Shrubs Of The Great Basin: A Natural History

Rock Buckwheat

Rock Buckwheat Eriogonum sphaerocephalum As THE NAME implies, dry, rocky slopes and ridges are the habitat of the rock buckwheat. Another name for it, this one derived from the Latin spe~ cies name, is round~headed buckwheat. Rock buckwheat is a low shrub, rarely over 10 centimeters high, found abundantly in the sagebrush and pinyon~juniper communities throughout the Great Basin. The I ~to~3~centimeter, somewhat spatulate leaves tend to be whorled near the ends of the branches. Generally the leaves are densely white~ pubescent beneath, while the upper side varies from smooth to very pubes~ cent. The flowering stems, which are typically 5 to 10 centimeters long, have a whorl of leaflike bracts a little above the middle. A cluster of fused bracts with seven or eight lobes immediately supports the spherical cluster of creamy to yellow flowers, produced from May to July, depending on the ele~ vation. This cluster offused bracts, the involucre, is especially characteristic of many of the wild buckwheats. Individual flowers are composed only of sepals, as described for Kearney's buckwheat. Rock buckwheat ranges from western California, north to Washington, and east through the Nevada and Idaho portions of the Great Basin. Another very distinctive and easily recognized low, shrubby wild buck~ wheat occurs on rocky to fine gravelly slopes in the extreme western Great Basin. Wright's buckwheat, E. wrightii variety subscaposum, typically hugs the ground, forming a dense mat of short branches covered with small, elip~ tical leaves varying in length from half a centimeter to a centimeter. Some~ times older plants will form conspicuous, dense mounds up to half a meter in diameter. Wright's buckwheat, fortunately, is about the only wild buckwheat in the Basin to attract any significant commercial interest. Plants are dug up, dried, and either left in their naturally gray aspect or dyed some 100 Rock Buckwheat Wright's Buckwheat Altered Andesite Buckwheat 104 POLYGON ACEAE bizarre color and mounted in suitable containers to be sold as "Ming" trees. The woody rootstock or caudex, when exposed, frequently resembles the twisted and gnarled trunk of a very old bonsai. Although Wright's buck~ wheat is not rare or even uncommon, too much commercial interest of this sort could conceivably reduce its numbers significantly, since only wild plants and not cultivated ones appear to be used for this purpose. In the western Great Basin, Wright's buckwheat is particularly com~ mon on areas of so~called altered andesite in the Carson Range between Reno and Virginia City. These altered andesite areas have resulted from the changes produced in igneous deposits subjected to subterranean water under considerable heat and pressure. Once exposed and weathered, such rocks tend to form soils poor in nutrients and strongly acid. Altered andesite areas are easily recognized, even from a distance, since their soils favor the growth of ponderosa pine rather than the pinyon~juniper of surrounding commu~ nities. The absence of sagebrush and many other shrubs from altered an~ desite regions causes them to appear particularly barren. The several varieties of Wright's buckwheat occur in the various moun~ tain ranges throughout California; the variety subscaposum is found from 5,000 to 11,000 feet in the Sierra Nevada south to the mountains of south~ em California. Another wild buckwheat found only on these acid soils of the extreme western Great Basin is the altered andesite buckwheat, E. lobbii variety robustum. Found only in Storey and Washoe counties in western Nevada, the altered andesite buckwheat was, a few years ago, regarded as threatened. However, the consensus now is that its unique habitat does not appear to be in imminent danger from developers. This buckwheat is so distinctive that it is not easily confused with any other species in the same area. Its stout woody rootstock bears round or oval leaves with long petioles and blades between 1 and 4 centimeters long; the leaves are borne in a tuft at ground level and are very densely pubescent, appearing a light gray~green color. The leafless flower stalks bear clusters of cream~colored flowers held well above the leaves. There are many other subshrubby species ofbuckwheat to be found in the Great Basin, but to describe them all is beyond the scope of this work, and to identify them usually requires an expert on the group. ...