CKUCIFERAE (kUSrARD FAklLY) 229 



siliques glabrous, linear, somewhat curved, reflexed or pendent, on short 

 widely spreading pedicels: seeds in 1 irregular row. — On naked limestone 

 slopes; southeastern Wyoming to Colorado. 



21. Arabis Fendleri (Gray) Greene, Pitt. 3: 156. 1897. Related to the 

 foregoing, with similar pubescence: stem mostly solitary, erect, 3-5 dm. high, 

 glabrous above: basal leaves few, oblanceolatCj similar to the lower cauline 

 which are equably distributed, with hirsute-cihate and scattered trifurcate 

 hairs, tapering to a slender petiole, rarely 3 cm. long; the upper cauline re- 

 duced, glabrous, auriculate-clasping: siliques as in the preceding but longer: 

 seeds in 2 rows.^-Colorado to New Mexico. 



22. Arabis caduca A. Nels. Biennial, maturing early the second season and 

 then quickly disintegrating: stems solitary from a taproot, erect, thick but 

 brittle, branched above, hiraute with branched hairs at base only: basal leaves 

 rosulate, early caducous, oblanceolate, petioled, 2-3 cm. long, rough with a 

 branched hirsute pubescence; cauline oblong or broadly linear, sessile by an 

 auricled base, glabrous: flowers small; racemes becoming very long, rather 

 crowded: siliques l-nerved to the middle, broadly linear, straight, acute, gla- 

 brous, 5-7 cm. long, pendent on reflexed pedicels, or more usually on pedicels 

 sharply refracted at their base: seeds in 2 rows. A. Holboellii in part.-— Sandy 

 slopes and plains; southern Wyoming, south and west to Utah. 



23. Arabis lignipes A. Nels. Bot. Gaz. 30: 191. .1900. Shor,t lived peren- 

 nial: stem usually solitary, virgate, and simple (rarely 2 or 3 from the crown), 

 3-5 dm. high, cinereously stellate-pubescent below (often only the raceme 

 glabrous), Ugnescent at base, a short portion persistmg each year (for 2 or 

 3 years) and this part crowned with a rosulate cluster of leaves, from among 

 which rises, proliferous, the next year's stem: lower leaves oblanceolate-linear, 

 cinereous-stellate, subpetioled, 2-4 cm. long; upper cauline sessile, auriculate, 

 lanceolate, often glabrous; raceme long and narrow: sepalg purplish, scarious- 

 margined, exceeded by the white or pale petals: siliques very slender, curved, 

 becoming 6 cm. or more in length, pendent on slender pedicels, usually 

 sharply refracted: seeds in 1 row. — From northern Wyoming to U]tah. 



24. ArabisligniferaA. Nels. Bull. Torr.Boti Club 26: 123. 189^." Branched 

 from the base and decidedly woody-persistent, 3-5 dm. high: aiinual stems 

 several, assurgent or erect, simple or branched, substellate below, glabrous 

 above: leaves finely stellate, mostly basal, on short sterile branchlets, oblong- 

 oblanceolate, petioled, 3-5 cm., long;. cauline from oblong to lanceolate, short- 

 auriculate: raceme simple or branched, nearly or quite glabrous: petals white 

 or pinkish, twice as long as the obtuse gcaridiis-margined.. sepals: siliques. 

 linear, 3-4 cm. long, from widely divaricate to pendulpus ; the valves 1-neryed : 

 seeds uniseriate, as broad as the valves, narrowly, winged. — Aridcafion-sides; 

 southwestern Wyoming to Colorado and Utah. 



25. Arabis Selbyi Rydb. Bull.. Torr. Bot. Club 31: 257. 1904. Perennial 

 with a basal rosette of oblanceolate, acute, sinuate-denticulate, short petioled 

 leaves, 5-10 cm. long and green but stellate on bpth sides: stems branched, 

 4-5 dm. high: cauline leaves linearrlanceolate, sagittate at the base: raceme 

 long and lax: sepals linear, sparingly stellate: petals red-purple, long-clawed: 

 silique divergent, broadly linear, 3 cm. long, on short divergent pedicels: 

 seeds in 2 rows.— -Southwestern Colorado. 



26. Arabis eremophila Greene, Pitt. ,4: 194. 1900. Perennial, the herbage 

 cinereous with a rather dense branched pubescence: stems several from the 

 base, ascending, 1-3 dm. long: leaves mostly basal, oblong-lanceolate, sa- 

 liently denticulate, petioled; cauline few, linear, wjth short and inconspicuous 

 auricles: petals rose-red, small: siliques narrowly linear, 3-4 cm. long, spread- 

 ing, on slender pedicels nearly half as long: seeds in 1 row.--— Southern Col- 

 orado to New Mexico and Arizona. 



24. ERYSIMUM L. Western Wallflower 



Biennials or perennials, with short h^rsh pubescence of branched hairs, 

 alternate, entire or toothed leaves (not clasping at base), and flowers generally 



