up to its name preferring the sylvan glen. Some call that one Queen’s Delight. (Don’t ask.)

That vertical flower spike is a curiosity, with male (pollen-making) flowers above and female (seed- making) flowers below.  The male portion snaps off as it ages.  Any second-grader knows fowers attract pollinators with gifts of pollen and/or nectar.   The nectar generally comes from glands, nectaries, within the flower. Duh.

But nobody told Stillingia. Its nectar organs are not part of the flower, but rather enlarged stipules (basal appendages) on the small leaves associated with the flowers. Some Stillingias have similar ant-feeding (stipular?) glands on the petioles of the regular foliage leaves. These ant-food glands probably evolved into the flower-adjacent nectaries in the inflorescence.    (Stillingia sylvatica is reportedly pollinated by ants, which needs a much better look.   I’m not sold on that.)    What a weird scenario: flowers losing their real nectaries to have leaf-antfood-glands take over that function. Or so it seems.

To continue with ants, seeds on our two Stillingia species have a food packet, called a caruncle , to attract ants who disperse the seeds. Many plants attach nibbles to seeds to induce ants to drag the seeds home. The food body on the dry-habitat Stillingia sylvatica seed is large, and that in the wetland S. aquatica is small.

stillingia close

Every plant has a history of medicinal uses.   All that gets old, redundant, and unexciting when encountered species after species after species.   But few Florida plants have more prominent and controversial histories in remedies than Stillingias. Name an ailment, and Stillingias have served against it somewhere by somebody, although I’m aware of no authentic applications in modern scientific medicine. Close though!

A prominent recurrent application is against Syphilis.   What makes that more interesting is an old name for Stillingias is yaw-root.   Yaws is an ancient disease, generally not a STD, caused by a spirochaete bacterium similar to that of Syphilis.  Convergence of uses is always noteworthy.

An even-more prominent role for Stillingias turns up repeatedly with a little Google research: against cancers, and in no quiet way. It is an ingredient in the Hoxsey Herbal Therapy initiated by Harry Hoxsey in the 1920s, outlawed in the U.S. in 1960, object of much hulabaloo, and surviving defiantly today at the Hoxsey Clinic in Tijuana despite universal repudiation by modern medicine


Today’s photos are Stillingia aquatica, by John Bradford.


Posted by on November 29, 2015 in Uncategorized


6 responses to “Corkwood

  1. Steve

    November 29, 2015 at 7:04 pm

    Hey George, great article as always. Corkwood is a great looking plant, and one of those weird plants that, in my opinion, don’t quite fit into appropriate habit or form. You list is as a shrub, but it is a rather puny one, being mostly less than 1 meeter and having the characteristic of being fairly open with few leaves. But I would not categorize it as an herb, as it does have woody material, albeit soft. I have seen subshrub used sometimes. Do you have any guidance for some of these oddballs. Is there any universal standard?

  2. George Rogers

    November 29, 2015 at 7:32 pm

    Hi Steve, Just returned from your realm today…Miami. I’m afraid I don’t have any categorization other than weird. We’ll have to coin our own term.

  3. theshrubqueen

    November 30, 2015 at 1:07 pm

    Most interesting post, I have been noticing the flowers as I cruise by mushy areas. It is no wonder we have so many ants around here!

  4. George Rogers

    November 30, 2015 at 2:38 pm

    You could devote an entire career to the FL ant-plant symbioses.

  5. George Zimmerman

    November 30, 2015 at 3:25 pm

    Well though you told us not to ask I went and asked (looked up on google) why they call it Queen’s Delight. Couldn’t find anything but I did find out it was used to treat constipation!

  6. George Rogers

    December 1, 2015 at 9:28 am

    Regularity would delight the queen.


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