CRUCIFERAE (MUSTARD FAMILY) 225 



of segregation as they run hopelessly into each other: S. intermedia Rydb. 

 Mem. N. Y. Bot. Card. 1: 184. 1900; S. purpurascens Rydb. Bull. Torr. Bot. 

 Club 31: 556. 1904; S. ramosa Rydb. 1. c.; S. viscosa Rydb. 1. c. 29: 238. 

 1 902. Throughout the western half of the United States. 



4. Sophia pinnate (Walt.) Brit. Mem. Torr. Club 5: 173. 1894. Canes- 

 cent with short branching hairs: stems 2-8 dm. high, more or less branched: 

 leaves once or twice pinnate; the segments more or less deeply pinnatifid or 

 toothed: siliques acute at each end, and pointed with the very short style, 

 usually shorter than the slender spreading pedicels: seeds in 2 rows. S. 

 canescens. Common throughout our range; nearly across the continent; 

 quite variable. 



5. Sophia leptophylla Rydb. Bull. Torr. Bot. Club 29: 239. 1902. Spar- 

 ingly glandular, 4-7 dm. high: leaves very thin, green, only once pinnate; 

 segments of the lowest leaves rounded; those of the middle lanceolate and 

 somewhat incised; the upper segments entire: pedicels slender, in fruit 5-8 mm. 

 long, spreading; silique linear, 8-10 mm. long, much less than 1 mm. wide, 

 torulose, spreading, upwardly curved: seeds uniseriate. From eastern Wy- 

 oming to Montana. 



6. Sophia ochroleuca Wooton, Bull. Torr. Bot. Club 25: 455. 1898. Cin- 

 ereous-tomentulose, with close branching hairs, 5-7 dm. high: leaves pinnatifid 

 or dissected; the segments small, oblong to linear: petals cream- white or pur- 

 plish: silique terete, 8-10 mm. long, ascending, as is also the subequal pedi- 

 cel : seeds in 2 rows. (The following seem too near to be clearly distinguished : 

 S. halictorum Ckll. Bull. Torr. Bot. Club 25: 460. 1898; S. andrenarum Ckll. 

 1. c. 28: 48. 1901.) Southern Colorado and New Mexico. 



22. STENOPHRAGMA Celak. 



Annual or biennial herbs with the aspect of some species of Arabis; pu- 

 bescence branched. Stems simple or branched, with entire or dentate leaves. 

 Flowers small, white, in terminal racemes. Silique linear; valves convex, 

 nerveless; style short; stigma entire, 2-lobed. Seeds in one or two rows. 

 Sisymbrium in part. 



1. Stenophragma virgata (Nutt.) Greene, Pitt. 3: 138. 1896. Cinereous or 

 tomentose with branched hairs, biennial, 1-4 dm. high: stem simple or freely 

 branched from the base: radical leaves rosulate, oblong, entire, or toothed, 

 petioled, 3-6 cm. long; cauline entire, sagittate-clasping: siliques 20-30 mm. 

 long, erect, on spreading pedicels about one third as long. Sisymbrium vir- 

 gatum. (Arabis Brebneriana A. Nels. Bull. Torr. Bot. Club 25: 373. 1898.) 

 Frequent, moist banks and slopes; southern Wyoming. 



23. ARABIS L. 



Annual, biennial, or perennial herbs, glabrous or pubescent, with entire, 

 toothed, or pinnatifid leaves, and white, rose-colored, or purple flowers. Siliques 

 long-linear, compressed, with 1-nerved valves, dehiscent at maturity; 'stigma 

 nearly entire or 2-lobed. Seeds in 1 or 2 rows in each cell, flattened, winged, 

 or wingless; cotyledons accumbent. 



Cauline leaves wholly glabrous, at least the uppermost; basal leaves 



more or less pubescent. 

 Mature siliques erect or nearly so. 



Stems hirsute at base 1. A. glabra. 



Stems glabrate at base. 



Seeds broadly winged, in 2 rows . . . . . . 2. A. Drummondii. 



Seeds narrowly winged, in 1 row 3. A. Lyallii. 



Mature siliques widely spreading. 



Straight and long (4-6 cm.) . . . . . . 4. A. divaricarpa. 



Curved or else short (2-3 cm.). 



Leaves all entire, linear or nearly so. 



Plants low (5-20 cm.); silique short (less than 3 cm.). 

 Sepals pubescent. 



Basal leaves dentate, thin . . . . . . 5. A. recondita. 



Basal leaves entire, thick . . , , , . 6. A. Lemmonii. 



ROCKY MT. BOT. 15 



