TETRADYNAMIA.— SILICULOSA. 2^7 



ed, smooth ; silicle suborbicular, loDger than the 

 pedicel ; its wings dilated longitudinally. 

 HAB. Fields. June. 0. Stem erect, 8 — 12 in. 

 high ; leav. smooth ; fi. wh. 



2. T. tuberosum : leaves rhombic-ovate, obsolete!} 



dentate, smooth, sessile ; radicle ones on long pe- 

 tioles ; stem pubescent ; root tuberous ; silicle 

 orbicular. 

 HAB. Pennsylvania. April — May. Stem 4 — 5 iff* 

 high ; fi. rather large, rosaceous. 



3. T. Bursa-pastoris : silicle triangular-obcordate, with- 



out wings ; cells many-seeded ; radicle leaves pin- 

 natifid. 

 HAB. Pastures, &c. March— Oct. ©. Stem 6— 

 12 in. high; fi. small, corymb., wh. §. 



412. DRABA. Whitlow-grass. Crucifera\ 



*. Petals entire. 



1. D. arabisans : stem leafy, somewhat branched, sub 

 pubescent ; leaves lanceolate, acutely dentate ; 

 silicle linear, smooth, longer than the pedicel. 

 HAB. Rocks. $. Silicle elongated, acuminate, 

 contorted. 



**. Petals bifid. 



J, D. rerna : scapes naked ; leaves lanceolate, subin 

 cised, hairy ; silicle elliptical-oblong. 



HAB. Fields and hills. March — May. ©, leav. 

 all rad. ; scape 2 — 6 in. long ; fi. wh. 

 '. D. caroliniana : stem leafy at the base, hispid, na- 

 ked and smooth at the apex ; leaves ovate-round 

 ish, hispid, entire, hispid ; silicle linear, smooth, 

 longer than the pedicels. 



HAB. Fields. April. 0. Stem 1—2 in. high; 

 silicle 4 — o in. long ; fi. wh. 



. ALYSSUM. Gold-of-PIeasure. Crucifcra. 



\ ! dnitatum : stem erect and herbaceous ; ra< i 

 paniculate ; radical leaves subruncioately denl 

 -omewhat scabrous; cauline linear-lanceolate, 



