164 



CRUCIFERAE 



Vol. II. 



I. Neobeckia aquatica (Eaton) Britton. Lake 

 Water-cress. River-cress. Fig. 2036. 



Cochlearia aquatica Eaton, Man. Ed. s, i8i. 1829. 



N asturtium natans var americanum A. Gray, Ann. Lye. N. 



¥.3:223. 1836. 

 Nasturtium lacustre A. Gray, Gen. III. i : 132. 1848. 

 Roripa americana Britton, Mem. Torr. Club 5: 169. 1894. 

 Neobeckia aquatica Greene, Pittonia 3 ; 95. 1896. 

 Radicula aquatica Robinson, Rhodora 10: ^2, 1908, 



Branching, i°-2° long. Immersed leaves 2'-6' long. 

 pinnately dissected into numerous fdiform divisions; 

 emersed leaves lanceolate to oblong, obtuse or acute, 

 i'-3' long, entire, serrate or lobed, readily detached 

 from the stem; pedicels j"-4" long, slender, spreading 

 or ascending; petals longer than the sepals; style about 

 1" long; pods 2" long. 



In lakes and slow streams, Quebec and Ontario to north- 

 ern New York, Minnesota, south to Florida and Louisiana. 

 Local. Summer. 



17. LEPIDIUM [Tourn.] L. Sp. PL 643. 1753. 



Erect, or rarely diffuse, glabrous or pubescent herbs, vv'ith pinnatifid lobed or entire leaves 

 and racemose white or whitish flowers. Pubescence, when present, of simple hairs. Stamens 

 often fewer than 6. Petals short, sometimes none. Silicles orbicular to oblong or obovate, 

 flattened contrary to the partition, mostly emarginate, winged or wingless; valves keeled, 

 dehiscent. Seeds solitary in each cell, pendulous, flattened; cotyledons incumbent or rarely 

 accumbent. [Greek, a little scale, from the flat scale-like pods.] 



About 65 species, widely distributed. In addition to the following, about i6 others occur in 

 western North America. Called indifferently Cress, Pepperwort or Pepper-grass. Type species : 

 Lepidium latifolium L. 



Stem-leaves clasping by an auriculate base. 



Pods broadly ovate, winged; annual or biennial, i, L. campestre. 



Pods wingless, broader than long; perennial. 2. L. Draba, 

 Stem-leaves petioled or sessile, not clasping. 



Pods and seeds entirely wingless ; petals none ; cotyledons incumbent. 3. L. ruderale. 

 Pods slightly winged above, orbicular or oval, about i" broad; petals present or none. 



Cotyledons accumbent ; petals generally present. 4. L. virginicum. 



Cotyledons incumbent ; petals minute or wanting. 5. L. densiflorum. 



Pods oblong, winged all around, longer than wide, about 2" high. 6. L. sativum. 



I. Lepidium campestre (L.) R.Br. Field, Cow or Bastard Cress. Fig. 2037. 



Thlaspi campestre L. Sp. PI. 646. 1753. 



L. campestre R. Br. in Ait. f. Hort. Kew. 4 : 88. 1812. 



Annual or biennial, erect, io'-i8' high, branch- 

 ing above, hoary-pubescent with scale-like hairs 

 or rarely nearly glabrous. Basal leaves oblong, 

 or spatulate-oblong, entire, or pinnatifid in the 

 lower part, obtuse, petioled, 2'-^' long; stem- 

 leaves oblong or lanceolate, entire or slightly 

 dentate, sessile, clasping the stem by an auricled 

 base ; flowers white or yellowish ; pedicels rather 

 stout, spreading, 2"-4" long in fruit ; pods very 

 numerous, forming dense elongated racemes, 

 broadly ovate, slightly curved upward, about 

 equalling their pedicels, or shorter, broadly 

 winged at the apex, rough, notched, tipped with 

 a minute style. 



In fields and waste places. New Brunswick and On- 

 tario to Virginia, Kansas, and on the Pacific Coast, 

 a bad weed in the Middle States. Naturalized from 

 Europe. May-July. Yellow seed. Mithridate mus- 

 tard. Glen-, or poor-man's-pepper. Glen- or crowd- 

 weed. False flax. English pepper-grass. 



