126 POLYGONACEAE. 



Outer perianth-segments broader than the inner. 



Involucre campanulate; perianth 3-4 mm. long. E. ovalifolium. 

 Involucre turbinate; perianth 5-6 mm. long. E. vineum. 



Perianth attenuate and stipe-like at base. 



Umbel compound; leaves oblong-ovate, usually cor- 

 date at base. E. composition. 

 Umbel simple; leaves not as above. 



Perianth yellow, glabrous; lobes of the involucre 



inflexed. E. umbellatum. 



Perianth pinkish, villous; lobes of the involucre 



erect. E. pyrolaefolinm. 



Eriogonum nudum Dougl. Leaves ovate or oblong, obtuse, tomentose 

 beneath, 2-5 cm. long, mostly basal, on slender petioles; stems 30-50 cm. high, 

 glabrous; panicle sparingly branched; involucres glabrous; flowers glabrous 

 or nearly so, white or rose-tinged, in clusters of 3-6. 



Upper Willamette Valley and southward. 



Eriogonum ovalifolium Nutt. A much branched tufted plant, densely 

 white-tomentose to the flowers; leaves broadly ovate or orbicular, obtuse, 

 5-12 mm. long; peduncles slender, 5-20 cm. high; involucres campanulate, 

 4-5 mm. long; flowers in a dense head-like umbel, usually yellowish, 3-5 

 mm. long. 



At high altitudes in the mountains. 



Eriogonum vineum Small. Very similar to E. ovalifolium; involucres 



turbinate or vase-shaped, 4.5-5.5 mm. long; perianth wine-red, 5-6 mm. long. 



In rocky soil at high altitudes. Perhaps not distinct from E. ovalifolium. 



Eriogonum compositum Dougl. Stems stout, simple, 20-30 cm. tall, 

 glabrous or nearly so; leaves ovate or oblong-ovate, cordate, acute, densely 

 white-woolly beneath, green and less so above, 4-10 cm. long, on petioles as 

 long or longer; umbels 6-10-rayed, mostly compound, rather dense; principal 

 bracts linear or oblanceolate; branches very short, 2-4 cm. long; involucres 

 pubescent, deeply 5-lobed, the lobes acute, spreading; flowers white or yellow, 

 sparsely pilose. 



In gravelly soil in open places. 



Eriogonum umbellatum Torr. (E. montanum Howell.) Stems woody 

 and much branched, 15-20 cm. high; leaves spatulate, the blade oblong to 

 orbicular, 1-4 cm. long, densely white tomentose beneath, green and glabrous 

 above; peduncles 10-30 cm. high, bearing a simple umbel of 3-10 rays with a 

 whorl of foliaceous bracts at the base; involucre turbinate, somewhat woolly, 

 deeply lobed, the lobes becoming reflexed; perianth bright-yellow, stipe-like 

 at base, 4-5 mm. long, glabrous. 



On the high peaks of the Cascade Mountains, perhaps only on the eastern 

 watershed. 



Eriogonum pyrolaefclium coryphaeum T. & G. Loosely tufted; leaves 

 oblong or obovate, densely tomentose beneath, greener above, 2-3 cm. long; 

 peduncles 5-8 cm. high, smooth; flowers rose-colored, in dense umbels; perianth 

 villous. 



At high elevations in the mountains. 



158. OXYRIA. 



Perennial alpine herbs with long-petioled mostly basal leaves; 

 stipules sheathing the stems; flowers perfect, without an invo- 

 lucre ; calyx of 4 distinct herbaceous sepals, the two outer spreading, 

 the inner erect; stamens 6; stigmas 2 ; akene compressed, 2 -winged. 



