FNA: Atriplex gardneri vs. Atriplex subg. Pterochiton

Distribution

AZ; CA; CO; ID; MT; ND; NE; NM; NV; OR; SD; UT; WA; WY; AB; MB; SK; Mexico

United States; Mexico

Discussion

Varieties 7 (7 in the flora).

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.

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

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.

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

Key

1. Fruiting bracteoles with 4 lateral wings or rows of tubercles; staminate flowers yellow or tan to brown; w Utah, e Nevada, and the w Great Plains	→ 2
1. Fruiting bracteoles lacking lateral wings, tubercles, when present, often ± aligned; staminate flowers dark brown or yellow, but if yellow; different or various distribution	→ 3
2. Staminate flowers mainly tan to brown; Great Basin	var. bonnevillensis
2. Staminate flowers mainly yellow; w Great Plains	var. aptera
3. Lower leaves opposite or subopposite; stems usually prostrate to ascending; from the Four Corners region n to Canada, and e to Manitoba, North Dakota, South Dakota, Nebraska and n Colorado	→ 4
3. Lower leaves alternate; stems often ascending to erect; various distribution	→ 5
4. Leaves mainly 1-2.5 cm wide, grayish green; bracteoles 5-9 mm wide, densely tuberculate; Uinta and Navajo basins, Utah, Colo rado, New Mexico	var. cuneata
4. Leaves mainly 0.5-1.2 cm wide, green; bracteoles 2-5 mm wide, not tuberculate or the tubercles very short; ne Utah, n to Canada and w Great Plains	var. gardneri
5. Staminate flowers mostly brown; fruiting bracteoles tapering to an acuminate apex, with apical teeth united 1/2 of length, lacking lateral teeth; Great Basin e to ne Utah, s Idaho, w Oregon, and e Washington	var. falcata
5. Staminate flowers mostly yellow; fruiting bracteoles with apex either not acuminate or truncate, the apical teeth free, subtended by lateral teeth; various distribution	→ 6
6. Leaves mainly 5-15 times longer than wide; pistillate flowers in spikes; Grand County, Utah	var. welshii
6. Leaves mainly less than 5 times longer than wide, or if longer then of different distribution; pistillate flowers in panicles; Great Basin e to Wyoming and e Utah (and nw Arizona)	var. utahensis

Source

FNA vol. 4.

Parent taxa

Chenopodiaceae > Atriplex > subg. Pterochiton

Chenopodiaceae > Atriplex

Sibling taxa

A. acanthocarpa, A. amnicola, A. argentea, A. californica, A. canescens, A. confertifolia, A. cordulata, A. coronata, A. corrugata, A. coulteri, A. covillei, A. dioica, A. elegans, A. fruticulosa, A. garrettii, A. glabriuscula, A. gmelinii, A. graciliflora, A. heterosperma, A. holocarpa, A. hortensis, A. hymenelytra, A. joaquiniana, A. klebergorum, A. laciniata, A. lentiformis, A. leucophylla, A. lindleyi, A. linearis, A. littoralis, A. matamorensis, A. mucronata, A. nudicaulis, A. nummularia, A. oblongifolia, A. obovata, A. pacifica, A. parishii, A. parryi, A. patula, A. pentandra, A. phyllostegia, A. pleiantha, A. polycarpa, A. powellii, A. prostrata, A. pusilla, A. rosea, A. saccaria, A. semibaccata, A. serenana, A. spinifera, A. suberecta, A. suckleyi, A. tatarica, A. torreyi, A. truncata, A. tularensis, A. watsonii, A. wolfii, A. wrightii

Subordinate taxa

A. gardneri var. aptera, A. gardneri var. bonnevillensis, A. gardneri var. cuneata, A. gardneri var. falcata, A. gardneri var. gardneri, A. gardneri var. utahensis, A. gardneri var. welshii

Synonyms

Obione gardneri, A. nuttallii subsp. gardneri, A. nuttallii var. gardneri

subg. Pterochiton, A. unranked Canescentes, A. unranked Confertifoliae, A. section Deserticola, A. unranked Nuttallianae, Obione section Deserticola, Obione subg. Pterochiton

Name authority

(Moquin-Tandon) D. Dietrich: Syn. Pl. 5: 537. (1852)

(Torrey & Frémont) S. L. Welsh: Rhodora 102: 426. (2001)

Web links