198 THE PLANT WORLD 



more prominent may be mentioned. 



Astragalus )ittttaU'ui)iiis, an innocuous relative of the 

 "loco' weed, ripens its curved reddish pods early in March 

 and scatters the seeds in the gravel, the small stems withering 

 away long before the summer comes. Streptanthits arizon- 

 irus, 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, HarpagoiicUu pa/iiicri and Pcclocaryci luwaris, 

 occupy the most prominent place in this group of plants, the 

 soil being generallv so thickly snwn with their seeds that the 

 rains br'ng up a dense carpet of these plants; e\erv square inch 

 of available space on Tumamoc Hill is occupied with their 

 short, hairv stems, the burs being quickh' matured, and in the 

 dry weeks of April forming an unpleasant feature of a walk 

 off the trail. Plantagos abound: PIcuilago spUinlosa stays 

 on the steeper slopes, while P. igiiola is abundant o\-er \-ast 

 areas of gra^•elly or sandy mesa, the silverv, hairv and grayish 

 appearance of the leaves being such that it is difficult to deter- 

 mine at a glance whether the plants are ali\"e or dead. Of the 

 annuals, these two are furnished with the structures most gen- 

 erally characteristic of forms that live in drv places. PJiaci'lia 

 lauacetifuUa, with its scorpoid inflorescence, is scattered 

 among the rocks and on the slopes over a wide range, and as 

 it cioes not bloom until well on with the coming dry weather, 

 it and its neighbor, Anisinck'ui iiitcnut'dia, \\\t\\ yellow flow- 

 ers, ha^•e some of the features of desert plants. Early in 

 April, shining silvery balls of fruit, reminiscent of the dande- 

 lion, are met frequently, and these prove to be relati\'es of that 

 weed, being Microscris Ihicarifolla, with erect linear lea\'es 

 around the scape which bears the fruit, and Rafiiicsqiiia iico- 

 wf.v/rV7//^/withshorterlaciniateleaveson its thicker stems. The 

 wild carrot. Damns piisilhis, holds its umbels of inconspicu- 

 ous flo\Aers but a few inches abo\e the ground, and these ripen 

 seeds in April, when the entire plant quickly dries up. Bo-zv- 

 lesia lohala is abundant in certain localities, while two gilias, 



