MUSTARD FAMILY 325 



Plants branched near the base; petals usually present (except in L. diver- 

 Racemes usually numerous, on short branches from the axils of the upper 



leavas; pods broadest below the middle; wing-margins narrow 

 Axillary racemes very short and dense, usually shorter than the 

 leaves; petals more than half as long as the sepals. 



21. L. ramosissimum. 

 Axillary racemes at last elongate; petals very minute or lacking. 



22. L. divergens. 



Racemes elongate, terminal; pods broadest above the middle- wing- 

 margins fully 0.5 mm. wide at the apex. 23. L. elongalum. 



Plant simple below, branched above; petals none; racemes elongate 



terminal. 24. L. densiflorum. 



Pods hirsute, at least on the margins. 



Stem-leaves linear, mostly entire. 25. L. pubecarpum. 



Stem-leaves spatulate, toothed or laciniate. 26 L Georginum 



Wing-margins of the fruit produced at the apex into acute lobes or teeth. 



Stem erect, 3-5 dm. high. 27. L. Fletcheri. 



Stem decumbent, 3-15 cm. high. 



Pod obovate or elliptic; stamens 2; leaves linear or linear-spatulate. 



28. L. Bourgeauanum. 

 Pod ovate; stamens 4; basal leaves often pinnatifld. 29. L. dictyotum. 



1. L. perfoliatum L. Annual or biennial; stems suberect, 2-4 dm. high, 

 more or less pilose; lower leaves bipinnatifid into linear divisions; upper stem- 

 leaves entire, cordate or reniform, clasping, glabrous; petals yellow, fully 1 mm. 

 long; stamens 6; pod 4 mm. long, orbicular, broadly ovate, or rhombic-elliptic, 

 slightly emarginate; style about equalling the width of the wings. Waste places: 

 Utah; nat. from Eu. My-Je. 



2. L. sativum L. Glabrous, bright green annual; stem 3-5 dm. high, 

 branched; lower leaves twice pinnate, 5-20 cm. long, with obovate or oblanceo- 

 late, toothed divisions; petals spatulate, white or pinkish, 2 mm. long; stamens 

 6; pod obovate, 5 mm. long, glabrous, strongly winged above, emarginate; wing 

 partly adnate to the style. Waste places: Que. N.Y. Mont. B.C.; escaped 

 from gardens, native of Eu. Plain Submont. My-Au. 



3. L. integrifolium Nutt. Stems few, 2-5 dm. high, simple below, gla- 

 brous; leaves entire, fleshy; petals 2.5 mm. long, obovate; pod 4-5 mm. long, 

 elliptic; style scarcely 1 mm. long. L. utahense Jones. L. Zionis A. Nels. 

 Plains: Wyo. s Wash. Ariz. Son. Je. 



4. L. Vaseyanum Thellung. Fruticose at the base; stems 2-4 dm. high, 

 glabrous; lower leaves cuneate, 2-10 cm. long, the upper oblanceolate, entire, 

 glabrous; petals clawed, 2 mm. long; pod ovate, 3-3.5 mm. long; style about 0.5 

 mm. long. L. spathulatum Vasey, not Phil. Mountains and hills: Colo. w 

 Tex. N.M. Son. Je-S. 



5. L. crenatum (Greene) Rydb. Stem 5-9 dm. high, glabrous, simple; basal 

 leaves 5-15 cm. long, petioled; upper stem-leaves sessile and more entire; petals 

 short-clawed, 3 mm. long; pods ovate, 3-4 mm. long; style about twice as long as 

 the wing-margins. Thelypodium crenatum Greene. Sage plains: Colo. Son. Jl. 



6. L. scopulorum M. E. Jones. Somewhat woody at the base; stems 

 several, rather simple, glabrous, 1.5-3 dm. high; leaves coriaceous, glabrous, 

 shining, with broad, obovate, entire or round-toothed divisions; petals clawed, 

 2 mm. long; pod 3-4 mm. long, ovate; style 1 mm. long. Mountains: Utah 

 Ariz. (? Wyo.) Submont. Mont. Jl-Au. 



7. L. Crandallii Rydb. Stems several, branched and leafy throughout, 

 glabrous or puberulent above, 3-5 dm. high; lower leaves pinnatifid, 5-7 cm. long, 

 glabrous, with oblanceolate or oblong, entire or slightly toothed divisions; upper 

 stem-leaves oblanceolate or linear, entire or toothed; petals clawed, about 3 

 mm. long, white; pods oval or ovate, about 4 mm. long, glabrous, slightly wing- 

 margined above; style 1 mm. long. Valleys: Colo. Submont. My-Je. 



8. L. montanum Nutt. Stems often several from the same root, 2-4 dm. 

 high, more or less puberulent orhirsutulous; lower leaves bipinnatifid, with oblong 

 or obovate divisions, the upper pinnatifid or toothed; petals clawed, 2 mm. long; 

 pod ovate, 3-3.5 mrn. long; style about 0.75 mm. long. (?) L. philonitrum Nels. 

 & Macb. Plains: Wyo. N.M. Calif. Ida.; Mex. Son. Mont. My-S. 



