THE AMERICAN BOTANIST 7 



flora of the desert proper, which extends for hundreds of miles 

 in every direction, then there is the hydrophytic flora about the 

 springs, seeps, and reservoirs, and hist and most interesting, 

 the flora of the cultivated lands in the oasis. The wet grounds 

 often of very limited extent, are the only places in the desert 

 that appear reasonably full of plants. Here, one might imag- 

 ine, competition of one species with another is possible ; else- 

 w^iere, the struggle is not that of plant with plant, but rather 

 that of the plant with the hard conditions of climate and soil. 

 It is well known that the water plants are very much alike the 

 world over and this region is no exception to the rule. It i.> 

 difificult to say which particular species is most abundant, but 

 the most conspicuous is most certainly the common cat-tail 

 {TypJui latifolia) which might be said to occur wherever there 

 is mrjisture. The great bullrush {Scirpus occidcntalis) is 

 nearl}- always found with the cat-tail and the two often grow 

 to a height seldom equalled elsewhere. Along the water- 

 courses, the reed-grass ( P/iragmites arundinacea) forms 

 thickets while the marshy places are well occupied by an um- 

 bellifer, Bcnila crccta, and various species of Juncus. I did 

 not see a carex of any kind in my explorations. The common 

 water-cress, however, fairly chokes up the small water-courses. 

 Neither the desert nor the wet grounds are lacking in 

 flowers, but they possess few species that can compare in con- 

 spicuousness with the globe mallows {Sphaeralcea) , the paint- 

 ed cup {CastUleja lin^ariaefolia) , desert trumpet flower {Da- 

 tura uieteloidcs), the evening primro.se {Oenothera spf), 

 crownbeard {Ximencsia encelioides), the desert thistle {Cir- 

 siitiii calcarca) and many others. Along a small irrigation 

 ditch that runs through the orchard at Tuba, I found one of 

 the show^iest of the milkweeds, Asclepias speciosa, with large 

 pink blossoms like 5-pointed stars and near by, a large yellow 

 evening primrose that mav be new to science. 



