332 GENUS ATRIPLEX. 



(UC); near Bennett Wells, Death Valley, Coville and Funston 196 (US); additional 

 localities mentioned by Merriam (N. Am. Fauna 7:325, 1893) include Lone Pine to 

 Haway Meadows in Owens Valley, California, and the following, all in Nevada: Grape- 

 vine Canon, Oasis Valley, south of Pahranagat Lake, Virgin and Lower Muddy Valleys, 

 and east of Pahrump Valley. 



MINOR VARIATIONS AND SYNONYMS. 



1. — Variation in the sculpturing and dentation of the bracts, to be expected in most species of Atriplex, is 

 here very marked. These variations often occur in varying degrees on neighboring plants. But at one locality 

 in the Tehachapi Pass, California, certain individual plants have only smooth or nearly smooth bracts; other 

 plants close by have only bracts in wliich the faces are covered with tubercles and cristate appendages; still 

 others have the two kinds of bracts in about equal proportions. This last-mentioned form appears to be a 

 hybrid between the other two, which, if this is the case, should be considered as genetic races. Samples of 

 the plants are filed at the Herbarium of the University of California (Nos. 205322, 205323, 205331, respectively). 



2. — A form with exceptionally small, ovate leaves has been collected at Maricopa, Arizona (September 3, 

 1901, Thornber, UC, Nos. 7195, 7196). In many other collections there occur similar leaves but only fascicled 

 in the axils of longer normal ones. In the Maricopa plants even a portion of the primary leaves are ovate, 

 closely sessile by a subcordate base, and only about 4 mm. long. They suggest the sagittate-sessile leaves of 

 A.julacea. (See plate 52.) 



3. Atriplex curvidens Brandegee, Proc. Calif. Acad. Sci. II, 2:201, 1889.— An extreme form as to the 

 fruiting bracts, which are broadly obovate with a cuneate base, broader than long, mostly not appendaged, 

 and with remarkably broad, thin margins which are cleft into numerous linear often curved segments. Type, 

 Comondu, Lower California, April 24, 1889, Brandegee (UC) ; known also from San Esteban Island, Gulf of 

 California, Johnston SI 93 (SF, UC). Intermediate forms in which the bracts are of the same shape and size 

 but with shorter and thicker marginal teeth have been collected near Tucson, Arizona (October 16, 1901, 

 Thornber, UC). It has been suggested by Standley (Bull. Torr. Club 44: 424, 1917) that the type sptecimen 

 may be abnormal as the result of a fungus which grew upon it. 



4. Obione polycarpa Torrey, Pacif. R. R. Rep. 4:130, 1857. — The original publication of the species, 

 although the same name appeared earlier without a description (Torrey in Emory, Notes Mil. Rec. 150, 1848). 



RELATIONSHIPS. 

 The relationships of this species are with A. julacea and A. barclayana, as has been 

 more fully indicated under the former. The fruiting bracts tend to the obovate rather 

 than to the ovate shape characteristic of julacea and the leaves are never truly sagittate- 

 clasping as in that. But on occasional plants some of the leaves are ovate-cordate and 

 closely sessile, as described under minor variation 2. Such specimens suggest a former 

 connection between the two. 



ECOLOGY. 



Atriplex polycarpa forms characteristic consocies in alkaline basins in the Southwest. 

 In the region of lentiformis it lies above the latter on better-drained soil, making the next 

 stage in the succession, the two mingling through a considerable ecotone. Beyond the 

 range of this it is the chief dominant of strongly alkaline valleys, often associated with 

 Suaeda and sometimes zoned about it. In the Santa Cruz and Gila Valleys of southern 

 Arizona it may form the center within a zone of A. canescens, or the two may mix over 

 considerable areas. It is often associated with Prosopis and Larrea, and may extend 

 up rocky slopes to mix with Parkinsonia, Fouquiera, and Cereus. In the Antelope 

 Valley of California it grows with A. confertifolia in the Larrea community. It is nearly 

 as tolerant of alkali as lentiformis, Kearney finding a salt-content of 3.12 per cent for 

 the first foot, 2.18 for the second foot, and 0.69 for the third. 



USES. 



The allscale, also called cattle spinach, probably equals A. canescens in its value as 

 a browse plant, practically always assuming a low compact form wherever cattle and 

 sheep are present. Its value is high, owing to its usual association with a number of 

 unpalatable species. In some districts, such as the westerly slopes of the San Joaquin 



