214 CRUCIFERAE (MUSTARD FAMILY) 



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

 narrow and shallow. — From Yellowstone Park to Utah and Nevada. 



8. THLASPI L. Wild Candytuft 



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

 or toothed), the cauline auriculate-clasping. "Stems iisually 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 rosiilate, thick, dark or purplish-green. 



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

 Broadly spatulate . . . . . '. . . . 3. T. coloradfen^e. 



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 Fbbnch 

 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 eUiptic, with petaloid margin and a purplish 

 spot, half as long as the petals: silique Qbovate-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 . purpurascensB,ydb. 

 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 elUptio 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. NuttaUii Rydb. 

 I.e. 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 flowers in elongated racemes. Siliques 

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



