26 DICOTYLEDONOUS PLANTS. 



rounded by a membranous wing. Calyx equal at base. Petals 

 entire. Stamens somewhat toothed. 



Tetradynamia. Siliculosa. 



A ? dcntatum Nutt. : stem erect and herbaceous ; radical leaves 

 subruncinately toothed and somewhat scabrous ; cauline ones linear- 

 lanceolate, sessile, nearly smooth ; racemes paniculate ; pouch ellip- 

 tical, compressed, pubescent, contorted, terminating in a style near its 

 own length, shorter than the pedicel. Draba arabisane Pursh, not of 

 Mich. (Nutt.). 



HAB. Rocks. N. S. ? May. H.Stem 6 inches high. This 

 plant is probably not a native of the northern section of the U. S. 



5. DRABA. Linn. 



Pouch sessile, oval or oblong ; valves flat or convex. Seeds 

 many, not margined. Calyx equal. Petals entire. Stamens 

 without tuetli. Tetradynamia. Siliculosa. 



1. D. carnliiiifinti ll r (ilf. : stem leafy at the base, hispid, naked and 

 smooth at the top ; leaves ovate-roundish, entire, hispid ; pouch lin- 

 ear, smooth, longer than the pedicels. D. hispidula Mick. 



HAB. Fields. Perm, to Geor. W. to Mies. April. .Stew 

 2 4 inches high. Leaves clustered on the lower part of the 

 stem, very hairy. Poucli 1-2 an inch long, linear-lanceolate. 

 Flowers white. 



2. D. arabizans Mich. : stem leafy, somewhat branched, subpubes- 

 cent ; leaves lanceolate, acute, toothed ; pouch linear, smooth, longer 

 than the pedicel. 



HAB. Rocks. Can. to Virg. W. to Miss. May, June. 0". 

 Pouch 5 6 lines long, erect, acuminate, twisted. Flowers white. 



6. EROPHILA. De Cand. 



Pouch oval or oblong ; valves flat. Seeds many, not mar- 

 gined. Calyx equal. Petals 2-parted. Stamens without teeth. 



Tetradynamia. Siliculosa . 



E. vulgaris De Cand. : pouch elliptic, shorter than the pedicel ; scape 

 5 15 flowered. E. americana De Cand. ? D. vema Pursh. Nutt. 



HAB. Fields. Can. to Virg. March May. Q. Scape 26 

 inches high. Leaves lanceolate, subincised, hairy. Flowers 

 white. Specimens of this plant obtained from my friend, Dr. 

 Matthew Stevenson, of Washington co. N. Y. agree in all re- 

 spects with the foreign E. rulgaris, as do also those which 

 I have collected elsewhere. Whether E. americana of De Can- 

 dolle is a mere variety of this, I have no means of determining ; 

 but I think there can be no doubt that Draba caroliniana (D. hit- 

 pidula Mich.) is entirely distinct from the present plant. 



Whitlow Grass. 



