SiNAPis. CRUCIFERiE. 61 



Tribe III. BRASSICEJE. DC. 



Silique dehiscent: septum linear. Style often enlarged, loith a seminiferous cell at the 

 base. Seeds for the most part globose. Cotyledons incumbent, conduplicate or longi- 

 tudinally plicate, with the radicle lying in the sinus (0»). 



9. SINAPIS. Tourn. ; Endl. gen. 4950. MUSTARD. 



[Name from the Greek, sinapi, which again is said by De Theis to be derived from the Celtic nap, a turnip or cabbage.] 



Silique somewhat terete ; valves nerved. Style short, acute. Seeds somewhat globose, in a 

 single series. Calyx spreading. — Biennial or annual (rarely perennial) herbs. Leaves 

 usually lyrate, incised or pinnatifid. Flowers yellow, in elongated racemes. 



1. SiNAPis NIGRA, Linn. Black Mustard. 



Siliques appressed to the peduncle, glabrous, somewhat 4-comered ; style short (not ros- 

 trate): lower leaves lyrate ; upper ones lanceolate, entire. — DC. prodr. 1. p. 218 ; Bigel.Jt. 

 Bost. p. 254 ; Beck, bot. mid. and north. States, p. 33 ; Torr. compend. p. 252 ; Eng. bot. 

 t. 969 ; Darlingt.fl. Cestr.p. 390 ; Torr. ^ Gr.f.. N. Am. I. p. 99. 



Annual. Stem 3-6 feet high, smooth, with numerous spreading branches. Lower leaves 

 large, scabrous ; cauline ones smooth. Calyx yellow. Siliques about three-fourths of an 

 inch long, slightly torulose, pointed with the short and slender 4-sided style. Seeds dark 

 brown, very acrid. 



Fields and waste places. June - August. Naturalized in many parts of the State. The 

 seeds afford mustard, so well known as a stimulating condiment. 



2. SiNAPis ARVENSis, Linn. Wild Mustard. Charlock. 



Siliques smooth, many-angled, torose, about three times the length of the slender somewhat 

 ancipital style; stem and leaves more or less hairy. — DC. prodr. 1. p. 219; Eng. bot. 

 t. 1748; Torr. <^ Gr.fl. N. Am. 1. p. 99. 



Annual. Plant 2-3 feet high, somewhat diffusely branched, sparsely hispid with short 

 retrose stiff hairs. Lower leaves 6 inches or more in length, lyrately pinnatifid ; upper ones 

 oblong-ovate, repandly toothed. Flowers as large as in the common turnip, bright yellow. 

 Pedicels of the fruit 2-3 lines long, thick and rigid. Siliques about an inch and a quarter 

 in length, pointed with the long stout style, strongly nerved ; septum zigzag, from the large 

 round seeds pressing it alternately into the two cells. 



Common in wet meadows and fields in the western part of the State : a noxious weed, in- 

 ^oduced from Europe. June - August. 



