148 POLYGONACEAE (BUCKWHEAT FAMILY) 



BRACTS TERNATE, NOT FOLIACEOUS. 

 FLOWERS NOT YELLOW. 



Peduncles unbranched, terminated by a capitate cluster 



of involucres. 

 Leaves white-tomentose. 

 Oval or elliptic. 



Outer perianth-segments suborbicular . . 19. E. ovalifolium. 

 Outer perianth-segments oblong . . . 20. E. ochroleucum. 



Oblanceolate . . . . . . . 21. E. multiceps. 



Leaves glabrate above, linear ..... 22. E. pauciflorum. 



Peduncles branching di- or trichotomously, often sev- 

 eral times. 



Caudex subterranean; leaves clustered on its crowns. 

 Peduncle simple or simply dichotomous. 



Sepals dissimilar ...... 23. E. tenellum. 



Sepals similar ....... 24. E. racemosum. 



Peduncle di- or trichotomously branched . . 25. E. Simpsonii. 

 Caudex woody, branched, leafy. 



Branches few, erect, leafy up to the short corymbose 



cyme. 



Leaves elliptic, undulate-dentate . . . 6. E. Jonesii. 

 Leaves linear-oblong, entire .... 27. E. salinum. 



Branches numerous; peduncle long and naked, 



bearing a repeatedly forked cyme. 

 Styles and stamens included .... 28. E. effusum. 



Styles exserted ....... 29. E. corymbosum. 



FLOWERS YELLOW. 



Involucres in terminal capitate clusters. 

 Leaves short, less than 2 cm. 



Oval to elliptic 19. E. ovalifolium. 



Oblong. 



Ovary pubescent above ..... 30. E. caespitosum. 



Ovary glabrous . . . . . . 31. E. andinum. 



Leaves 4-8 cm. long, oblanceolate .... 32. E. chrysocephalum. 



Involucres in a dichotomous cyme. 



Cyme short, subumbellate ..... 33. E. orendense. 



Cyme long, freely branched ..... 34. E. campanulatum. 



1. Eriogonum annum Nutt. Trans. Am. Phil. Soc. II. 5: 164. 1833-37. 

 Annual, white floccose-tomentose throughout, rather stout, simple or branched, 

 3-8 dm. high: leaves narrowly oblanceolate or oblong, attenuate to a short 

 petiole, mostly flat: inflorescence cymose: the flowers white: the perianth- 

 segments very unequal, the outer oblong-obovate. Montana to Texas and 

 Mexico. 



2. Eriogonum salsuginosum Hook. Kew Journ. 5: 264. 1853. Low gla- 

 brous annual 4-12 cm. high: stem leafy, di- or trichotomously divided: leaves 

 spatulate-oblanceolate, the bracts becoming linear: involucres divided: 

 flowers pubescent, yellow: sepals narrow, closely appressed to the acutely 

 triangular glabrous achene. From southwestern Colorado to Utah and west- 

 ern Wyoming. 



3. Eriogonum inflatum Torr. Frem. 2d Rep. 374. 1845. Glabrous annual, 

 diffusely branched above, 1-3 dm. high, one or more of the internodes of the 

 stem much inflated: leaves all radical or nearly so, rounded, usually cordate 

 and mostly undulate, pubescent: involucres few-flowered, smooth; the teeth 

 erect: flowers yellowish, pubescent; the pedicels about 1 mm. long; the achene 

 twice as long. (E.fusiforme Small, Bull. Torr. Bot. Club 33: 56. 1906.) In 

 dry desert districts; southwestern Colorado to Arizona. 



4. Eriogonum Gordonii Benth. in DC. Prodr. 14: 20. 1856. Annual, gla- 

 brous throughout, or the petioles slightly pubescent: leaves basal, long- 

 petioled, broadly ovate: peduncle di- or trichotomously slender branched, 

 15-30 cm. high: involucre broadly campanulate, 5-toothed: flowers glabrous, 

 light rose-color: outer sepals ovate; the inner oblong. Rare; in the region of 

 the Platte in Nebraska, and in Colorado and Wyoming. 



5. Eriogonum cernuum Nutt. Journ. Acad. Phila. II. 1: 162. 1848. Gla- 

 brous annual, diffusely di- or trichotomously branched, 1-3 dm. high: leaves 

 broadly ovate, acute: involucres turbinate-campanulate: pedicels dellexed: ca- 

 lyx white, campanulate, 1 mm. long, 6-parted; the segments narrowed near 

 middle; the outer ones broader above and retuse: achene rounded at base and 

 rough on the angles. Frequent throughout our rango. 



