22 CBUCIFEK^. 



* * Sepals spreading, releasing the claws of the petals. 



2. B. NIGRA (L.), Koch. (BLACK MUSTARD). Not glaucous but dark 

 green, roughish with scattered stiff hairs, stout, 312 ft. high: leaves all 

 petiolate; the lower lyrate, with a very large and lobed terminal lobe; 

 the uppermost lobed or toothed or entire : petals 3 4 lines long, twice 

 the length of the yellowish sepals: pods closely appressed to the rachis of 

 the raceme, 4-angled, %%. in. long, sharply beaked with the long 

 style. Common as the preceding, but taking more exclusive possession 

 of fence corners and rich waste lands. June, July. 



3. B. SINAPISTRUM, Boiss. Annual, 2 5 ft. high, the herbage light 

 green, rough with spreading hairs: lower leaves usually with a large 

 coarsely toothed terminal lobe and smaller ones of angular outline on 

 the rachis: fl. 4 6 lines long: pods 1 \% in. long, ascending, nearly 

 cylindrical, with a stout somewhat 2-edged beak a third as long as the 

 prominently nerved valves, often containing a seed, the seeds under each 

 valve 38. Common by waysides in the vicinity of Berkeley and 

 Oakland; flowering later than B. cainpestris, but earlier than B. nigra. 



14. SISYMBRIUM, Diosc. Erect and rather slender annuals. 

 Leaves not clasping, lyrate-pinnatifid, or (in our species) finely dissected. 

 Flowers small, yellow. Sepals scarcely gibbous at base. Petals unguic- 

 ulate. Anthers mostly linear-oblong, sagittate. Pods linear or oblong- 

 linear, terete or nearly so, obtuse or short pointed; valves slightly 1 3- 

 nerved. Seeds usually numerous, small, oblong and teretish; cotyledons 

 incumbent. 



* Seeds in 2 rows; leaves finely dissected. 



1. S. multifidmn (Pursh), MacM. Simple or with few branches, 

 % 2^ ft. high, canescent with short branching hairs: leaves 1 2-pin- 

 nate, the segments more or less deeply toothed or pinnatifid: petals 1 

 line long or less, about equalling the sepals: pods oblong to linear, or 

 subclavate, % % i n - long* on slender spreading pedicels of equal or 

 greater length, acute at each end, and beaked with a very short style. 

 Plains near Livermore. 



* * Seeds in 1 row; leaves pinnatifid or entire. 



2. S. OFFICINALE (L.), Scop. (HEDGE MUSTARD). Rigid, erect, spar- 

 ingly and divaricately branching above, somewhat hirsute; lowest leaves 

 depressed and rosulate, lyrately and somewhat runcinately pinnatifid, 3 

 6 in. long: pods terete, % i Q l n g tapering from base to summit, nearly 

 sessile, closely appressed to the rachis in a long slender raceme. By 

 waysides and in waste grounds. 



3. S. ACUTANGULUM, DC. Hirsute with scattered simple hairs, 1 2 

 ft. high, with ascending branches: leaves 26 in. long, runcinate-pin- 



