Photo by John Nelson Each week The Columbia Star features an explanation and picture of a mystery plant given by Dr. John Nelson, curator of the USC Herbarium. To learn more about the Herbarium, call 777-8196. Nelson’s department also offers free plant identification. www.herbarium.org

One of my undergraduate students is Carrie Hadden, pictured on the right. She has distinguished herself within our department of biological sciences by winning the “Outstanding Biology Senior” award this year.

The other day after lunch, Carrie picked up a little plant growing along the sidewalk, and began tossing it around. The plant will readily stick to your clothing and we all ended up “wearing” some.

Sweet–shrub, Carolina allspice, Calycanthus floridus Our mystery plant is common all over the US as a weed. It is a member of the botanical family “Rubiaceae”, some members of which are important economically, giving us coffee and quinine, among other things. This peculiar little herb comes up vigorously in the spring, forming bright green, tender mats of vegetation, often in disturbed places. It is blooming now in our area, and easy to find in vacant lots, roadsides, and field edges.

The flimsy stems are slender, and square in cross–section. Equipped with weak stems, the plant is unable to grow upright, so it flops around, commonly leaning and sprawling upon other vegetation. Six or eight narrow leaves cluster together up and down the stem forming whorls. The white flowers are tiny, each with four petals.

The most interesting thing about this herb is all parts of it, especially the angles of the stems, are covered with sharp, backward–pointed bristles. The tiny hooks make it very easy for the plant to snag onto passing things, cleaving readily onto fur, feathers, socks, sneakers, trousers legs, or even skin,especially hairy skin. The little barbs, present by the thousands, acting as a natural Velcro. It makes sense the plant can spread itself around by this feature. Carrie likes to call it “Velcro plant,” but it also goes by many other names. It and its near relatives have been used to stuff mattresses, and its tiny, dried fruits have been used as a coffee substitute.

Another one of the spring weeds, it makes quite a show for a few weeks, and then all the plants dry up and eventually disappear by early summer. There is plenty of time left to try the “Velcro plant” on.

Answer to last week’s mystery plant