Selenia. CRUCIFERiE. 99 



Tribe 111. BRASSICE.^. DC. 



Silique dehiscent : septum linear. Style often enlarged and with a 

 seminiferous cell at the base. Seeds for the most part globose. Co. 

 tyledons incumbent, conduplicate or longitudinally plicate, with the 

 radical lying in the sinus (0»)* 



19. SINAPIS. Linn.; DC. sysl.2.p.mi. 



Silique somewhat terete ; valves nerved. Style short, acute. Seeds sub- 

 globose, in a single series. Calyx spreading. — Biennial or annual (rarely 

 perennial) herbs. Leaves usually lyratc, incised orpinnatifid. Flowers yel- 

 low, in elongated racemes. — Mustard. 



1. .S. nigra (Linn.): siliques appressed, glabrous, somewhat 4-sided; 

 style short (not rostrate) ; lower leaves lyrate, uppes ones lanceolate, entire. 

 —DC. prodr. \.p. 218 ; Eng. bot. t. 969 ; Darlingt. fl. Cest. p. 390. 



Fields and waste places. June-Aug. Introduced — (f) Lower leaves 

 large, scabrous ; cauline ones glabrous. Sepals yellow. Petals obovate, un- 

 guiculate. Silique about three-fourths of an inch in length, pointed with the 

 short and slender 4-sided style. — Black Mustard. 



2. S. arvensis (Linn.): siliques glabrous, 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; E7ig. bot. t. 1748. 



Western and Northern parts of the State of New York! Lower Canada, 

 Mrs. Percival ! Introduced. June-Aug.— (T) Plant 2-3 feet high. Lower 

 leaves large, somewhat lyrately pinnatifid : upper ones oblong-ovate : all ir- 

 regularly repand-toothed. Flowers bright yellow. Siliques somewhat 

 spreading, \\ inch long ; beak nearly as broad as the silique. Seeds large 

 and black. 



2. SiliculoscB. 



Tribe IV. SELENIEyE. 



Silicle dehiscent : septum broad and membranaceous. Seeds in- 

 verted ! (i. e. with the radicle ascending, and next the placentae.) 

 t Cotyledons plane, accumbent (or nearly so) parallel with the septum. 



20. SELENIA. Nutt, in jour. acad. Philad. 5. p. 132. t. 6. 



Silicle broadly oval, acute at the base, margined ; valves reticulated, some- 

 what inflated : septum sometimes incomplete ; areolae transverse. Seeds 4-6 

 in each cell, orbicular, with a broad and thin cartilaginous border : funiculi 

 free. Radicle very short. Calyx nearly equal at the base, colored, spread- 

 ing. Glands 10. Petals erect. Stamens toothless. Style elongated. — An 

 annual herb. Leaves pinnately parted. Flowers yellow, in leafy racemes. 



S. aicrea (Nutt.! 1. c.) 

 /?. septum nearly wanting. 



