MUSTARD FAMILY 



III 



olate, y 2 to \y 2 in. long; the upper much smaller, sessile but 

 not clasping the stem. Petals nearly white. Pods stiffly 

 erect, 1 to 2y 2 in. long, very acute. Seeds orbicular, broadly 

 winged. — In open, gravelly places from 4000 ft. to timber-line. 

 Mt. Dana is the type locality. 



4. A. holboellii Hornem. Stem usually simple below, 1 

 to 2 l / 2 ft. high, from a biennial taproot. Herbage finely pu- 

 bescent below. Basal leaves oblanceolate, mostly entire, \y 2 

 in. or less long; stem-leaves oblong or lanceolate, sessile by 

 a broad clasping base. Flowers white or purplish. Pods 

 nearly straight, V/ 2 to 3 in. long, pendent from sharply 

 deflexed pedicels, the seeds in one row. 



Although this species is sometimes confused with no. 2 and 

 no. 5, it may be known from either of them by the more 

 slender pods, which at maturity form a much narrower 

 cluster. It is common throughout the mountains except at 

 very high altitudes. A. bolanderi Wats., first described from 

 specimens gathered in "Yosemite Valley or Mono Pass," 

 seems to be only a form of this. Its only distinguishing 

 characters are the short pods, l / 2 to \y 2 in. long, and the 

 seeds somewhat in two rows. The pods, however, are exceed- 

 ingly variable as to length. 



5. A. arcuata Gray. Stem erect, 1 to 2 ft. high, from a 

 biennial or perennial tap- 

 root, rough- pubescent. 

 Lower leaves narrowly ob- 

 lanceolate, 1 or 2 in. long, 

 entire or sharply toothed; 

 stem -leaves lanceolate, 

 acutely angled and clasp- 

 ing at base. Flowers % 

 to y 2 in. long, rose-color. 

 Pods spreading, curved, 2 

 to 4 in. long; seeds in 2 

 rows in each division (in 

 only 1 row in all our other 

 species). - 



The compact, rose-pur- 

 ple flower-clusters of this Arabis may be seen anywhere in 

 the lower part of the pine belt in May or early June, soon 

 followed by the loose, dome-shaped raceme of long, recurving 

 pods. It grows as isolated plants or in small clumps, inhabit- 

 ing loose soil, especially on the slopes. 



6. A. lemmdnii Wats. Stems numerous and branching be- 



