Flora of North America species comparison

Varieties 5 (5 in the flora).

Herbarium materials have tended to represent a catchall for annual specimens not readily assignable to other taxa. Indeed, the distinguishing features of the Atriplex argentea complex are shared singly and often in combination with other taxa. Only by use of combinations of features can this taxon be defined. Those features, with much variation, center around the broad, typically ovate to deltoid leaf blades (often definitely 3-veined) and more-or-less compressed, sessile to subsessile (or short stipitate), fruiting bracteoles on which the marginal processes, or teeth, are mainly aligned with the plane compression, and with the faces quite smooth to variously appendaged. Still some specimens are apparently intermediate with other species, especially with the closely allied A. saccaria, with which it is at least partially sympatric.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

This species forms hybrids with Atriplex confertifolia and A. gardneri varieties (see var. bonnevillensis). Materials from the vicinity of the type locality of the species in South Dakota are low subherbaceous plants that differ from our shrubby tall material. However, the type area is presently covered with water from a dam on the Missouri River, and it is not possible to exclude the possibility of A. canescens as it has been interpreted for the past century to have existed at that site during the Lewis and Clark Expedition, if that is indeed where the lectotype was collected.

Varieties 4 (4 in the flora).

Nuttall’s new combination Atriplex canescens was based on Calligonum canescens Pursh. Watson based his new name A. nuttallii directly on A. canescens Nuttall, i.e., including the citation of Nuttall’s “Genera, 1. 197,” and on its basionym, C. canescens. The name A. nuttallii is thus a nomenclatural synonym of A. canescens and was thus illegitimate at its inception. It cannot be resurrected by even the most sophisticated arguments. A sheet of Atriplex canescens, noted as “a shrub,” taken by Nuttall on the 1810 Missouri River expedition is extant in the Lambert herbarium (PH). It bears several, obviously shrubby, staminate flowering branches, but the only pistillate branch is very immature. The name A. gardneri, also cited provisionally by Watson within the concept of A. nuttallii, clearly has priority over other names for that widely distributed species complex. Attempts at leptotypification of the name nuttallii by J. McNeill et al. (1983) and H. C. Stutz and S. C. Sanderson (1998) are both superfluous, the name being illegitimate.

C. A. Hanson (1962) noted the similarity between the occasional wingless fruiting bracteoles of Atriplex canescens and A. gardneri var. falcata. He noted further that the bracts of both species lack lateral teeth subtending the terminal ones, have terminal teeth united half their length, and have indurate bracts. Whether such similarity indicates relationship or mere coincidence is open to question. However, A. canescens is known to form hybrids with most, if not all, portions of the gardneri complex and with other woody species whose range it overlaps as well.

(Discussion copyrighted by Flora of North America; reprinted with permission.)