00 CRUCIFERiE. Sisymbrium. 



^ 2. Aradidopsis, DC. Silique linear, compressed, somewhat terete : stigma nearly sessile : flowers 

 white (or rose-color) : peduncles usually short. 



2. Sysymbrium Thaliana, Gay. Wall Cress. Mouse-ear Cress. 



Annnal : stems often many from one root, rather naked, branching above, erect ; leaves 

 (and lower part of the stem) hairy, sparingly toothed ; radical ones ovate-oblong or spatulate- 

 oblong, somewhat petioled ; siliques erect-spreading, rather longer than the pedicels. — Gay, 

 in ami. sci. nat. 7. p. 399; Hool. fl. Bor.-Am. 1. p. 63; Darlingt. fl. Cest. p. 388; 

 Torr. 4- Gr.fl. N. Am. 1. p. 93. Arabis Thaliana, Linn.; Eng. hot. t. 901 ; Pursh, fl. 2. 

 p. 437 ; DC, prodr. 1. p. 144. A. parviflora, Raf. in Amer. month, mag. \. p. 43. 



Stem 6-15 inches high, slender, terete. Leaves mostly radical in a circular cluster, 

 scarcely an inch long ; those of tlie stem smaller, stellately hairj', especially on the upper sur- 

 face. Fl )W ers scarcely two lines long. Petals spatulatc-oblong, more than twice the length 

 of the calyx. Pedicels of the fruit filiform, 4-5 lines long, spreading. Siliques 6-8 lines 

 long, moderately compressed, with about 20 oval seeds in each cell, arranged in a single 

 series. 



In sandy fields on rocks. May. Apparently native, and identical with the European species. 



8. ERYSIMUM. Linn.; Endl. gen. A90S. treacle MUSTARD. 



[From the Greek, enu>, to cure; on account of its supposed medicinal powers.] 



Silique 4-sided. Calyx closed. Seeds not margined : cotyledons oblong, plane. — Herbs, 

 mostly biennial, of various habit. Flowers yellow or rarely white. 



§. Erysimastrtm, DC. Style short er scarcely any : calyx decidumis : leaves neither cordate nor 

 clasping: flowers distinctly pedicellate. 



1. Erysimum cheiranthoides, Linn. Worm-seed Treacle Mustard. 



Somewhat scabrous with a minute oppressed pubescence ; leaves lanceolate, denticulate or 

 entire ; siliques erect, nearly twice the length of the spreading pedicels ; stigma small, entire, 

 nearly sessile. — Pursh, fl. 2. p. 436; DC. prodr. I. p. 198; Hook. fl. Bor.-Am. I. p. 64; 

 Torr. ^ Gr.fl. N. A?n. I. p. 94. E. parviflorum, Pers. syn. 2. p. 199 ; Nutt. gen. 2. p' 16. 



Root biennial, fusiform. Stem 1 - 2J feet high, sparingly branched. Pubescence 3-4- 

 parted. Leaves 1-2 inches long and 4-6 lines wide. Flowers small, yellow. Siliques 

 about an inch long, pointed with a very short style. 



Along streams in the western part of the State. July - September. A native also of 

 Europe. 



