60 CRUCIFER^. Sisymbrium. 



& 2. Aeabidopsis, DC, Silique linear, compressed, somewhat terete : stigma nearly sessile : fioioers 



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



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



Annual : 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 llian the pedicels. — Gay, 

 in ann. sci. nat. 7. p. 399; Hook. jl. Bor.-Am. 1. p. 63; Darlivgt. fl. Cest. p. 388; 

 Torr. ^ Gr.jl. N. Am. 1. p. 93. Arabis Thaliana, Linn.; Eng. bat. 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 the stem smaller, stellately hairy, especially on the upper sur- 

 face. Flowers scarcely two lines long. Petals spatulate-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. 4908. TREACLE mustard. 



[From the Greek, cmo, to cure; on account of its supposed medicijial powers.] 



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

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



^. Erysimastrum, DC. Style short or scarcely any : calyx deciduous : leaves neither cordate nor 



clasping : flowers distinctly pedicellate. 



1. Erysimum cheiranthoides, Linn. WbrtJi-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. 1. p. 198; Hook. fl. Bor.-Am. l.p. 64; 

 Torr. 4" Gr.fl. N. Am. l.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. 



