Tuesday, September 28, 2010

The Desmodiums

In early September, setting out into the romantic, heterogeneous matrix of diverse woodland types that make it incumbent upon me to stay in Missouri, I remained in awe of the incredible diversity of woodlands which have been managed with fire simply for their highest and best use. Compare today's woodlands in the nice, frequently burned parts of the Niangua Basin to the original survey records from the 1840s and you'll see what the General Land Office Surveyors witnessed. They soaked their trousers to the knees walking through the thick tall grasses and wildflowers in the woodlands here.

Unfortunately, the GLO survey notes don't include plant lists. If they did, they'd likely be chocked with "Desmodium sp." all over the place. Known commonly as beggar's ticks, beggar's lice, stick tights, or less commonly as tick trefoils, the Desmodiums are those darling little pink flowering legumes with the seeds that stick to your dog's ear hair, pants legs, and most especially and rigorously fleece jackets. Small curved seeds, they're covered in dense hairs that allow them to attach fervently to one's clothes. It takes a knife to scrape them off twill pants, and forget about picking them off fleece. It's a lost cause. Fresh desmodium seeds are pretty tasty--pick them off your clothes and squeeze out the ecru seed into your teeth for a nice treat. (A good way to pass time in outdoor meetings, picking seeds off your clothes and eating them.)

Missouri is home to around 20 species of Desmodiums. Many of them are loyal to managed woodlands, and are often prolific in recently burned woodlands. At the end of the burn cycle, say, around year 5, the Desmodiums taper off, waiting for a fire to trickle through the area again. High quality woodlands can harbor many species in small, localized areas, while degraded systems tend to be populated by one or two dominant species (namely D. paniculatum var. dillenii, which even grows naturally in my urban yard [though managed with fire]).

While the flowers of the Desmodiums are remarkably similar, the vegetative differences are marked and quite distinctive. When first learning Ozark woodland plants, I made horribly crude sketches (because I can't draw) of the Desmodiums with the diagnostic characteristics highly exaggerated, much like the early Etruscan art from the Naples region--the Etruscans valued hands, and hands are hard to draw, so each person was painted with five fingered paddles for hands. One Desmodium has a notably long petiole (D. marilandicum), and D. nudiflorum sends up a flowering stalk from the base. D. glutinosum is a piece of cake to identify, what with the leaves all in a whirl at the top of the stalk. While there are quite a few Desmodium species in Missouri, they're much easier to key out than the Lespedezas (je pense). Don't waste your time trying to learn the very non-illustrative common names since they really don't help much (I just learned tonight that D. rotundifolium is called dollarleaf? I'll never remember it, and I doubt kids learning botany have ever even seen the namesake silver dollar coin).

From a tiny tract of nice woodlands hemmed in by roads, some of the Desmodiums I found by stepping out of my Honda last week:

1 comment:

Anonymous said...

I've not yet tried to venture beyond "Desmodium sp." for identification. Worthy of a look.