CLASS XV. ORDER I. 265 



once. Calyx nearly sessile, with five short, rounded segments, 

 calyculated with three similar scales at base. Corolla large, 

 white, inflated, contracted at the mouth, not unlike the head of 

 a serpent; the lower lip in three small segments, with two 

 woolly stripes within. Filaments hairy below. Anthers en- 

 tangled together by a woolly covering. A short, smooth rudi- 

 ment of a fifth filament is found between the two upper stamens. 

 Style long, slender, curving downward. — Roxbury, Cambridge. — 

 August, September. — Perennial. 



Class XV. TETRADYNAMIA. Six stamens, four 

 long and two sliort. 



Order I. SILICULOSA. Seeds in a silicle. 



284. Draba. Silicle entire, oval-oblong, the vah^es 

 flat, parallel to the dissepiment. 



285. Lepidium. Silicle elliptic, emarginate, the 

 valves carinate, but not margined. 



286. Thlapsi. Silicle inversely heart shaped, the 

 valves carinate and margined. 



287. BuNiAS. Silicle deciduous without opening, 

 somewhat four sided, two of its angles more acute. 



288. CocHLEARiA. Siliclc turgid, wrinkled, many 

 seeded, valves gibbous, obtuse. 



289. Cameltxa. Silicle obovate or subglobose, 

 valves swelling, opening with a part of the style, cells 

 many seeded, seeds oblong, not bordered ; style fili- 

 form. 



Order \l. SILIQUOSA. Seeds in a silique. 



290. Arabis. Silique compressed. Four nectarife- 

 rous glands like scales, reflected between the leaves 

 of the calyx. 



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