POLYGOXACEAE. 



VOL. I. 



Over 200 species, natives of America, mostly of the western United States. Type species : 

 Eriogonum tomentosum Michx. 



Achenes 3-winged. i. E. alatum. 



Achenes merely angled, never winged. 

 Calyx contracted into a stipe-like base. 



Caulescent ; stems topped by compound cymes. 



Stem leaves alternate. 2. E. longifolium. 



Stem leaves opposite or whorled. 



Calyx yellow ; basal leaves rounded at the base ; Alleghanian. 3. E. Alleni. 

 Calyx white or pink ; basal leaves narrowed at the base ; campestrian. 4. E.Jamesii. 

 Scapose ; stems topped by simple umbels. 5. E.flavum. 



Calyx jointed to the pedicel without a stipe-like base. 

 Scapes or peduncles topped by capitate clusters. 



Calyx glabrous; achenes over 2 mm. long. 6. E. paiiciflorum. 



Calyx villous; achenes less than 2 mm. long. 7. E. multiceps. 



Scapes or peduncles topped by more or less compound cymes. 

 Involucres erect or at least never drooping. 



Ovaries and achenes completely clothed with wool ; leaf-blades silky above with silvery 



hairs. 8. E. lachnogynum. 



Ovaries and achenes glabrous or villous at the top ; leaf-blades more or less floccose. 

 Annual ; herbaceous throughout and usually simple at the base. 9. E. annuum. 

 Perennial ; shrubby and much branched at the base. 



Calyx yellow. 10. E. campanulatum. 



Calyx white, pink or reddish. 



Leaf-blades copiously pubescent on both sides. u. E.corymbosum. 



Leaf-blades densely pubescent beneath, inconspicuously so above. 

 Inflorescence 2-3 times compound ; branches spreading. 



12. E. microthecum. 

 Inflorescence 5-7 times compound ; branches erect or nearly so. 



13. E. effusum. 

 Involucres on drooping or deflexed peduncles. 14. E. cernuum. 



i. Eriogonum alatum Torr. Winged 

 Eriogonum. Fig. 1583. 



E. alatum Torr. SHgreaves' Rep. 168. pi. 8. 1853. 



Perennial by a long thick root, stem rather stout, 

 erect, strigose, paniculately branched, somewhat angled, 

 l-3 tall. Leaves mostly basal, spatulate, oblanceolate 

 or narrowly obovate, i'-3' long, those of the stem alter- 

 nate, nearly linear, short-petioled, all obtuse or subacute 

 at the apex, glabrous or pubescent and with midrib 

 prominent beneath, ciliate ; panicle open ; bracts lanceo- 

 late or subulate; involucres cymose at the ends of the 

 branches, campanulate, 5-toothed, i"-ii" long, the seg- 

 ments obtuse and somewhat reflexed; calyx yellowish, 

 i" long, campanulate; stamens slightly exserted; achene 

 long-pointed, 2<r"-3" long, reticulated, closely invested 

 by 3 wings. 



On plains, western Nebraska to Texas, west to Colorado 

 and New Mexico. June-Sept. 



2. Eriogonum longifolium Nutt. Long- 

 leaved Eriogonum. Fig. 1584. 



Eriogonnm longifolium Nutt. Trans. Am. Phil. Soc. 



(II.) 5: 164. 1833-37. 

 E. Texanum Scheele, Linnaea 22: 150. 1849. 



Perennial, strigose throughout, stem stout, 

 erect, paniculately or corymbosely branched, 

 leafy, finely grooved, 2-4 tall. Leaves nar- 

 rowly oblong or linear-oblong, obtuse at the 

 apex, more or less tomentose beneath, the upper 

 sessile, the lower narrowed into petioles with 

 dilated and sheathing bases ; bracts lanceolate 

 or subulate ; involucres turbinate-campanulate, 

 \\"-2." long; peduncles i' long or less; calyx 

 oblong-campanulate, 2"-3" high, 6-parted to 

 near the base, very villous ; stamens and style- 

 branches exserted ; achene 2\" long, much en- 

 larged at the base, villous, loosely invested by 

 the calyx-segments, not winged. 



Southern Missouri to Texas. June-Nov. 



