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 ali the ecological factors that 
appiy to herbaceous plants. 
No species of Astragalus nave pecome sapropuytes, epiphytes, 
or parasites. 
A. reptans is the only species that creeps and roots. None are 
truly stoloniterous. 
Only about half a dozen species are woody and then only be- 
low such as some Inflati A. leucophyllus and the like, A. Traskie belong 
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 are fleshy more 
because of the alkaline soil. 
125 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. 
150 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 alnine species have slender underground stems or 
branching root crowns or interlacing roots forming loose putches of 
plants, particularly the Alpini, 
A. pictus and subcinereus have filiform and branching roots and 
long underground stems. A, junceus and Duchesnensis are muen 
the same but less branched. Most of the Homalobi have prostrate 
and much altered. The annuals separate into those with pods sessile 
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 
I 
