Shrubs Of The Great Basin: A Natural History

Spiny Hopsage

Spiny Hopsage Grayia spinosa THE MOST FAMOUS American botanist of the nineteenth century and one of the most influential protagonists of Darwin's evolutionary theory in this country was Asa Gray. A French botanist, Christian Moquin'Tandon, de' cided to honor Gray by naming this genus ofGreat Basin shrubs after him in I894. The common name of spiny hopsage is particularly appropriate, since its fruiting structures closely' resemble those of the hops of commerce. The individual pistillate flowers, which are clustered toward the ends of the branches, are enclosed by a pair of prominent bracts almost completely united, except at the tips. These bracts may eventually get to be over a cen, timeter wide. At maturity they may be yellow, like hops, or tinged with red. Like those of the other members of the goosefoot family, the female flowers are relatively simple and lack both petals and sepals. The male flowers, which are produced in small clusters at the base of leaves or bracts, have four or five sepals surrounding an equal number of stamens. Some plants seem to produce only male or female flowers, while others produce both types. Pol, lination, as is also true of the hopsage's relatives, is by means of the wind. Although many manuals call it an evergreen, spiny hopsage, at least in the Great Basin, loses most of its leaves during the winter. Even during that season it is an easy plant to recognize, since its spine,tipped twigs are reddish and appear to have loose, whitish strings ofbark attached. None ofour other shrubs has this distinctive characteristic. Small, gray winter buds are also evident. Spiny hopsage leaves are blunt and vary somewhat in shape from narrow to relatively wide. They may be as much as 30 millimeters long under moist conditions. The whole plant is generally a meter or less in height. The range of the spiny hopsage includes not only all of the Great Basin but southern Nevada and California and eastern Washington and Wyo, 73 Spiny Hopsage SPINY HOPSAGE 75 mingo A distribution such as this indicates a high degree of plasticity in habitat requirements. Spiny hopsage is, in fact, one of the few woody shrubs which is at home in big sagebrush, shadscale, pinyon~juniper, and creosote bush communities. Its altitudinal range is comparably great, from 2,500 to 7,500 feet. Only one other species of hop~sage exists, G. brarulegei, the spineless hopsage. Its range, largely outside the Basin, extends from southern Wyoming through Colorado and Utah to Arizona. It seems to be localized primarily on clay soils. The spineless hopsage is easily recognized, as the name implies, by its lack of spines. In addition, the fruiting bracts surround~ ing the seed are notably smaller. By ranchers, the spiny hopsage is considered to be a fairly valuable browse species, so much so that a number of experiments have been conducted on seed germination and propagation by means of cuttings. The younger por~ tions are eaten, including the fruiting clusters. After the leaves and fruits have fallen during autumn and subsequently collect in depressions, they will be consumed by sheep. Arthur W. Sampson and Beryl S. Jesperson, in their comprehensive work on California range brushlands and browse plants, consider the spiny hopsage as good to fair for sheep, goats, and deer, fair to poor for cattle, and poor to useless for horses. Grayia has the ability to accumulate certain elements in its leaves, with the result that the surface soil layers under the spiny hopsage will frequently show high concentrations of potassium and magnesium. Unlike some of its relatives in the goosefoot family, it does not, however, have the ability to grow in saline soils and seems to be confined primarily to alkaline areas. It will grow in dry as well as wet sites, on mesas and flats, and on rocky talus slopes and within steep~walled canyons. An indication of its genetic vari~ ability, aside from its wide distribution, was apparent in the results of studies undertaken by M. K. Wood, R. W. Knight, and J. A. Young. They found, interestingly enough, that hopsage seed from the Mohave Desert germi~ nated at 40 degrees C. but that seed from Nevada would not. The best ger~ mination, however, occurred with an alternating temperature regime of cold and warmth, reflecting the natural cycle expected in desert climates. They also found that only a little moisture was required...