62 



SisyniDriuni canescens Nnfct. — A slender, branching mustard with yellow flowers; 



the most abundant mustard in the desert, sometimes f'ormini;' considerable fields 



of yellow among the sage-brush on sandy slopes, or in the draws. Point of 



Rocks, June 1 (3078); Wamsntter, June 4 (3126). 

 Sisymbrium liuifolium Xutt. — A mustard with slender stems, simple or several 



from the base; leaves entire or nearly so, smooth. Verj^ abundant in many 



places throughout southern Wyoming. Wamsutter, June 4 (3127). 

 Physaria sp. ( ? ). — A small, leafy perennial of the double bladder-pod crucifers. 



Kather abundant on the dry shale cliffs. Green River, May 30 (.3032). 

 Bursa bursa-pastoris Britton (Shepherd's Purse). — This was noted in several 



places along tlie railroad. 

 Draba glacialis Adams (Whitf.ow-cras.s). — A small, tufted crucifer, scarcely more 



than 1 inch high. Green River, June 1 (3071). 

 Arabis cauescens Nutt. (Ashy Rock-cress). — A slender, sparingly branched ])er- 



eanial, about 1 foot high, conmion in some sandy draws among the sage-brush. 



Point of Rocks, .lune 1 (3077). 

 Arabis brebneriana A. Nels. (Brkrner's Rock-cress). — A form rare in the locality. 



Fort Steele, June 5 (3135). 

 Streptanthus longirostris Wats. — Sparingly branched, from 1 to 2 feet high ; fre- 

 quent ou the san<ly river bottom. Green River, May 31 (3040) ; Point of Rocks, 



June 1 (3082). 



CAPPARIDACE^. 



Cleome lutea Hook. (Yellow Cleome). — An erect, glabrous, somewhat branched 

 lierl), 1 to 2 feet high, tlowers yellow, and the pod borne on a long, slender stipe. 

 Abundant on the sandy bottoms. Green River, May 31 (3046). 



SAXIFRAGACEiE. 



Heuchera parvifolia Nutt. — Perennial from a thick root, with a rosulate cluster of 

 root-leaves ami slender leafless stems, bearing sliort spike-like jtanicles of small 

 flowers, 9 to 18 inches high. Infrequent; on tlie slopes below the winter snow- 

 drifts. South Butte, .luly 13 (3.540). 



Philadelphus occidentalis A. Nels. (Western Syringa). — A branched shrub, 3 to .5 

 feet high, peculiar to dry, desert canyons. It was an agreeable surprise to find 

 a clump of this syringa iu one of the canyons near Rock Springs, July 15 (3595). 



ROSACEiE. 



Holodiscus dumosus TTeller. — A branched shrub, 2 to ."> feet high; very rare within 

 the borilers of tlic desert; only below the permanent Avinter snowdrifts. South 

 Butte, July 13 (3536). 



Potentilla glandulosa Lindl. (Glandclar Cinquefoil). — A handsome perennial 

 plant, some 18 to 30 iu(;hes high, sparingly branched; flowers yellow. Only on 

 moist slopes below snow banks. South Butte, .July 13 (3534). 



Potentilla anserina L. (Silver-weed). — A tufted, spreading plant, common on wet, 

 saline soil everywhere in the desert as well as elsewheie iu the State. 



Gaum macrophyllum Willd. (Lar(;i:-leai"ED Avens). — A ptjrennial herb, a foot or 

 two in height, sometimes l)ranched above, with large, lobed root-leaves ou long 

 ])etioles. Infrequent; on the moist slopes below the winter snow lianks. South 

 Butte, .luly 13 (3.543). 



Cercocarpus parvifolius H. & A. (Mountain Mahoc.anv). — A stiff, scraggy shrub, 

 3 to 6 feet liigh; common on rocky slo])e.s throne iiout the southern part of the 

 State. Observed in several i)lace8 in the desert ou the vviuter snow slopes. 



