Gardner’s saltbush

Obione gardneri Moquin-Tandon in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 13(2): 114. 1849; A. nuttallii S. Watson subsp. gardneri (Moquin-Tandon) H. M. Hall & Clements; A. nuttallii var. gardneri (Moquin-Tandon) R. J. Davis

Shrubs or subshrubs, dioecious or monoecious, 1-10 dm, unarmed. Stems prostrate to ascending, or less commonly erect. Leaves ± persistent, alternate or opposite to subopposite (especially proximally), sessile to petiolate; blade linear to oblanceolate, obovate, spatulate, or orbiculate, 5-55 × 2-25 mm, base cuneate, margin entire (rarely dentate), apex retuse to obtuse or rounded. Staminate flowers yellow or brown, in numerous clusters 2-4 mm wide, in spikes or panicles 2-30 cm. Pistillate flowers in spikes or panicles to 30 cm. Fruiting bracteoles 2-9 × 2-9 mm, bearing tubercles or wings or tubercles aligned in 4 rows or rarely smooth, apex toothed and usually with 2 or more lateral teeth. Seeds tan or brown, 1.5-2.5 mm wide.

Varieties 7 (7 in the flora): w North America, Mexico.

This is a widely distributed complex of intergrading genotypes of great phenotypic plasticity. The members occur commonly in fine-textured saline substrates in much of the western Great Plains and in the Intermountain Region. Diploids, triploids, tetraploids, and hexaploids (and higher polyploids, all multiples of the base number 9) are known within the complex, and hybrids are known not only between the constituents but with the other woody species which they contact, i.e., Atriplex canescens, A. confertifolia, and A. corrugata. Indeed, a case can be made for treating both A. gardneri and A. canescens within an expanded A. canescens. They are regarded here as forming two intergrading complexes, with some of the constituent varieties placed equally well within either of the species aggregations. The treatment essentially follows the alignment of taxa suggested by C. A. Hanson (1962), with the exception that they are reduced to varietal status and var. bonnevillensis and var. aptera are placed within the A. gardneri phase and not with A. canescens.