50 CRUCIFERAE 



earliest days of the American occupation and the Black Mustard spread freely over the moist 

 valley lowlands. Notwithstanding tliat the plant was so cominon in the fifties and sixties, printed 

 botanic^il records, as said, are lackinp. So far as now appears, the binomial Brassica nip^ra, in 

 indication of this species as growing in California, first occurs in Bolandcr's "Catalogue of 

 Plants Growing in tlie Vicinity of San Francisco," published in 1870, page 5. 



Locs. — Hydesville, Humboldt Co., Tracy 4514; Ft. Bragg, W. C. Mathews; Napa, Jepson; 

 Mt. Diablo, Jrpson 9109; Berkeley; Berryessa, Santa Clara Co., Davy 7055; San Luis Obispo, 

 Brewer 484; Mission La Purisima, Jepson 11,931; Santa Barbara; Strawberry Valley, San 

 Jacinto Mts. ; Escondido, C. V. Meyer 21. 



Refs.— Brassica nigra Koch.; Roehl. Dcutschl. Fl. ed. 3, 4:713 (1833) ; Jepson, Fl. W. Mid. 

 Cal. 217 (1901), ed. 2, 184 (1911), Man. 423 (1925). Sinains nigra L. Sp. PI. 6G8 (1753), type 

 north European. 



4. B. incana Meigen. Stem widely branching, II/2 to 3 feet high; herbage 

 hispidnlose, retrorsely so on the stems and petioles; leaf-blades pinnately parted, 

 or the uppermost merely lobed or subentire; flowering racemes subcapitate, mucli 

 elongated in fruit; petals 2 to 3 lines long; pods closely appressed to the axis, 5 to 

 7 lines long, the beak % to I/2 as long as the body, constricted beyond the valves 

 and bearing a single seed in the constricted portion. 



Introduced from Europe; established along the coast and spreading into the 

 interior. May-Sept. 



Immigrant note. — Brassica incana (B. adpressa Boiss.) first appeared in Los Angeles about 

 1909 (Davidson, Bull. S. Cal. Acad. 12:11,-1913). As early as 1895 it is indicated (Syn. Fl. 

 P:134) as collected at San Bernardino by Parish and it was again (1914) noted by Parish in 

 San Bernardino and later (1918) in Redhinds; cf. Bull. S. Cal. Acad. :9*:17 (1920). In the San 

 Francisco Bay region it was first noted in Berkeley about 1915 but probably appeared earlier. 

 It has since spread rapidly throughout this region and has become common: St. Helena, Jepson 

 9831 ; Brannan Isl., lower Sacramento River, Jepson 10,220 ; Oakdale, Jepson 10,569. 



The two long-established grainfield weeds, B. nigra and B. campestris, keep mainly to broken 

 ground, and in great part, complete their cycle during the winter and spring seasons. B. incana, 

 on the contrary, spreads freely over dry unbroken ground and flourishes chiefly during the arid 

 summer season. Of these three the latter is evidently destined to be the more abundant species 

 and is already a serious agricultural pest. 



Refs. — Brassica incana Meigen, Dcutschl. Fl. 3:270 (1842). Sinapis incana L. Cent. PI. 

 1:19 (1755). B. adpressa Boiss. Voy. Espag. 2:38 (1839-45), type loc. Spain; Jepson, Man. 

 423 (1925). Jlirschfeldia incana Lagreze-Fossat, Fl. Tarn et Garonne 19 (1847). 



B. ERUCA L. Sp. PI. 667 (1753), type loc. Switzerland. Garden Rocket. Somewhat succulent, 

 1 to 1% feet high; herbage glabrous or sparingly hirsute; leaf-blades lyrate, pinnately lobed or 

 pinnatifid ; flowers ^/^ to % inch broad, variously colored, the petals strongly veined ; pods erect- 

 appressed, % inch long, the stout flat beak % as long as the body. — Adventive from Europe: 

 fields near Yreka, Butler 1050; newly seeded alfalfa field, San Luis Obispo, Gondii in 1909; 

 vacant lot, San Bernardino, in 1923 (Bull. S. Cal. Acad. 23:129). 



B. ALBA Boiss. Voy. Espag. 2:39 (1839^5). Sinapis alba L. Sp. PI. 668 (1753), type 

 European. White Mustard. Erect annual 1 to 2 feet high, more or less pubescent with stiff 

 Lairs; leaf -blades all pinnatifid with large terminal leaflet or lobe, bluntly toothed; pods on 

 spreading pedicels, bristly, the broad sword-shaped beak equaling or longer than the body ; seeds 

 few, large, pale. — Native of Europe, adventive in orchards or grainfields: Riverside, Bichard 

 Baynor; Santa Monica (Erythca 1:57) ; Surf, Santa Barbara Co., K. Brandegee; Byron, Bio- 

 letti; vicinity of San Francisco (Bolander, Cat. 5, — 1870) ; Vacaville, Jepson 527. 



10. DIPLOTAXIS DC. 



Herbs similar to Brassica. Leaves toothed, pinnatifid, pinnately divided or 

 entire. Petals yellow. Nectar glands 4, minute. Pods linear-elongated, flat or 

 flatfish, short-beaked, borne erect on straight obliquely ascending pedicels; valves 

 mostly 1-nerved; seeds in 2 rows in each cell; cotyledons conduplicate. — Species 

 19, central Europe to north Africa and India. (Greek diploos, double, and taxis, 

 arrangement, referring to the biseriate seeds.) 



1. D. tenuifolia DC. Wall Rocket. Perennial; stems erect, leafy, 1 to 4i/^ 

 feet high; petals 3i/^ to 6 lines long; pods 1 to II/4 inches long. 



Native of Europe, sparingly naturalized in coastal Southern California. Apr. 



