14 
the remaining 4), and a long or short pod, which is usually 2 celled by 
a thin partition which bears the seeds, and from which the valves sepa- 
rate when ripe (in one group the pods indehiscent and continuous or 
jvinted).—No attempt should be made to name the plants of this fam- 
ily without mature pods. The following generic key is artificial : 
1. Pod 2-celled, dehiscent by * valves. 
* Pod terete, turgid, or 4 angled. 
+ Pod long-linear (2.5 to 10 cm.): seeds in 1 row. 
4+ Valves 1-nerved (except one species of Thelypodium). 
1. Thelypodium. Flowers white or rose-color: anthers sagittate at base, curved: 
pod terete or nearly so: stigma mostly entire. 
2, Erysimum. Flowers yellow : anthers sagittate, not coiled; pod 4-angled: stigma 
2-lobed. 
a+ + Valves 3-nerved. 
3. Dryopetalon. Petals white and pinnately lobed: pod terete and very slender: 
leaves runcinate. 
One species of Thely podium may be looked for here. 
+ + Pod linear, shorter (mostly less than 2.5 cm. long), nearly terete: valves 1 to 3- 
nerved: seeds in 1 row (except in one species of Sisymbrium): flowers yellow or 
white. 
4. Brassica. Pod with a long stout beak: seeds globose. 
5. Sisymbrium. Pod short-pointed or obtuse: seeds oblong: mostly annials, 
with toothed or finely dissected leaves. 
_ + + Pod oblong-cylindric to globose: valves strongly convex, nerveless : seeds 
in 2 rows. 
6. Nasturtium. Pod oblong or short-linear: flowers white or yellow: smooth or 
somewhat hispid. 
7. Lesquerella. Pod globose (in ours) : flowers mostly yellow: with stellate often 
dense pubescence. 
** Pod flattened parallel to the broad partition. 
+ Pod short: flowers white or yellow. 
8. Draba. Pod ovate to oblong or linear: low plants with racemose flowers. 
+ + Pod elongated: flowers white to purple. 
9, Arabis. Anthers short, scarcely emarginate at base: petals with a flat blade 
and claw: calyx short or narrow, rarely colored. 
10. Streptanthus. Anthers elongated, sagittate at base: petals more or less 
twisted or undulate, the claw channeled: calyx dilated and usually colored. 
»** Pod more or less flattened contrary to the narrow partition. 
+ Pod linear, becoming elongated (2.5 em. or more) and more or less arcuate : flowers 
white or purple. 
11. Greggia. Low stellately pubescent plants, with rather large flowers and pubes- 
cent pods. 
+ + Pod short, from oblong to orbicular. 
++ Flowers white. 
12. Capsella. Pod obcordate or oval, many-seeded : nearly smooth or pubescent 
annuals. 
13. Thlaspi. Pod cuneate-oblong, with sharply keeled valves, and cells 2 to 4- 
seeded: smooth alpine perennial with entire or toothed leaves. 
14. Lepidium. ,Pod orbicular or obovate, 2-winged at the summit, aud cells 1 or 
2-seeded. 
++ ++ Flowers purple or yellow (rarely white). 
