Flora of the Palonse Region 87 



partition; valves more or less 1 -nerved; seeds flattened, usually 

 winged, in one or two rows. 



Flowers whitish: upper leaves glabrous and glaucous. A. pp;rfoliata. 

 Flowers red: pubescent throughout. 



Pubescence coarse: pods recurved-spreading. A. arci-ata. 



Pubescence fine: pods abruptly reflexed. A. holboeu.ii. 



A- perfoliata Lam. Biennial, pubescent near the base, glabrous and 

 glaucous above: stems usually simple, 60-90 cm. high: basal leaves oblan- 

 ceolate, dentate or pinnatfid, pubescent, 5-8 cm. long; cauline oblong-lan- 

 ceolate, sessile, sagittate and auricled at base, all but the lower glabrous: 

 flowers whitish about .5 mm. long: pods erect or ascending, linear, 4-10 cm. 

 long, tipped with the large 2-lobed sessile stigma; pedicels 4-10 mm. long. 

 Low ground, not common. 



A. arcuata var. subvillosa Wats. Perennial, roughly stellate-pubescent 

 below, glabrous above: stems mostly simple, erect, 30-60 cm. high: radical 

 leaves linear, oblanceolate, dentate, petioled; cauline lanceolate, subentire, 

 sessile, with a sagittate base: flowers rose-colored: pods recurved, 5-8 cm. 

 long, linear, acute; pedicels pubescent, 6-12 mm. long. Basalt ledges, com- 

 mon. 



A. holboellii Hornem. Much like the preceding, but the pubescence 

 much finer: pods sharply reflexed: flowers purple or nearly white. Basalt 

 ledges, not rare. 



141. ERYSIMUM. 



Biennial or perennial herbs: leaves narrow, entire or toothed, 

 not clasping: flowers often large, usually yellow: pod linear, 

 4-angled, not stipitate; valves keeled, with a prominent midrib; 

 seeds oblong, marginless, in one row in each cell. 



Flowers small: petals 4-5 mm. long. F. chf.iranThoides. 



Flowers large: petals 15-25 mm. long. E. ASPERt'M. 



E. cheiranthoides L. Erect, branched above, minutely rough-pubescent 

 throughout: leaves lanceolate, acute at each end, entire or minutely dentate, 

 sessile or nearly so: racemes elongate: petals 4-5 mm. long, yellow: pod lin- 

 ear, 4-angled, puberuleut, very short-beaked, about 2 cm. long, erect, on 

 spreading pedicels about 1 em. long. Very sparingly introduced. 



E. asperum DC. Whitish throughout with appressed pubescence: stems 

 simple, stout, 20-40 em. tall, erect: leaves lanceolate or oblanceolate, entire 

 or somewhat dentate, rarely lobed, mostly petioled, 6-10 cm. long: flowers 

 bright yellow: petals 1.5-2.5 cm. long: pods stout, somewhat 4-angled, about 

 8 cm. long, tipped with a short stout beak and a large 2-lobed Stigma; pedi- 

 cels stout, 1 cm. long. Bluffs of Snake River. 



142. ALYSSUM. 



L/Ow branching annual herbs: leaves mostly simple: flowers 

 yellow: style slender: pod ovoid or orbicular, compressed; 

 valves convex, nerveless; seeds one or two in each cell. 



