Plummer’s siltbush

Grayia brandegeei A. Gray var. plummeri Stutz & S. C. Sanderson, Madroño 34: 148, figs. 1c-d, 2g-l. 1987 (as brandegei)

Leaves usually 6-25 mm wide, rarely wider. Fruiting bracteoles 2(-4)-winged, samaralike; achenes vertical. 2n = 36.

Flowering summer. Fine-textured, often saline and seleniferous substrates; 1500-2300 m; Colo., N.Mex., Utah, Wyo.

Zuckia brandegeei var. plummeri occurs on the Duchesne River, Uinta, Kaiparowits, Mancos, Entrada, Summerville, and Morrison formations and other fine-textured substrates. This variety was reported by H. C. Stutz et al. (1987) from New Mexico on the basis of chromosome studies, but the herbarium specimens from San Juan County do not show the broad leaves typical of this variety. Indeed, plants assigned to this variety might not constitute a taxon in the typical sense. Rather, they seem to represent a series of highly variable, morphological segregates with the same chromosome number, having arisen independently several times from a basic brandegeei stock. The distribution is mainly at the margins of the species as a whole.