40 CRUCIFEE^E. Brassica. 



3. B. Sin apis trum, Boiss. Annual, rough with spreading hairs, 2 to 5 feet 

 high : lower leaves usually with a large coarsely toothed terminal lobe and a few 

 smaller ones upon the rhachis ; the upper leaves often undivided, oblong or lanceo- 

 late : pods somewhat tomlose, 1 to 1^ inches long, more than a third occupied by 

 the stout 2-edged beak ; valves often ribbed by the prominent nerves. Sinapis 

 arvensis, Linn. 



The Charlock of the Eastern States and Europe, where it is often a troublesome weed in grain- 

 fields. Sparingly naturalized in Southern California. 



14. BARBAREA, R. Brown. WINTER CRESS. 



Pod linear, somewhat flattened, pointed; valves somewhat carinate. Seeds in 

 one row, oblong, turgid, marginless ; cotyledons slightly oblique. Petals yellow. 

 Glabrous erect branching biennials or perennials, with angled stems and entire or 

 pinnatilid leaves. 



A small genus of temperate regions, some of the species widely distributed. The only one 

 native to America is the following. 



1. B. vulgaris, R Br. Perennial, 1 to 3 feet high : lower leaves lyrate-pin- 

 natifid (the radical pinnate), with a large rounded terminal lobe and 1 to 5 pairs of 

 lateral ones, oblong in the cauline leaves ; upper leaves obovate, more or less pin- 

 natifid at base : flowers 2 to 3 lines long : anthers short, oblong : pods erect, often 

 appressed, 1 to 1^ inches long, somewhat angled when mature, about 25-seeded, 

 beaked with the rather slender style. Gray, Gen. 111. i. 148, t. 62. 



Var. arcuata, Koch. Pods and pedicels spreading. 



Inhabiting marshes and damp places. Only the variety seems to have been collected in Cali- 

 fornia, near San Francisco and northward to Sitka, though the typical form is common in Oregon 

 and eastward ; the species ranges nearly round the world. 



15. SISYMBRIUM, Linn. HEDGE MUSTARD. 



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

 nerved. Seeds \isually in one row, small, oblong and teretish, not margined ; coty- 

 ledons incumbent. Sepals scarcely gibbous at base. Petals yellow or yellowish. 

 Anthers mostly linear-oblong, sagittate. Erect herbs, with small flowers, the 

 leaves (in our species) not clasping or auriculate at base, rarely entire, often finely 

 dissected. 



A large genus of rather difficult definition, principally confined to the northern temperate zone. 

 The American species, less than a dozen, belong to the region west of the Mississippi, S. canes- 

 cens alone ranging farther eastward. 



* Seeds in two rows : leaves usually finely dissected. 



1 . S. canescens, Nutt. Annual, canescent with short branching hairs : stems 

 branched, | to 2| feet high : leaves 1 - 2-pinnate, the segments more or less deeply 

 pinnatifid "or toothed : petals light yellow, equalling the sepals, usually a line 

 long or less : pods oblong to linear, 3 to 6 lines long, a line broad or less, acute 

 at each end and beaked with the very short style, shorter than the slender spread- 

 ing pedicels : seeds ovate-oblong, a third of a line long.- Gray, Gen. 111. i. 152, 

 t. 64 ; Fournier, Sisymb. 65 ; Watson, Bot. King Exp. 23. 



the 



from the .- , __ 



brachycarpinn cited by Fournier as from San Diego is probably but a form of this, as is certainly 

 the northern plant so named by Richardson. The species is <|iiite variable, especially in the 

 section of the leaves and length of the pod. 



