256 GENUS ATRIPLEX. 



North America it is apparently confined to the easterly part of the continent. Speci- 

 mens from the Pacific Coast referred here are now found to belong to one or another 

 of the following enumeration. 



The remaining subspecies differ from all of the preceding in their fruiting bracts, the 

 margins of which are narrower and strictly entire. (For a valuation of this feature see 

 p. 242.) They belong entirely to the Pacific Coast and the connections with Asiatic forms 

 indicate that, with the possible exception of spicata, all have reached America by way of 

 Siberia. They are most abundant along the coast of Alaska and on the adjacent islands, 

 becoming less common toward the south, none extending beyond middle California. 

 The subspecies spicata is of doubtful origin, but it seems most like hastata, except for the 

 bract differences just mentioned. Little is known of its variations or life history. The 

 numerous salient teeth of the leaves are usually distinctive, but the same type of foliage 

 is known also in subspecies hastata (for example, Newfoundland, Wagborne 49, Or). Sub- 

 species obtusa is much more widely distributed and ranges west well into Siberia, where 

 it is usually known as A. gmelini. In the United States it has been unaccountably con- 

 fused with both patula and litoraHs, but differs from both in the bracts. These are not 

 only entire, but also have a tendency toward the development of an elongated lanceolate 

 tip, so that the whole bract is considerably longer than in those forms. It has also a 

 characteristically strict or ascending habit of growth, which enables one to recognize it 

 on general appearance. Little is definitely known concerning subspecies zosteraefolius, 

 found only in a few collections made along the Straits of Juan de Fuca. Further field 

 studies msiy demonstrate the wisdom of Hooker's suggestion, namely, that it is perhaps a 

 luxuriant state of subspecies obtusa (Hooker, Fl. Bor. Am. 2:127, 1838). Fernald (Rho- 

 dora 23:264, 1921) recently has recorded A. patula bracteata Westerlund (Sveriges Atripl., 

 57, 1861) from Nova Scotia. This is much like obtusa in the foliage and bracts, but the 

 latter frequently are toothed. 



The subspecies alaskensis is so luxuriant in its foliage and the margins of the bracts are 

 so remarkably developed that it is the most outstanding of all of the forms here brought 

 under A. patula. The bracts are usually described as spongious-thickened, but the 

 thickening is perhaps no greater in proportion to the size of the body than sometimes 

 takes place in other subspecies, notably spicata. The mature bracts are so large (,6 to 

 20 mm. long) that this feature alone might seem to constitute a specific criterion, but 

 other subspecies have bracts which not infrequently reach 10 or 12 nnm. and even in 

 hastata, where these structures are usually much smaller, occasionally plants are found 

 in which they reach 12 mm. in length (minor variation 17). While this does not over- 

 throw alaskensis as a valuable taxonomic unit, it does demonstrate the inherent capacity 

 of other subspecies nearly to duplicate its most characteristic features. The radicle 

 has been described as superior, but probably it is no more so than in the other sub- 

 species. Dissections have been made of the type material, but the embryo was so 

 deformed as to render impossible a positive determination of the position. 



ECOLOGY AND USES. 



Atriplex patula is typically a halophytic annual widely distributed in salt-marshes and 

 on alkali-flats. The subspecies hastata and typica in particular often form pure consocies 

 in saline areas, though they are usually more or less mixed with other marked halo- 

 phytes. They frequently invade fallow fields, especially in the arid regions, where they 

 constitute a pioneer stage in the short subsere. The relation of hastata to the salt-content 

 of the soil has been determined by Kearney and his associates to range from 0.33 to 1.33 

 per cent in the first foot and from 0.46 to 3.3 per cent in the third foot. 



While the common forms of this species were formerly used for greens in the Old 

 World, this is rarely if ever the case in this country. Hastata and typica are grazed to 

 some extent, but are rarely abundant enough to be of much importance. 



