54 2 POLYGONACEAE. 



i. Macounastrum Islandicum (L.) Small. 

 Macounastrum. (Fig. 1285.) 



Koenigia Islandica L. Mant. 35. 1767. 



Stems very slender, \'-\' long, sometimes tufted. 

 Leaves obovate, oblong or almost orbicular, i // -5 // 

 long, fleshy, obtuse at the apex, sessile or short-peti- 

 oled; ocreae about % ff long; involucre consisting of 

 3-6 obovate or orbicular leaves more or less united at 

 their bases; flowers fascicled in the involucres, short- 

 pedicelled; calyx y?," long, the segments ovate-lan- 

 ceolate, rather obtuse; stamens very short; style- 

 branches short; achene less than \" long, brown, 

 often slightly curved, striate, its faces convex. 



Greenland and Labrador to Hudson Bay and Alaska. 

 Also in arctic Europe and Asia. Summer. 



2. ERIOGONUM Michx. Fl. Bor. Am. i: 246. 1803. 



Annual or perennial acaulescent or leafy-stemmed herbs, some species very woody at 

 the base, with simple or branched, often tufted stems, and entire alternate opposite or whorled 

 leaves. Flowers small, fascicled, cymose, umbellate or capitate, subtended by 5-8-toothed 

 or cleft campanulate top-shaped or almost cylindric involucres. Calyx 6-cleft or 6-parted, 

 usually colored, the segments equal or the outer ones larger. Stamens 9, included or ex- 

 serted; filaments filiform, often villous; anthers oblong. Style 3-parted; stigmas capitate. 

 Achene pyramidal, 3-angled, more or less swollen near the base, invested by the calyx-seg- 

 ments, or winged. Embryo axial or somewhat eccentric. [Greek, referring to the woolly 

 and jointed stems.] 



About 160 species, natives of America, mostly of the western United States. 

 Stem leaf y to the summit. 



Stem leaves alternate; stem strigose. 

 Achene glabrous, winged in fruit. 

 Achene villous, not winged 

 Stem leaves whorled; stem tomentose. 



Robust; basal leaves rounded at the base; flowers yellow. 

 Slender; basal leaves narrowed at the base; flowers white or pink. 

 Stem leafy below, naked above. 



Involucres erect on branches of the cymes. 

 Involucres in axillary and terminal clusters. 



Leaves narrowly oblong or oblanceolate, flat, long-petioled. 

 Leaves oblong, more or less crisped, short-petioled. 

 Acaulescent; scapose; scapes more or less tufted. 

 Scape simple; inflorescence capitate. 



Densely tomentose; leaves spatulate, numerous. 

 Slightly tomentose; leaves linear or linear-spatulate, few. 

 Scape branched at the summit. 



Inflorescence regular^- umbellate. 



Inflorescence irregularly umbellate or paniculate. 



Inflorescence cymose. 



I.E. alatum. 



2. E. longifolium. 



3. E. All en i. 



4. E.Jamesii. 



5. E. an nun in. 



6. E. microthecum. 



7. E. corymbosum. 



E. mult ice ps. 

 E. paiicijlorum. 



10. E.flavHm. 



11. E. lachnogynitm. 



12. E. i am pa n u Fa tut 



Scape branched throughout; involucres solitary on deflexed peduncles. 13. E. cernuitin. 



i. Eriogonum alatum Torr. Winged 

 Eriogonum. (Fig. 1286.) 



E. alalum Torr. Sitgreaves' Rep. 168. pi. >. : 



Perennial by a long thick root, stem rather stoi 

 erect, strigose, paniculately branched, somewhat ang- 

 led, i-3 tall. Leaves mostly basal, spatulate, oblan- 

 ceolate or narrowh' obovate, 1'-$' long, those of the 

 stem alternate, nearly linear, short-petioled, all obtuse 

 or subacute at the apex, glabrous or pubescent and 

 with midrib prominent beneath, ciliate; panicle open; 

 bracts lanceolate or subulate; involucres cymose at the 

 ends of the branches, campanulate, 5-toothed, i"-i%" 

 long, the segments obtuse and somewhat reflexed; 

 calyx yellowish, \" long, campanulate; stamens 

 slightly exserted; achene long-pointed, 2_# // -3 // 

 long, reticulated, closely invested by 3 wings. 



On plains, western Nebraska to Texas, west to Colorado 

 and New Mexico. June-Sept. 



