Atriplex subg. Pterochiton

Plants typically dioecious, woody, low to tall. Leaves with Kranz anatomy, usually alternate, petiolate or sessile; blade variously shaped, margin entire, hastately lobed, or variously dentate. Staminate flowers in axillary glomerules or more typically in naked terminal spikes or spicate panicles. Pistillate flowers lacking perianth. Fruiting bracteoles sessile or stipitate, united beyond middle to apex, variously shaped, winged or wingless, margin entire or toothed to lobed, faces tuberculate or lacking tubercles. Seeds erect; radicle superior or sublateral (in A. hymenelytra, A. lentiformis, and A. torreyi).

Distribution

United States, Mexico.

Discussion

Species 14 (14 in the flora).

E. Ulbrich (1934) circumscribed section Deserticola to include all of the shrubby species of Atriplex except for Atriplex canescens, which he included within Obione subgenus Pterochiton. The name Deserticola was taken by J. McNeill et al. (1983) to include not only A. canescens per se, but representatives of other groups containing woody taxa, as treated by P. C. Standley. Atriplex canescens is known to form hybrids with numerous other taxa of woody Atriplex. Thus, most of the woody species are in some large part closely allied and capable of hybridization to a greater or lesser extent. Members of the subgenus, despite their near relationships, also show affinities that lead back through time to some ancestor or ancestors common to both them and with those of subgenus Obione. They do not, however, appear to have arisen as end points of evolution from various places within that subgenus, i.e., the subgenus Pterochiton appears to be monophyletic.

Selected References

Henrickson, J. 1988. A revision of the Atriplex acanthocarpa complex (Chenopodiaceae). SouthW. Naturalist 33: 451–463.

Lower Taxa

Atriplex acanthocarpa, Atriplex canescens, Atriplex confertifolia, Atriplex corrugata, Atriplex gardneri, Atriplex garrettii, Atriplex hymenelytra, Atriplex lentiformis, Atriplex linearis, Atriplex obovata, Atriplex parryi, Atriplex polycarpa, Atriplex spinifera, Atriplex torreyi