A. NUTTALLI. 329 



Subspecies cuneata and huxijolia are more southerly in their distribution. This, 

 together with their shorter and relatively broader leaves and bracts, the latter with 

 prominent flattened appendages, suggests a former connection with such related species 

 as obovata and acanthocarpa. The compression of the appendages occurs at times also 

 in typica and is too variable to be depended upon for purposes of identification. 



Although almost always dioecious, A. nuttalli is occasionally monoecious. For 

 example, on the plains south of Grand Junction, Colorado, where the plants are mostly 

 unisexual, a few specimens with the usual naked terminal spikes of staminate flowers 

 have also an abundance of well-formed and apparently fertile pistillate flowers in the 

 upper leaf-axils {Hall IIO48, UC). 



ECOLOGY. 



Atriplex nuttalli is the most characteristic dominant of strongly alkaline clay soils 

 throughout the larger portion of the sagebrush association of the Great Basin, and in the 

 northwestern portion of the mixed prairie. It is especially abundant in western Wyoming 

 and Colorado, Utah, and southern Idaho, where it covers thousands of square miles of 

 saline plains and bad-land slopes. Owing to the resistance it affords to wind and water 

 erosion, the plants on plains occur almost universally on low mounds 6 inches to a foot 

 high and a foot or two across, simulating dunelets. It shares this habit with its constant 

 associate in the heart of its region, namely, A. corrugata. On the strongly alkaline 

 slopes of Mancos shale and other bad-land formations, nuttalli, usually with corrugata, 

 forms the first perennial associes of the xerosere, following immediately the pioneer 

 annual communities, such as A. saccaria, A. graciliflora, and Eriogonum inflatum. On 

 the extensive plains at the base of such ranges it lies in contact with Sarcobatus and 

 Chrysothamnus nauseosus consimilis in the valleys, and A. confertifolia on less alkaline 

 slopes or on rocky ridges. The spaces between the mounds are often covered with 

 annuals, of which A. powelli, A. argentea, A. rosea, and Eriogonum inflatum are the most 

 important. The most adaptable of the subspecies appears to be falcata, which ranges 

 from saline valleys with Sarcobatus and Suaeda to uplands, where it occurs with Arte^nisia 

 tridentata and frigida. According to Kearney and his associates, the salt-content of the 

 first foot in the Sarcobatus- A triplex community of the Tooele Valley in which nuttalli 

 was found, ranges from 0.08 to 0.61 per cent, while for the fourth and fifth feet the aver- 

 ages were 1.15 and 1.58 per cent respectively. At Tucson the salt-content ran much 

 higher, as it undoubtedly does on many bad-land slopes, namely, as high as 3.5 per cent 

 in the first foot, 3.3 per cent in the second foot, and 2.5 per cent in the third. 



USES. 



This is an important browse plant in the alkaline districts where it grows. Stockmen 

 in eastern Utah report it as very good for cattle and sheep after the snow leaves in the 

 spring. In Wyoming, also, where it makes dense stands in low moist places along alkaline 

 streams, it is said to furnish large amounts of fodder relished by sheep. Like other 

 saltbushes, however, it is seldom if ever eaten by choice to the exclusion of other foods. 

 Doubtless an extensive diet of this plant alone would lead to injurious effects similar 

 to those of the related A. corrugata, which is pretty well known to be poisonous. Knight, 

 Hepner, and Nelson report on A. nuttalli as follows: 



"Thi.s is the most important of the native salt-bushes (in Wyoming) .... It is readily eaten by 

 stock and endures close grazing. Where it is cropjsed continuously, it becomes matted and sends up numerous 

 leafy shoots. It is very common in many parts of Wyoming and in the Red Desert furnishes a large part of 

 the winter forage. It readily rcseeds and maintains itself where once established. Occasionally it spreads 

 into fallow fields and here makes a thrifty growth." (Wyo. Exp. Sta. BuU. 65: 46, 1905.) 



A chemical analysis is given in connection with this report. An earlier analysis given 

 as for this plant by Forbes and Skinner (Ariz. Exp. Sta. Rep. 13:269, 1902) applies to 

 A. canescens, there having been an error in the determination of the material examined. 



