330 GENUS ATRIPLEX. 



39. ATRIPLEXCORRUGATA Watson, Bot.Gaz. 16:345, 1891. Plate 51. Matscale. 



Spreading subshrub, woody at the base, forming dense leafy mats, 1 to 2 dm. high; 

 branches decumbent at base but the flowering stems strictly erect, slender, not angled, 

 densely furfuraceous, the bark breaking in age into fibrous sheaths on the old parts; 

 leaves mostly opposite, the upper alternate, sessile, broadly linear or linear-spatulate, 

 narrow at base, rounded to the obtuse summit, 0.5 to 2.0 cm. long, 0.2 to 0.5 cm. wide, 

 strictly entire, densely and permanently white-furfuraceous; flowers dioecious or some- 

 times monoecious, the staminate in large glomerules along nearly naked terminal spikes, 

 the pistillate in elongated terminal spikes which far overtop the leafy stems; perianth 

 5-cleft in the staminate flowers, wanting in the pistillate; fruiting bracts sessile or sub- 

 sessile, thick, scarcely spongious, united nearly to summit, narrowly fan-shaped, the 

 terminal free portion very broad and obtuse, 4 to 6 mm. long, 3 to 4 mm. wide, the 

 sides with thick wart-like or somewhat flattened appendages; seed about 2 mm. long, 

 reddish-brown; radicle superior. 



Alkaline plains of western Colorado, southern Utah, and northern New Mexico. 

 Tjrpe locaUty, Grand Junction, Colorado. Collections: Type collection. May, 1891, 

 Eastwood (Gr, UC, US); Colorado: mesa southeast of Grand Junction, Hall 1104-9 (UC); 

 Whitewater, Hall 11050 (UC); San Juan Plains, Brandegee 1086, in part (UC); between 

 Hotchkiss and Crawford, Cowen 1118 (Gr); Mesa Grande, on the Gunnison River, 

 Purpus 334 (UC); Solitude, Utah, Coville and Kearney 2603 (US); Desert Station, 

 Utah, Rydherg and Garrett 831 4 (NY, US); Emery, Utah, Jones 5444 (NY, UC, US); 

 south of Green River, Utah, Hall 11038 (UC); mesas south of San Juan River, 5 km. 

 south of Shiprock Station, New Mexico, September 22, 1920, Hall (CI). 



SYNONYM. 



Atriplex nuttalli corrugata Nelson, in Coulter and Nelson, Man. Rocky Mt. Bot. 168, 1909. — No 

 reasons were given for this reduction to a species which differs in several fundamental features, as will be 

 indicated beyond. 



RELATIONSHIPS. 



Atriplex corrugata does not closely approach any other species in its characters. It 

 is commonly placed next to A. nuttalli in taxonomic treatments, perhaps because the 

 two are somewhat similar in superficial appearance and occupy the same habitat. 

 Where they grow together, corrugata may be recognized at a glance, for its lower, more 

 compact, and mat-like habit and the small crowded leaves give to the plant a more 

 delicate aspect. Its technical characters indicate a considerable phylogenetic divergence. 

 Especially notable are the opposite position of the leaves and the shape of the fruiting 

 bracts, which are relatively much broader above and have the free terminal portion 

 developed into a broad, smooth, essentially entire, lip-like appendage. The opposite 

 leaves suggest a possible connection with some group more primitive than the Nut- 

 tallianae, for example, the opposite-leaved A. decumbens or A. matamorensis. The 

 flowers are occasionally monoecious at the type locality. Miss Eastwood has here 

 collected specimens, some of which are purely staminate, some purely pistillate, and 

 others with several of the lower clusters in each spike pistillate, the remainder of the 

 spike staminate (Grand Junction, May, 1892, Eastwood, UC). 



ECOLOGY AND USES. 



Atriplex corrugata resembles A. nuttalli closely in its ecological behavior, evidently 

 having sprung from it as an adaptation to greater drought arising from increased salt- 

 content. They occur together throughout the range of the former, sometimes mixing 

 on apparently equal terms, but with corrugata regularly taking the more halophytic 

 depressions and ridges. It is especially typical of the most sahne bad-land ridges, 



