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8-14 September 2001

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Desmodium flower

All photos & text © Hilton Pond Center

What's That Purple Flower?

If you guessed "Tick-trefoil" as a common name for the purple flower above, you'd be right. If you've never heard of "Tick-trefoil" but said it looks like some kind of wild pea, you'd still be correct. And if you're really into plants, you might have concluded confidently that it appears to be a Desmodium, a native plant of which as many as 50 species are found across North America. But many folks probably wouldn't have a clue until they looked at the fruit from this plant at Hilton Pond Center . . .

Desmodium seedpod

. . . and suddenly recognized that our little purple bloom is none other than "Beggar-Lice," a plant whose seeds are also called--as we painstakingly pluck them from our pantlegs--"those dad-blamed 'Sticktights'."

Desmodium seed hooksSticktights, indeed! Each keel- shaped seed of Tick-trefoil is covered with hundreds of tiny hooks (left) that are adapted for holding onto to animal fur but seem even more capable of grabbing our garments as we wander through meadows in late summer. It's hard to imagine how a plant can disseminate its genes with a seed that adheres so tightly to its carriers; we nearly have to use a screwdriver to pry Beggar-Lice from our socks, and heaven forbid a guy with really hairy legs should stumble into a thicket of Sticktights!

The scientific epithet Desmodium is from the Greek word for "chain," which refers to the way the plant forms its seeds end-to-end. Since Tick-trefoil is indeed a pea--it's in the Fabaceae (the Legume, or Pea, Family)--the chain is actually a pea-pod, Desmodium leafbut individual peas are separated by weak joints that easily give way on contact and allow each seed to attach to a passerby. Another clue that this plant is a pea is its clover-like three-part leaf (right), which gives rise to the name "trefoil."

In the Carolinas there are perhaps two dozen species of Desmodium, with flowers varying from white to pink to purple to blue. Most are plants that appear along fencerows or fairly early in old field succession, but a few are shade tolerant and thrive in open woods. Some Beggar-Lice plants may grow to six feet in height, but even some of the shorter species tend to tilt over almost to the ground (below left)--a mechanism that apparently improves the odds that Sticktights will come in contact with ambulating animals.

Desmodium plantNo matter what you call them-- Tick-trefoil, Desmodium, Beggar-Lice, or Sticktights--these flowers are pleasing to the eye but become a major irritation when their seeds cling so closely to our clothing. Tick-trefoils also have little apparent wildlife value. About the only animals that find them palatable are deer that occasionally browse their leaves and Bobwhite quail that eat large quantities of Sticktight seeds, and some butterflies apparently use them as host plants.

Since Beggar-Lice are legumes, the nitrogen-fixing bacteria on their roots DO enrich the soil. If for no reason other than that, we welcome Sticktights to Hilton Pond Center, in the hope they can eventually return nitrates to our nutrient-poor Piedmont red clay even as we curse them for clinging to our socks.

All photos & text © Hilton Pond Center

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Summer Tanager (second-year male)

Summer Tanager
(second-year male)
This species typically has a
much heavier bill than the
Scarlet Tanager (right)

Scarlet Tanager (juvenile female)

Scarlet Tanager
(juvenile female)
Young female Scarlet Tanagers
often look much like young female
Summer Tanagers, except for bill

 The following species were banded this week (8-14 September):

Ruby-throated Hummingbird--18
American Redstart--2
Red-eyed Vireo--1
Northern Cardinal--2
Wood Thrush--2
Carolina Wren--2
Summer Tanager--3
Eastern Bluebird--1
Scarlet Tanager--1
Swainson's Thrush--1
Eastern Towhee--1
Common Grackle--1

All photos & text © Hilton Pond Center

This Week at Hilton Pond
is part of the

(8-14 September 2001)
13 species
36 individuals

64 species
1,039 individuals

(since 28 June 1982)
122 species
39,322 individuals

Carolina Chickadee (1)

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In 2001, informative and entertaining hummingbird banding presentations were held at four Carolinas locations for more than 500 participants. For more info, and especially if your group would like to host "Hummingbird Mornings" in 2002, click on the hummingbird drawing at left.


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