70 CRUClFERiE. (mustard FAMILY.) 



on slender pedicels, linear and narrow, bringing tlie seeds into one row , style 

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



1. TS. sinuatum, Nutt. Stems low, diffuse; leaves pinnately cleft, the 

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

 slender pedicels ; style slender. — Banks of the Mississippi and westward. 

 June. 



* * Annual or biennial, rarely perennial (?), with simple Jibrous roots; Jiotcers 

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



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

 incised or toothed, obovate or ohlong ; Jloicers minute, nearly sessile; pods 

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

 Tenn., and southward. April -June. 



3. N. obtUSUm, Xutt. Stems much branched, diffusely spreading, 

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

 or repand ; Jloicers 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. pallistre, E)C. (Marsh Cress.) Stem erect; leaves pinnately 

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

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

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

 June -Sept. — Flowers only l-l|"long. Stems 1-3° high. — The typical 

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

 common. Var. hispidum 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 pinnatijid ; root perennial. 



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



pinnately dissected into numerous capillary divisions ; emersed leaves oblong, 



entire, serrate, or pinnatifid ; pedicels widely spreading ; pods ovoid, 1-celled, 



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



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



IsT. Armoracia, Fries. (Horseradish.) Root-leaves very large, oblong, 

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

 cending; pods g/obidar (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. BAR BARE A, R.Br. AVixter Cress. 



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

 nerve. Seeds in a single roAv in each cell, margiuless. Cotyledons accum- 

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

 called the Herb of St. Barbara.) 



1. B. vulgaris, R. Br. (Co.mmon Winter Cress. Yellow Rocket.) 

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

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

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

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

 and roadsides ; a]>])arently introduced, but indigenous from L. SujDcrior north- 

 ward and westward. (Eu.) 



