A. ACANTHOCARPA. — A OBOVATA. 321 



2. Atriplex PRiNGLEi Staridley, N. Am. Fl. 21:68, 1916. — Stems nrect to horizontally spreading from the 

 base, the whole plant only 1.5 to 3 dm. high; leaves spatulate or narrowly obovate, densely and coarsely white- 

 furfuraccous, mostly entire but a few with obscurely sinuate-dentate margins. Type, Hacienda de Angostura, 

 San Luis Potosi, Pringle 3776 (US). This was placed in the Nutlallianne by Standley, and there is no question 

 that in foliage it i.s intermediate between that group and A. ncnnlhocarpa. No leaves can be found on the type 

 specimen that are certainly dentate, but that the tendency is pre.sent is indicated by dupHcatcs of the types at 

 the University of California in which some of the leaves are plainly sinuate-dentate. The body of the fruiting 

 bracts is thicker and more spongious than in any of the forms of mdtalli, and in this respect the specimens are 

 like acanthocarpa. Possibly the habit and foliage characters may be linked with others of greater importance 

 when these littl(!-known Mexican forms are studied in the field and pringlei may then be reestablished as a 

 species or at least as a subspecies. 



3. Obione acanthocarpa Torrey, Bot. Mex. Bound. 183, 1859. — A. acanlfwcarpa. 



RELATIONSHIPS. 



Together with A. barclayana, A. obovata, and A. nultalli, this represents an early 

 Mexican stock from which many of the shrubby, dioecious Atriplexes have developed. 

 The connection with the first-mentioned of these is seen in the very much thickened 

 fruiting bracts, while in nearly all of its other features, except the dentate leaves, it is 

 more like nultalli. In the extreme form the fruiting bracts firmly unite to form a spher- 

 ical body 6 or 7 mm. in diameter, the surface of which is covered with short spinose pro- 

 cesses. In other forms the body is smaller but the processes are longer and much flat- 

 tened, resembling, except for arrangement, the wings on the bracts of A. canescens, 

 which species may have been connected with acanthocarpa at some remote period. 



ECOLOGY AND USES. 



Atriplex acanthocarpa resembles A. obovata somewhat, but is more open and branched. 

 It likewise grows in alkaline flats, but is of less importance, usually mingling with the 

 more dominant polycarpa or canescens. 



While it is doubtless grazed to a slight extent, nothing definite is known of its uses. 



37. ATIUPLEX OBOVATA Moquin, Chenop. Enum. 61, 1840. Plate 50. Broad.scale. 



Erect subshrub, woody at least at the base, 2 to 5 dm. high; branches rigidly erect from 

 a much-branched spreading base, not angled, gray-furfuraceous, the bark exfoliating 

 in strips from the old basal portions; leaves mostly alternate, the lowest opposite, short- 

 petioled, obovate or broadly elliptic, tapering to the base, very obtuse or even retuse at 

 summit, 1 to 3.5 cm. long, 0.5 to 2 cm. wide, entire or only undulate, thick, firm, nearly 

 white with a smooth, compact permanent scurf; flowers dioecious, the staminate in small 

 glomerules along the spike-like branches of oblong terminal nearly naked panicles, the 

 pistillate in small clusters in the axils of elongated terminal more leafy spikes, these some- 

 times slightly paniculate; perianth 5-cleft in the staminate flowers, wanting in the pistil- 

 late; fruiting bracts sessile or short-stalked, compressed or only slightly convex, united 

 at least to the middle, obovate or cuneate-orbicular, 4 to 5 mm. long, 5 to 7 mm. broad, 

 the summit and margins sharply toothed, the sides smooth or with a few small tubercles or 

 crests (tubercles more numerous and elongated in variety tuberata Macbride, minor 

 variation 4) ; seed 2.4 to 2.8 mm. long, light (or reddish?) brown; radicle superior. 



Northern Arizona, southern Colorado, and western Texas to Chihuahua and Zacatecas. 

 Type locality, San Luis Potosi, Mexico. The type locality was originally given as Peru, 

 but the Berlandier specimen, which is the type, came from San Luis Potosi, according to 

 Moquin (in De Candolle, Prodr. 13^:99, 1849) and according to a label with a portion of 

 the type in the Gray Herbarium, which label reads: "Hacienda del Salad, Saint Louis 

 Potosi, 1827." Collections: Arizona: Adamana, Griffiths 5121, 5125, 5126, 5128, 5129 

 (US) ; Navajo Reservation, rather common in valleys, Vorhies 27 (UC) ; Winslow, Jones 

 4109 (Herb. Jones, type of A. sabulosa Jones, minor variation 3); north end of Carrizo 

 Mountains, Standley 74? (US); Holbrook, Rusby 795 (UC); El Sauzal, September 



