Streftanthds. CRUCIFER^. 75 



tute of a style, the fruit is not elliptical, and the leaves are more divided."— 

 Nutt. 



15. A': natans (DC.) : emersed leaves oblong-linear, entire ; immersed ones 

 many-parted Avith capillary segments ; petals scarcely longer than the calyx; 

 siliques obovate-globose. DC. syst. 2. p. 198 ; Ddess. ic. 2. t. 15. 



p. Americamim (Gray) : emersed leaves serrate ; petals (white) twice as 

 long as the calyx; siliques obovate; style as long as the ovary, and half as 

 long as the fruit.— 6>a?/ .'. in mm. lye. New- York, 3. p. 223. N. natans, 

 Hook.fi. Bar. 'Am. \.p. 39; Beck, hot. p. 32. 



y. brevistylum: emersed leaves oblong-lanceolate, denticulate-serrate ; style 

 much shorter than the ovary. 



/?. In water; Canada, Dr. Holmes'. Oneida Lake, Gray! Ogdensburgh, 

 New-York, Dr. Crawe! Pekin, Illinois, Mr. Buckley! y. near New- 

 Orleans, />. Installs! Julv.— Stem 2-5 feet long, according to the depth of 

 the water.' Submersed leaves deciduous. Flowers more than twice as large 

 as in N. paluslre. Silicle more than 2 lines in length, sometimes obovate- 

 oblong. Style slender; stigma capitate.— It is quite possible that the Ame- 

 rican plant is distinct from the Siberian species, which we know only from 

 the description of De Candolle and the figure of Delessert, and which is said 

 to have yellow flowers, smaller than those of N. amphibium, and petals 

 scarcely longer than the calyx; whereas the petals are pure white in our 

 plant, about twice the length of the calyx, and the flowers twice as large as 

 in Delessert's figure. 



3. BARBAREA. R. Br. in hort. Kew. (ed. 2.) 4. p. 109 ; DC. syst. 



2. p. 205. 

 Silique ancipital or 4-sided ; valves concave-carinate. Seeds in a single se- 

 ries. Sepals equal at the base.— Leaves lyrately pinnatifid. Flowers yellow. 



1. B. vulgaris (R. Brown) : lower leaves lyrate, the tenninal lobe round- 

 ish ; upper ones obovate, toothed or pinnatifid at the base ; silique 4-sided, 

 with the sides somewhat convex, acuminate wath the style. — DC. prodr. I. p. 

 140; Hook. fl. Bor.-Am. 1. ;;. 39. B. arcuata. Bong, in mem. acad. St. 

 Petersb. (6. 'ser.) 2. p. 124. Erysimum Barbarea, Linn. ; C/iam. ^ Schlecht. 

 in Linncea, 1. p. 15. 



/?. gracilis (DC.) : stem slender, nearly simple. 



Along streams and road sides; common in the Northern States ! and appa- 

 rently introduced. Oregon and N. W. America; Sitcha, Bongard. P. Ore- 

 gon, Nnttall. May-June.— One to two feet high, glabrous, branching in a 

 paniculate manner. Flowers in dense racemes.— Mr. Nuttall thinks that the 

 var. 0. is a distinct species, which he calls B. gracilis. 



2. B. pr(eco.v {R. Brown): lower leaves lyrate, the terminal lobe obo- 

 vate ; upper ones pinnatifid, with linear-oblong lobes; siliques linear, elongated, 

 compressed-ancipital; style verv short and thick.— Z?C. prodr. 1. p. 141; 

 Hook. ! fi. Bor.-Am. 1. p. 39. E. precox. Smith. 



Banks of rivers, Canada to lat. 68= !— Stigma nearly as broad as the valve. 

 Siliques 2-3 inches long. — Resembles the preceding, but more slender. The 

 flowers are also smaller, and the siliques longer. 



4. STREPTANTHUS. Nutt. in jour. acad. Philud. 5. p. 134. 



Silique very long, compressed or somewhat quadrangular: style short or 

 none. Seeds in a single series, flat, margined. Sepals erect, colored. Claws 

 of the petals canaliculate, usually twisted Filaments subulate (those of each 



