28 



ECOLOGY. 



To give the ecology of Astragalus would require the ecology of 

 the Great Plateau, altogether too great a subject for this monograph. 

 In Contributions No. 13 I went into the subject of life zones 

 pretty fully, giving the main features and the basis on which they 

 rest, and also went into the subject of barriers in their effect on the 

 distribution of species in the west. These subjects will be treated 

 briefly here. 



Astragali have to contend with all the ecological factors that 

 apply to herbaceous plants. 



No species of Astragalus have become saprophytes, epiphytes, 

 or parasites. 



A. reptans is the only species that creeps and roots. None are 

 truly stoloniferous. 



Only about half a dozen species are woody and then only be- 

 low such as some Inflati, A. leucophyllus and the like, A. Traskiae 

 belongs with the Hamosi, none are true shrubs. 



Nearly all species are tufted from vertical tap roots; none have 

 tuberous roots though some have fleshy roots, particularly those 

 growing in clay soil where it is almost impossible for annuals to 

 grow, such as the Navajo Basin. A. Musiniensis and cymboides have 

 fleshy roots, the former 3-4 feet long, the same is true of A. ascle- 

 piadoides, Pattersoni, sabulosus, but the latter afre fles|hy mcjre 

 because of the alkaline soil. 



12,5 species have woody roots. 11 species are biennial; 41 

 species are annual. 



108 species have slender stems; 131 have delicate stems; 52 

 species have coarse and stout stems. 



1.50 species have small leaves; 115 species have thick leaves; and 

 76 species have delicate leaves. 



32 species grow in meadows; 61 in forests; and 112 in shade of 

 brush or other plants; 120 are low plants; 38 species grow in sweet 

 soil; 59 in alkaline soil strongly impregnated. 



205 species have bladdery pods; 114 fleshy pods; and 144 have 

 colored or blotched pods; none of the pods are truly edible. 



128 species have small flowers; 133 large flowers; 7 coarse 

 flowers; 24 delicate ones; 104 inconspicuous ones; 173 bloom in 

 spring; 99 mature in two months, the rest in 2-3 months; 210 have 

 white or cream-colored flowers. 



Most of the alpine species have slender underground stems or 

 branching root crowns or interlacing roots forming loose patches of 

 plants, particularly the Alpini, 



A. pictus and subcinereus have filiform and branching roots and 

 long underground stems. A. junceus and Duchesnensis are much 

 the same but less branched. Most of the Homalobi have prostrate 

 and much interlaced csespitose stems. A. argcphylhis is much 

 the same but stems coarser and woody. Many of the Great Basin 

 species have stems with bark performing the duties of leaves, and 

 leaflets reduced to phyllodia or very narrow. The annual species 



