324 BRASSICACEAE 



3. LEPIDIUM L. Peppergrass, Canary-grass, Bird-seed. 



Annual, biennial or perennial herbs. Pubescence if any of simple hairs. 

 Leaves alternate, entire, toothed, lobecl, or dissected. l<lowers perfect, in 

 racemes or panicles. Sepals 4, equal. Petals small, white or greenish, or want- 

 ing. Stamens often less than G. Ovary sessile; styles short or wanting; ovules 

 solitary in each cell, pendulous. Pods short, oblong to orbicular, transversely 

 flattened, wing-margined or at least acute on the margins, notched at the apex. 

 Seeds solitary in each cavity. Cotjdedons incumbent or rarely obliquely ac- 

 cumbent. 



Style evident, at least equalling the wing-margins. 

 Introduced annuals or biennials. 



Upper leaves entire, perfoUately clasping. 1. L. perfoliatum. 



Leaves all pinnatifld, none clasping. 2. L. sativum. 



Native perennials. 



Pods 2-4 mm. wide. 



None of the leaves pinnatifld. 



Basal leaves oblanceolate, entire-margined, thick; stamens 2. 



3. L. iniegri folium. 

 Basal leaves more or less toothed, tliinner; stamens 6. 



Basal leaves truncate and 3-toothed at the apex. 4. L. Vaseyanum. 

 Basal leaves oblanceolate, acute at the apex, serrate-crenate. 



5. L. crenatum. 

 Basal leaves at least pinnatifld. 



Segments of the basal leaves short, obovate or oblanceolate in outline; 

 petals obovate. 

 Styles 2-3 times as long as the wing-margins; racemes in age more or 

 less elongate. 

 Styles about 3 times as long as the wing-margins ; leaves coriaceous; 

 segments entire or merely round-toothed, obtusish; plant 

 glabrous; stem few-leaved. 6. L. scopulorum. 



Styles about 2 times as long as the wing-margins; leaves not cori- 

 aceous; segments usually cleft or deeply toothed, acute. 

 Upper stem-leaves Unear, entire; plant glabrous or the upper 



part of the stem sUghtly puberulent. 7. L. Crandallii. 

 Leaves usually all pinnatifld; stem puberulent throughout. 

 Stem gland ular-puberulent; pod oval or ovate, narrowed 



towards the apex. 8. L. montanum. 



Stem densely papillose-puberulent; pod orbicular. 



9. L. papilliferum. 

 Styles slightly exceeding the wing-margins; racemes numerous, short; 

 p],ant puberulent. 10. L. brachybptryum. 



Segments of the basal leaves elongate, linear, oblong, or lanceolate. 



Only the lower leaves pinnatifld; pod broadly oval; style scarcely 

 longer than the width of the wing-margins; petals orbicular. 



11. L. alyssoides. 

 Stem leaves except the uppermost also pinnatifld ; pod narrower, acutish 



at both ends; style about twice as long as the width of tlie wing- 

 margins; petals obovate to elliptic. 

 Plant low, 3 dm. high or less; leaves or their lobes narrowly linear. 



12. L. Jonesii. 

 Plant tall, 4-10 dm. high; upper leaves broadly linear or oblong. 



13. L. Eastwoodiae. 

 Pods 6-8 mm. wide. 14. L. Fremontii. 



Style obsolete, or at least shorter than the width of the wing-margins; annuals or bi- 

 ennials. 

 Wing-margins of the fruit not produced at the apex into distinct lobes or teeth. 

 Pods glabrous or rarely minutely puberulent when young. 



Petals conspicuous, at least equalling the sepals, spatulate or obovate. 



Style distinct, but short; blades of the petals broadly obovate, much ex- 

 ceeding the sepals. 15. L. idahoense. 

 Style none; blades of the petals spatulate. 



Pubescence, if any, of cylindrical or subulate hairs; petals well exceed- 

 ing tne sepals, at least in the earlier flowers. 

 Stem glabrous or nearly so. 



Cotyledons accumbent; petals broadly spatulate. 



16. L. virginicum. 

 Cotyledons incumbent; petals narrowly spatulate or oblance- 

 olate. 17. L. lexanum. 

 Stem densely pubescent. 18. L. hirsulum. 

 Pubescence of the stem of short, clavate hairs; petals about equaUing 

 the sepals. 

 Stem low, 1-3 dm. high, branched below; primary basal leaves 



oblanceolate, serrate. 19. L. ramosum. 



Stem taller, 4-6 dm. high, simple below, branched above; primary 

 basal leaves pinnatifld. 20. L. simile. 



Petals none or minute, scarcely more than half as long as the sepals, linear or 

 linear-spatulate. 



