88 



Descriptive Flora 



grounds and dry hillsides. Rarely noticed. Distinguished from 

 Draba platycarpa by the very small branched hairs that cover 

 the plant (use magnifying glass.) 



Draba platyoarpa Torr. & Gray. Whitlow Grass. Draba. 



Similar to the preceding species but plant is hairy (but 

 hairs are not branched), and pods are wider and shorter 

 (6 — 7.5 mm). Not as common as the above species. 



Arabis petiolaris A. Gray. Rock Cress. 



Flowers white or deeply tinged with purple, in a loose cluster 

 at the end of tall, simple, swaying stems that are smooth or 

 covered with reflexed hairs. Basal leaves few, 4 to 8" long, with 

 five to seven lobes. Stem leaves alternate, various, upper entire, 

 lower pinnatifid or halberd-shaped. Petals four, purplish. 

 Stamens six, two short, four long. Pod flat, erect, or ascending, 

 2 to 3 inches long and containing many flat seeds. March to 

 June. Widespread. Genus is named for Arabia. 



Sophia pinnata (Walt.) Britton. Tansy Mustard 



(Sisymbrium canescens Nutt. ) 



Plants with small, flat-topped clusters of greenish yellow 

 flowers, much divided, finely cut, once or twice pinnately com- 

 pound leaves, and 4-sided pods about y± long, that form up the 

 stem as the plant continues to blossom. Petals 4. Stamens 6, 

 4 long, 2 short, exceeding the minute petals. Seed pods peppery, 

 14" long, on slender, ascending stalks *4 to y 2 " long. Leaves 

 1 to 2" long, once or twice pinnately compound. Leaflets finely 

 divided and lobed. 



CAPP ARID ACE AE . Caper Family. 



Polanisia imchysperma Torr. & Gray. Clammy-weed. 



Spider Flower. 



Hairy, clammy weeds with a disagreeable odor. Leaves 

 compound, alternate, trifoliolate. Leaflets entire, V2 — long- 

 Flowers in terminal clusters with small leaflike bracts crowded 

 on the stem below. Sepals four. Petals four, white, broad above 



