214 CRUCIFERAE (MUSTARD FAMILY) 



t, oval or ( 



to Utah and Nevada. 



purplish: silique permanently finely pubescent, oval or orbicular, the sinus 

 narrow and shallow. From Yellowstone Park t< 



8. THLASPI L. WILD CANDYTUFT 



Annual or perennial herbs, with entire leaves, the radical rosulate (entire 

 or toothed), the cauline auric ulate-clasping. Stems usually simple, termi- 

 nating in a more or less elongate raceme. Sepals short, equal at base. Petals 

 obovate or oblanceolate, entire. Style slender, or rarely none. Silique or- 

 bicular, elliptic-oblong or oblanceolate; the valves very strongly and usually 

 sharply keeled, often winged, especially toward the apex. 



Capsules orbicular, large 1. T. arvense. 



Capsules obovate or oblong-cuneate. 



Basal leaves closely rosulate, thick, dark or purplish-green. 



Oval or orbicular, abruptly contracted to the petiole . . . 2. T. Fendleri. 

 Broadly spatulate . . . . . . . . . 3. T. coloradense. 



Basal leaves openly rosulate, thin, pale green. 



Petals 5-6 mm. long; style 1.5 mm. long 4. T. glaucum. 



Petals 2-3 mm. long; style 0.5 mm. long . . . . . 5. T. parviflorum. 



1. Thlaspi arvense L. Sp. PI. 646. 1753. Glabrous annual, 2-3 dm. high: 

 stems simple or branched above: leaves spatulate below, oblong upwards, 

 obtuse, remotely and irregularly dentate: flowers small, the greenish sepals 

 somewhat exceeded by the white 3 mm. long petals: silique very flat, or- 

 bicular, broadly winged, deeply notched at apex. Adventive and occurring 

 as a weed in waste ground, increasingly so in our range; often called FEENCH 

 WEED. 



2. Thlaspi Fendleri Gray, PI. Wright. 2: 14. 1853. Glabrous perennial, 

 8-15 cm. high: branches of caudex several, short, slender, covered with the 

 somewhat rosulate leaves: basal leaves small, oval or orbicular, mostly less 

 than 1 cm. long, abruptly contracted to the short slender petiole; stem leaves 

 auriculate-clasping, ovate or oblong, acute or obtuse, 5-15 mm. long: petals 

 spatulate, 5 mm. long: sepals elliptic, with petaloid margin and a purplish 

 spot, half as long as the petals: silique obovate-cuneate, truncate or slightly 

 depressed at summit, 6-7 mm. long; the slender style nearly one half as long. 

 Subalpine, flowering in summer; southern Colorado and New Mexico. 



3. Thlaspi coloradense Rydb. Bull. Torr. Bot. Club 28: 280. 1901. Quite 

 similar; the caudex denser and the stems as well as the leaves inclined to be 

 rosulate-spreading: the early leaves murky green or purplish; the basal broadly 

 spatulate; otherwise like the preceding. T. alpestre. (T.purpurascensHydb. 

 1. c., at least as to Colorado specimens.) One of the earliest flowers at middle 

 elevations; Wyoming and Colorado. 



4. Thlaspi glaucum A. Nels. Bull. Torr. Bot. Club 25: 275. 1898. Gla- 

 brous and glaucous, 1-3 dm. high: caudex open and slender-branched: stems 

 few, erect: leaves all large, thin and pale or glaucous; the basal oblong or ob- 

 ovate, obscurely repand-denticulate, petioled; the cauline elliptic or deltoid- 

 ovate: petals spatulate. 6 mm. long, much exceeding the thin greenish sepals: 

 silique obovate, obtuse or emarginate, twice as long as the style but exceeded 

 by the divaricate pedicels. Late summer in the highest mountains; Colorado 

 to Idaho. 



5. Thlaspi parviflorum A. Nels. Bull. Torr. Bot. Club 27: 264. 1900. 

 Similar but smaller in every way, less glaucous: the floral parts half as large: 

 silique spatulate, with a thick style only 0.5 mm. in length. (T. Nuttallii Rydb. 

 1. c. 29: 235.) Open slopes, middle elevations; Yellowstone Park. 



9. BRASSICA L. MUSTARD 



Coarse annual, biennial, or perennial herbs with rather large more or less 

 pinnatifid leaves and large yellow 1 flowers in elongated racemes. Siliques 

 elongated, subterete, beaked with an indehiscent prolongation of the convex 



