80 



CRUCIFERAE 



sliort, oval. Pod obcom pressed, in ours cuneate, obovate or orbicular, the valves 

 often win«,'ed, especially towards the apex. Seeds 2 or several in each cell; cotyle- 

 dons accnmbent. — Species about 60, North America, Europe, Africa, Asia. (Greek 

 thlan, to crush, on account of the strongly llattened pods.) 



Perennial; pod obovate; seed smooth 1- ^- alpestrc. 



Annual; pod orbicular; seed rugose 2. T.arvense. 



1. T. alpestre L. Mountain Penny Cress. Stems commonly many from a 

 branchinjr perennial crown, 3 to 8 inches high; leaves mostly in a basal tuft, the 

 blades of these round-obovate to oblanceolate, 3 to 6 lines long, narrowed to slender 

 petioles 1 to 2 times as long, the blades of the cauline ovate to oblong, sessile- 

 aiiriculate; raceme ratlier dense; liowers white, 2 to 3 lines long; petals rather 

 spreading, twice the length of the sepals ; pods narrowly obovate or cuneate, 3 to 

 4 lines long, twice as long as wide, retuse or truncate at apex, flattened toward the 

 margin, the summit narrowly winged; style slender, 1/2 to nearly 1 line long. 



Northern mountains, 5000 to 7000 feet : Humboldt, Trinity and Siskiyou Cos., 

 east to Plumas Co. North to British Columbia; New Mexico to Montana. Europe, 

 Asia. Apr.-May. 



Locs. — Spanish Peak; Forest House Mt., Siskiyou Co., Butler 119; Marble Mt., Jepson 

 2842; Dorleska, Trinity Co. The usual form passes into the var. calif omicum Jepson, Four to 

 12 inches high; raceme looser; pods truncate to retuse at apex. — Humboldt Co.: Hupa, Chandler 

 1377; Supply Creek, Davy ^ Blasdale 5736; Kneeland Prairie, Tracy 4043. 



Refs. — Thlaspi alpestre L. Sp. PI. ed. 2, 2:903 (1763), type European; Jepson, Man. 437, 

 fig. 423a (1925). Var. californicum Jepson, Man. 437, fig. 423b-d (1925). T. calif oi-nicum, 



Wats. Proc. Am. Acad. 17:365 (1882), type loc. Knee- 

 land Prairie, Humboldt Co., Rattan. T. glaucum Nels. 

 Bull. Torr. Club 25:275 (1898), type loe. Battle Lake, 

 Wyo., Nelson 4176. T. alpestre var. glaucum Nels. 

 First Report on Fl. Wyo. 84 (1896). T. glaiimm var. 

 hesperium Payson, Univ. Wyo. Publ. Sci. Bot. 1:154 

 (1926), type loc. Dorleska, Trinity Co., Hall 8570. 



2. T. arvense L. Field Penny Cress. 

 (Fig. 141.) Annual, erect, 8 to 14 inches 

 high, often branched above; leaves i/^ to 2 

 inches long, rather remotely toothed, the 

 blades of the basal spatulate, those of the cau- 

 line oblong, obtuse; flowers smaller than in 

 T. alpestre and with narrower petals; pods 

 orbicular or nearly so, i/^ inch in diameter, 

 strongly obcompressed, broadly winged, the 

 apex deeply notched ; style very short. 



Introduced from Europe, adventive in 

 Modoc Co. and Los Angeles Co. Also called 

 French Weed. 



Locs. — Adin, J. L. Chace; Alturas, L. S. Smith 

 1092; Henniger Flats, San Gabriel Mts., Peirson 66, 

 in 1918. 



Fig. 141. Thlaspi ARVENSE L. a, base Refs. — Thlaspi arvense L. Sp. PI. 646 (1753), 



of plant, XVs;b, upper part of plant, type European; Britt. & Br. 111. Fl. 2:114, fig. 1692 

 X Va; c, infl., X Vs ; d, pod, X 1%. (1897) ; Jepson, Man. 437 (1925). 



25. CORONOPUS Ludwig 



Prostrate annuals (exhaling a lieavy-scented odor), with pinnatifid leaves and 

 short racemes of minute greenish-white floAvers. Sepals oval, spreading. Stamens 

 6, or often only 4 or 2. Pod small, more or less didymous, flattened contrary to 



