328 BRASSICACEAE 



29. L. dictyotum A, Gray. Annual; stems branched at the base, spread- 

 ing, 3-10 cm. long, hirsute; basal leaves either linear, entire, or pinjnatifid with 

 distant linear lobes; stem-leaves narrowly Unear; petals none or rudimentary; 

 stamens 4; pod ovate, wing-margined, with prominent acute lobes, hirsute, 3 

 mm. long. Sandy places: Wash. — Ida.— Utah— Calif. Son. Mr-Je, 



4. THLASPI (Tourn.) L. Penny Cress, Penny-grass. Wild Sweet 



Alyssum. 



Glabrous annuals or perennials, with undivided and often clasping leaves. 

 Flowers racemose, perfect. Sepals equal. Petals white, or rarely pink or 

 purplish, obovate or oblanceolate. Stamens free, unappendaged; anthers short, 

 ovaL Styles slender or none; stigma small, entire. Capsules orbicular, oblong 

 or cuneate; valves strongly keeled, often winged, especially towards the apex. 

 Seeds 2-8 in each cell. 



Pods orbicular in outline, broadly wing-margined and deeply notched at the apex; sepals 



green; annuals. .1- ^- Q-^^ense. 



Pods obovate or oblanceolate-cuneate in outline, with narrow margins, acute, truncate 



or slightly notched at the apex; sepals with white or rarely piu-phsh margins; 



"DGFG nn i s^ Is 

 Petafe 2.5-a nim. long; pod oblanceolate-cuneate, 2-2.5 mm. ^\ide- 2. T. parviflorum. 

 Petals 4-7 mm. long; pods cuneate or obovate-cuneate, 3 mm. or more wide. 



Pods acutish at the apex, neither emarginate nor retuse. 3. T. cahformcmn. 



Pods rounded or truncate at the apex, emarginate or retuse. 



Pods rounded at the apex; sinus narrow. x = «^ 



Caudex rather slender; stem 1-2 dm. high; petals spatulate. about 5 mm. 



long 4. T. Nuttalln. 



Caudex stout, densely cespitose; stem less than 1 dm. high; petals broadly 

 obovate. 6-7 mm. long. 5. T. color adense . 



Pods truncate or nearly so at the apex; sinus very broad and open. 



Stem 2-3 dm. high; stem-leaves ample, broader than the basal ones; sepais 



green, with white margins. 6. T. glaucum. 



Stem 1 dm. or less; stem-leaves reduced; sepals ^and often also petais 

 purplish. 7. r. vurpurascens, 



1. T. arvense L. Annual, glabrous; stem 1.5-4.5 dm. high; basal leaws 

 early deciduous, petioled; blades oblanceolate; stem-leaves oblong or elliptic, 

 dentate, the upper auricled and clasping at the base; petals about 4 mm. long, 

 oblanceolate or spatulate; pod 12-18 mm. long, 10-15 mm. broad. Waste places 

 and roadsides: Lab.— Fla.— Colo.— Utah— B.C.; adv. or nat. from Eu. Plain 



■Submont, My-Jl. 



2, T. parviflorum A. Nels, Stems few, 1-3 dm. high; lower leaves rosulate 

 at the base, glabrous, 5-20 mm. long, short-pctioled, eUiptic or oval; stem-leaves 

 5-12 mm, long, oblong, sagittate and clasping at the base; petals oblanc^olat^ 

 pod 5-7 mm, long, scarcely winged, slightly emarginate. Open valleys: Wyo. 

 Mont. Suhmont, — MonL Je. 



3- T. californicum S. Wats. Stems 1-2 dm. high, simple; basal leaves 

 petioled, 1-3 cm. long, oval or spatulate; stem-leaves oval, 5-10 mm. long, sagit- 

 tate and clasping at the base; petals spatulate, 4-5 mm. long; pod cuneate, 5 / 

 mm. long. IMoxmtain valleys: Mont.— Utah— Calif.— Wash. SubmonL—buO- 

 alp, Je-Au. 



4. T. Nuttallii Rydb. Stems sohtary or few, 1-2 dm. high, leafy; basal 

 leaves petioled, 1-2 cm. long, glabrous, oval, spatulate, or obovate; stem-leaves 

 rounded-oval, about 1 cm. long, cordate and clasping at the base; pod cuneate- 

 obcordate, about 7 nam. long. Valleys and hillsides: Mont. — Colo. VVasn. 

 SubmonL — Mont, My-Jl. 



5. T. coloradense Rydb. Stems 2-8 cm. long; basal leaves broadly spatu- 

 ate, 1-2 cm. long, fleshy, sinuately crenate or subentire; stem-leaves oblong or 

 obovate, 3-10 mm. long, obtuse; pod obovate, about 6 mm. long; wing-margms 

 Yery narrow. Alpine peaks: Colo. — Utah. Alp. — Mont, Jl-Au. 



6. T. glaucum A. Nels. Stems leafy, 1-3 dm. high; basal leaves peti- 

 oled, 2-3 cm. long, oval or obovate, glabrous and glaucous, entire or repana, 

 stem-leaves ovate-oblong, cordate and clasping at the base; petals about b mm^ 

 long; pod cxmeate, wing-margined above. Valleys: Mont. — Colo. Utah, ou - 

 mont, — Subalp. Je-Jl. 



