CRUCIFERAE. 169 



narrow partition, the 2 cells indehiscent, strongly wrinkled, 

 each 1-seeded. 



Pods notched at the apex, wrinkled. C. didymus. 



Pods not notched at the apex, tubercled. C. coronopus. 



Coronopus didymus (L.) Smith. Sparsely pubescent; stems branched, 

 spreading, 5-30 cm. long; leaves pinnately parted into narrow entire or lobed 

 segments, the lower ones petioled; pods 2 mm. broad, about two thirds as long, 

 notched at the apex, the surface finely wrinkled. 



Sparingly introduced from Europe. 



Coronopus coronopus (L.) Karst. Glabrous or a little pubescent; leaves 

 similar to those of C. didymus, mostly less divided; pods coarsely rugose, not 

 notched at the apex. 



Native of Europe, introduced with ballast. 



218. ATHYSANUS. 



Slender annual herbs, usually branching at the base, with a 

 pubescence of branched hairs; flowers minute, in racemes; petals 

 small, white, or none; style short; ovules 3-4, only one maturing; 

 pod orbicular, indehiscent, not margined, nerveless, 1-celled, 

 1-seeded. 



Athysanus pusillus (Hook.) Greene. Stems slender, branched from the 

 base, 10-20 cm. tall, hirsute-pubescent throughout; leaves oblong-lanceolate, 

 acute, usually coarsely dentate, rough-pubescent, 5-30 mm. long; racemes 

 loose, elongate; flowers very small, on curved pedicels; petals linear, minute 

 or wanting; pods orbicular, about 2 mm. in diameter, hirsute, on recurved 

 longer pedicels. 



Gravelly prairies and rocky slopes, rare west of the Cascade Mountains 

 but common in the interior. 



219. THYSANOCARPUS. 



Erect and slender sparingly branched annual herbs, with a 

 pubescence of simple hairs; flowers minute, white or rose-colored, 

 in elongated racemes; pod mostly pendulous, on a slender pedicel, 

 1-celled, indehiscent, disk-shaped or concave, orbicular, winged, 

 1-seeded; seed flattened but not winged. 



Thysanocarpus curvipes Hook. More or less hirsute below, glabrous above; 

 stem erect, usually branched above, 30-50 cm. tall; radical leaves oblong, 

 obtuse, dentate, 3-4 cm. long, narrowed at base, with a petiole; cauline sagit- 

 tate and clasping at base, acute, usually entire, commonly smaller; racemes 

 elongated, loose; pedicels slender, recurved; pods orbicular, ovate or obovate, 

 notched, apiculate by the persistent style, puberulent, 4-6 mm. long, the entire 

 or crenulate wings as broad as the body. 



In dry open ground, Victoria, British Columbia, Macoun; Willamette 

 Valley, Oregon. Not known from western Washington. 



220. ARABIS. Rock Cress. 



Erect annual or perennial herbs; leaves seldom divided, the 

 cauline sessile and usually clasping and auricled at the base; 



