11. Zuckia Standley, J. Wash. Acad. Sci. 5: 58. 1916.
Siltbush [for Myrtle Zuck, fl. 1897]
Stanley L. Welsh
Shrubs or subshrubs, dioecious or monoecious; herbage ± scurfy. Stems erect or ascending, branching from base, not jointed, not armed; axillary buds prominent, subglobose. Leaves alternate, subsessile or bases tapering to short petioles; blade linear or narrowly oblanceolate-spatulate to elliptic, ovate, obovate, or orbiculate, margins entire or rarely hastately lobed, apex acute or obtuse. Inflorescences commonly with some moniliform hairs; staminate flowers borne in spikes in apical axils or ± paniculate, glomerules 2-5-flowered; pistillate flowers 1-several per bract, often some vestigial. Staminate flowers not separately bracteolate, but with linear bracts subtending each spike; perianth 4(-5)-lobed; stamens 4-5. Pistillate flowers each enclosed by 2 bracteoles connate nearly to apex; perianth absent; stigmas 2. Fruiting structures: bracteoles either veinless and laterally flattened and/or 1-3-veined adaxially, or rarely unequally 3-winged, enclosed achene vertical, or bracteoles transversely flattened, oval to hexagonal and not or unequally 1-4(-5)-ridged , with 2 slightly enlarged wings, thus accommodating horizontal achene, margins not spongy-thickened; bracteoles lacking spongy cellular matrix, often subtended by single, filiform bractlet; pericarp adherent. Seeds reniform; seed coat greenish, tuberculate; embryo annular; perisperm copious . x = 9.
Species 1: w United States.
Zuckia was erected by P. C. Standley (1916) to include a solitary species, Z. arizonica, based on low, shrubby plants from saline, fine-textured substrates in northern Arizona. That taxon stood apart from Grayia brandegeei A. Gray, a species otherwise closely similar in the compression of the bracts and the horizontal position of the seeds. In the present treatment both taxa are included within an expanded Zuckia.
