7O BOTANICAL FEATURES OF NORTH AMERICAN DESERTS. 
Streptanthus, one of the mustard family, soon reaches the adult stage, with 
its deep greenish stems and rather lush leaves, which show but little 
indication of belonging to the desert. Two of the borages, Harpagonella 
and Pectocarya, occupy the most prominent place in this group of plants, 
the soil being generally so thickly sown with their seeds that the rains bring 
up a dense carpet of these plants; every square inch of available space on 
Tumamoc Hill is occupied with their short hairy stems, the burs being 
quickly matured, and in the dry weeks of April forming an unpleasant 
feature of a walk off the trail. Two plantains abound: Plantago artstata 
stays on the slopes, while P. 7gnota is abundant over vast areas of gravelly 
or sandy mesa, the silvery hairy and grayish appearance of the leaves 
being such that it is difficult to determine at a glance whether the plants 
are alive or dead. Of the annuals these two are furnished with the struc- 
tures most generally characteristic of forms that live in dry places. Pha- 
celia tanacetifolia, with its scorpioid inflorescence, is scattered among the 
rocks and on the slopes over a wide range, and as it does not come into 
bloom until well on with the coming of dry weather, it and its neighbor, 
Amsinckia, with yellow flowers, have some of the features of desert 
plants. Early in April, shining silvery balls of fruit, reminiscent of the 
dandelion, are met frequently, and these prove to be relatives of that 
weed, being Mzicroseris linearts, with erect linear leaves around the scape 
which bears the fruit, and Rafineskza, with shorter laciniate leaves on its 
thicker stems. The wild carrot, Daucus pusillus, holds its umbels of 
inconspicuous flowers but a few inches above the ground, and these ripen 
seeds in April, when the entire plant quickly dries up. Bowlesza lobata is 
abundant in certain localities, while two gilias, relatives of the phlox of 
the gardens, are abundant. Gzlza floccosa displays its small star-shaped 
flowers everywhere on short simple or branched stems, which, with a 
supply of water, take on some stature and throw out laterals, but which 
usually send up a single stem with a hairy globose head, from which 
every day a flower opens that may vary in color from pure white to deep 
blue. The other species, G. bigelovi1, stays mostly on the slopes, and its 
slender shiny stems are taller than the species described above. Here 
and there are to be found small compact clusters of flowers like small 
white daisies borne on short stems, EHremiastrum belliodes, which also 
exhibits the marks of the desert. Finding its way about, across the mesas 
and over the hill-slopes, is the alfilerilla, Erodium cicutarium, a relative of 
the geranium, which spreads its flat rosettes of greenish laciniate leaves 
wherever it may find a foothold, and after its pinkish flowers come the 
long fruits, which sow the seeds so abundantly and efficiently that this 
plant travels by leaps and bounds. Small straight stems, clothed with 
hairy linear leaves, terminate in spikes of delicate purple flowers in 
Orthocarpus purpurascens palmeri, and single individuals occur here 
and there on the mesas, in the sand and gravel, but in some places so 
