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Your quiz for the day: The exudation of what plant is utilized by this wide assembly of professions: violinists, bull riders, weight-lifters, baseball pitchers, flamenco dancers and gymnasts?
The common ground among these varying pursuits is the liberal use of rosin to improve performance. Perhaps you have heard the phrase “rosin up the bow,” or watched a bull rider vigorously rub a gloved hand up and down the bull rope, or watched pitchers and gymnasts casually grasp a cloth sack containing rosin to improve their grip. The purpose of these actions is to improve grip, enabled by the reaction of the rosin to skin, leather or the soles of shoes of dancers.
In Wikipedia we find: Rosin, also called colophony or Greek pitch (Pix graeca), is a solid form of resin obtained from pines and some other plants, mostly conifers, produced by heating fresh liquid resin to vaporize the volatile liquid terpene components. It is semi-transparent and varies in color from yellow to black. At room temperature, rosin is brittle, but it melts at stove-top temperatures. It chiefly consists of different resin acids, especially abietic acid. The term “colophony” comes from colophonia resina or “resin from the pine trees of Colophon,” an ancient Ionic city.
However, the drops and globules of rosin shown in the photo (Figure 1) did not come from pines, but from a forb, that of the genus Silphium, one of many forbs in the large family of Asteraceae. Rosin exudes from cuts or damaged areas of a plant. This rosin came from roughstem rosinweed, Silphium radula, which can be found over the eastern half of Texas.
Other rosin producing Silphium species in north central Texas include white rosinweed (S. albiflorum), Simpson rosinweed (S. gracile), and the rare compass plant (S. laciniatum). All of the Silphium species in Texas feature large yellow flowers with the exception of the white ray flowers of white rosinweed. The leaves of compass plant feature large leaves up to 18 inches in length, pinnately compound, and extremely rough to the touch. The leaves of compass plant are oriented north and south to capture early morning and late afternoon sunlight while remaining as small as possible during the hottest part of mid-day. The leaves of Simpson rosinweed (S. gracile) and roughstem rosinweed (S. radula) are smaller and entire, or with small teeth.
There are four species in north central Texas and about 20 species of Silphium growing across the eastern two-thirds of the United States. All species of Silphium are perennials and feature large sunflower-like flowers. These would be a welcome addition to a garden designed for pollinators. The only drawback is the scarcity of seed or potted plants to purchase.
One of the traits of the Silphium species is they are slow to grow, taking the first several years to extend the roots down ensuring that the plant can bring up moisture and nutrients. In the plant world, this trait is a good thing for survival but in our hurry-up world it means it might take two to four years to see the first flowers produced. Mature compass plant roots have been documented reaching depths of 16 feet in prairie soils. Unlike many plants in the Asteraceae family, seeds are produced only by the ray flowers of Silphium plants.
Aldo Leopold’s A Sand County Almanac tells a story on Silphium in the chapter “Prairie Birthday.”
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**ARCHIVED POST AUTHOR: rickylinex
