The Delta of the Rio Colorado. — 11 
individuals of a few species of plants, and these species are also 
able to maintain themselves in pure culture of some extent. An 
analysis of the vegetation of the delta confirms this view. Canes 
(Phragmites), cattails (Typha), willows (Salix), poplars (Popu- 
lus) arrow-weed (Pluchea sericea), quelite (Amaranthus Pal- 
meri), wild hemp (Sesbania), each occupy extensive areas, to the 
almost total exclusion of other seed-plants, although there are many 
places in which several of these will be found contending for the 
mastery. In all such areas of unstable equilibrium some change of the 
drainage, or of the action of the river, will be found as a disturbing 
cause. 
Nearer the Gulf are found great sloughs, in which are extensive 
fields of the “wild rice” (Uniola Palmeri), while the land subject to 
the action of the overflow of the tides supports a carpet of salt-grass 
(Distichlis) and Cressa. Throughout the entire delta the mesquite 
(Prosopis velutinea) and the screwbean (Prosopis pubescens) dot 
the landscape, and furnish examples of one of the few components of 
the vegetation, the individuals of which grow singly and apart. The 
salt bush (Atriplex) also grows singly in great globular bunches 
overtopping the head of a man, on the lower stretches of saline soil. 
In the enumeration of the following plants which have been found 
in various parts of the delta occasion is also taken to add notes as to 
known uses made of them by the Cucopa Indians: 
Achronychia Cooperi A. Gray. 
Saline soil near Volcano Lake. 
"Amaranthus Palmeri. Quelite. 
Growing in open ground flooded at highest water. The young 
plants furnish forage for grazing animals, and are also eaten by the 
Indians. The mature plant reaches a height of 10 ft., and develops a 
crop of small shiny seeds, which are collected and stored for use as 
food. 
Ammania latifolia L. 
Along the Colorado on exposed oe 
Atriplex fasciculata S. Wats. 
In saline soil near Volcano Lake. 
Cressa Truxillensis H.B. K. 
Mud-flats, forming extensive carpets with salt-grass in the south- 
ern part of the delta, in which the soil is slightly saline. 
Cucurbita palmata. 
Low ground throughout the delta. 
