BRASSIACEAE. 
153 
Pods emarginate; sinus narrow. 
Rootstock rather slender; stem 1-2 dm. high ; petals spatulate, about 5 mm. 
long. 2. T. Nuttallii. . 
Rootstock stout, densely caespitose; stems less than 1 dm. high; petals broadly 
obovate, 6-7 mm. long. 3. T. coloradense. 
Pods truncate or nearly so at the apex ; sinus broad and open. 
Stem 2-3 dm. high; stem-leaves ample, broader than the basal ones; sepals 
green. 4. T. glaucum. 
Stems 1 dm. high or less ; stem-leaves reduced ; sepals and often also petals 
purplish. 5. T. purpurascens. 
1. Thlaspi arvense L. In waste places from Lab. to B. G, N. Y. and Colo. 
Introduced from Europe.—Alt. 5000-10,000 ft.—Quimby; Silverton; plains 
and foot-hills near Boulder; Pass Creek. 
2. Thlaspi Nuttallii Rydb. ( 7 \ cochleariforme Nutt.; not DC.) Among 
rocks in the mountains from Mont, to Wash, and Colo.—Alt. 8000-12,000 ft.— 
Dead Lake; Minturn, Eagle Co.; Bob Creek; banks of Michigan Creek, near 
Teller; North Park. 
3. Thlaspi coloradense Rydb. In wet places, among rocks, on the peaks, in 
Colo.—Alt. 6000-14,400 ft.—Foot-hills, Larimer Co.; Gray’s Peak; along 
Beaver Creek; above timber line, west of Cameron Pass; Sierra Blanca; sum¬ 
mit of Pike’s Peak; Grand Mesa; west slope of Bald Mountain; Clear Creek; 
Red Mountain, south of Ouray; Seven Lakes; Los Pinos; Tennessee Pass; 
Cheyenne Mountain; West Spanish Peak; South Cheyenne Canon; Massif de 
l’Arapahoe; Spicer, Larimer Co. 
4. Thlaspi glaucum A. Nels. In mountain valleys and canons from Ida. to 
Colo, and Utah.—Alt. 8000-13,000 ft.—Spring Canon; Red Mountain; Pike’s 
Peak Valley; Silver Plume; Gray’s Peak; Bob Creek; Cameron Pass; Pass 
Creek; near Ironton, San Juan Co.; Rabbit-Ears, Larimer Co. 
5. Thlaspi purpurascens Rydb. Among rocks, on the peaks of Colo, and 
Ariz.—Alt. 7000-14,300 ft.—Gray’s Peak; Cimarron; Spring Canon; Horse- 
tooth Gulch; gulch west of Dixon Canon; Rist Canon; Table Rock; Front 
Range, Larimer Co.; Dixon Canon; headwaters of Sangre de Cristo Creek; 
Iron Mountain; Eldora to Baltimore. 
4. BURSA Weber. Shepherd’s Purse. 
1. Bursa Bursa-pastoris (L.) Britton. In waste places and fields from Lab. 
to Wash, and Calif.—Alt. 4000-9000 ft.—Quimby; Table Rock; Ft. Collins; 
hills about Box Canon, west of Ouray; Sangre de Cristo Creek; Mancos. 
5. SMELOW SKIA. 
Segments of basal leaves spatulate. 1. S. americana. 
Segments of the basal leaves linear or linear-oblong. 2. 5 *. lineariloba. 
1. Smelowskia americana Rydb. (S. calycina B. & H.; not C. A. Mey.) 
On the higher mountain tops from Mont, to Colo, and Nev.—Alt. 10,coo- 
12,000 ft.—Cumberland Basin, La Plata Mountains; Devil’s Causeway; moun¬ 
tain northwest of Como; Ragged Mountain, Gunnison Co.; Mt. Abram, 
Ouray. 
2. Smelowskia lineariloba Rydb. On alpine peaks of Colo.—Alt. 12,coo- 
14,000 ft.—Douglass Mountain; Georgetown; Silver Plume; northwest of 
Como; near Ironton, San Juan Co.; Mt. Bartlett, Robinson. 
