Thlaspi. CRUCIFERiE. 113 



P. scapigerum (Hook. 1. c.) 



On rocks at the Great Falls of the Oregon, Douglas. March-April. — 

 Leaves runclnate-pinnatifid, attenuate at the base, glabrous. Scapes nume- 

 rous, 3 inches high. Petals white. Seeds about 4 in each cell, roundish. 

 Funiculi rather long and slender. Hook. 



31. SUBULARIA. Lin«. ; DC. ; Hook. fi. Land. (n. ser.) t. 135. 



Silicle oval ; valves turgid : cells many-seeded. Stigma sessile. " Cotyle- 

 dons linear, curved." Hook. — A small stemless aquatic plant. Leaves 

 linear-subulate. Scapes few-flowered : flowers white. 



S. aquatica (Linn.)— />C. prodr. 1. p. 235 ; Hook. I. c. f Brit. fl. 

 p. 299. 



Borders of ponds Maine, NuttalU—H Scape 1-2 inches high. Flowers 

 minute : pedicels slender. Silicle a line and a half long. — According to 

 Hooker, the cotyledons are not biplicate as they are described by De Can- 

 doUe, but are curved or folded in such a manner that their base occupies a 

 portion of the radiclar side of the curvature. 



Tribe VIL THLASPIDEiE. DC. 



Silicle dehiscent, compressed contrary to the very narrow septum ; 

 valves boat-shaped. Cotyledons plane, accumbent, contrary to the 

 septum. 



32. THLASPL Dill; DC.syst.2. p. 373. 



Silicle emarginate at the apex ; valves winged on the back ; cells 2- or 

 many-seeded. Petals equal. Calyx equal at the base. — Flowers white. 



1. 71 arrense (Linn.): leaves oblong, toothed ; silicles orbicular-obovate, 

 shorter than the pedicels; style scarcely any. — Pursh, Jl. 2. p. 435; DC. 

 prodr. 1. p. lib ; Hook. fl. Bor.-Am. 1. p. 58. 



Canada; New-York to Pennsylvania, Pwrs/j ; Michigan, Nuttall. In- 

 troduced. June-July. — Cauline leaves somewhat sagittate ; auricles minute. 

 Valves of the silicle much compressed, furnished with a conspicuous wing. 



2. T. alliaceum (Linn.) : leaves oblong, obtuse, somewhat toothed ; the 

 upper ones sagittate-clasping, with acute auricles ; silicles ovate-ventricose ; 

 stigma nearly sessile. — DC. prodr. 1. p. 176 ; Nutt. gen. 2. p. 65. 



Cultivated fields, scarcely naturalized. — Flowers smaller than in T. ar- 

 vense. 



3. T. montanum (Linn.) : leaves rather fleshy, entire ; radical ones ob- 

 ovate, petioled ; cauhne ones oblong, sagittate-clasping; petals longer than the 

 calyx; silicles obcordate, 4-seeded ; style filiform. DC. prodr. \. p. 176; 

 Hook.fl. Bor.-Am. \.p. 58. 



Arctic America and Canada, ex Hook. May-July. — U . 



4. T. cochleariforme (DC.) : leaves rather fleshy ; radical ones petioled, 

 ovate or obovate, somewhat toothed or entire ; cauline ones oblong, cordate- 

 clasping ; petals longer than the calyx ; silicles obovate, emarginate, 8-seeded. 



15 



