70 CRUCIFERiE. (mustard FAMILY.) 



Oil slender pedicels, linear and narrow, bringing the seeds into one row; stijle 

 verij short. — AVet meadows, Mass. to Va. ; rare. (Nat. from Eu.) 



1. N. sinuatum, Kutt. Stems low, diffuse; leaves phmatel)/ cleft, the 

 short lobes nearly entire, linear-oblong; pods linear-oblong (4-6" long), on 

 slender pedicels; sti/le slender. — Banks of the Mississippi and westward. 

 June. 



* * Annual or biennial, rarely perennial {?), with simple Jihrous roots; flowers 

 small or minute, greenish or yellowish ; leaves somewhat lyrate. 



2. "N. sessiliflorum, Nutt. Stems erect, rather simple ; leaves obtusely 

 incised or tootlied, ubovate or ohlong; flowers minute, nearly sessile; pods 

 elongated-oblong (5-6" long), thick; style very short. — W. 111. to E. Kan., 

 Tenn., and southAvard. April -June. 



3. N. obtusum, Kutt. Stems much branched, diffusely spreading; 

 leaves pinnately jjaried or divided, the divisions roundish and obtusely toothed 

 or repaud ; flowers minute, short-pedicelled ; pods longer than the pedicels, vary- 

 ing from linear-oblong to short-oval; style short. — With n. 1 and 2. 



4. N. palustre, BC. (Marsh Cress.) Stem erect; leaves pinnately 

 cleft or parted, or the upper laciuiate ; the lobes oblong, cut-toothed ; pedicels 

 about as long as the small flowers and mostly longer than the oblong, ellipsoid, 

 or ovoid pods; style short. — Wet places or in shallow water; common. 

 June -Sept. — Elowers only l-l|^"loug. Stems 1-3° high. — The typical 

 form with oblong pods is rare. Short pods and hirsute stems and leaves are 

 common. Var. ufspiDUM is a form with ovoid or globular pods. (Eu.) 



§3. Petals white, much longer than the calyx; pods ovoid or globular ; leaves 

 undivided, or the lower ones pinnatifld ; root perennial. 



5. N. lacdstre, Gray. (Lake Cress.) Aquatic; immersed leaves 1-3- 

 piuuately dissected into numerous capillary divisions ; emersed leaves oblong, 

 entire, serrate, or piuuatifid; pedicels Avidely spreading ; pods ovoid, \-cel led, 

 a little longer than the style. — Lakes and rivers, N. E. New York to N. J., 

 Minn., and southwestward. July -Aug. — Near N. amphibium, 



N. ArmorAcia, Fries. (Horseradish.) Root-leaves very large, oblong, 

 crenate, rarely pinnatifld, those of the stem lanceolate; fruiting pedicels as- 

 cending; pods globular (seldom formed); style very short. (Cochlearia Armo- 

 racia, L.) — Roots large and long; a well-known condiment. Escaped from 

 cultivation into moist ground. (Adv. from Eu.) 



12. BARB ARE A, R. Br. Winter Cress. 



Pod linear, terete or somewhat 4-sided, the valves being keeled by a mid- 

 nerve. Seeds in a single row in each cell, marginless. Cotyledons accum- 

 bent. — Mostly biennials, resembling Nasturtium; flowers yellow. (Anciently 

 called the Herb of St. Barbara.) 



1. B. vulgaris, R. Br. (Common Winter Cress. Yelloav Rocket.) 

 Smooth ; lower leaves hrate, the terminal division round and usually large, 

 the lateral 1-4 pairs or rarely wanting ; upper leaves obovate, cut-toothed, or 

 pinnatifld at the base ; pods erect or slightly spreading ; or in var. stricta, 

 appressed ; in var. arcuXta, ascending on spreading pedicels. — Low grounds 

 and roadsides ; apparently introduced, but indigenous from L. Superior north- 

 ward and westward. (Eu.) 



