390 rOLYGONACE^E. (BUCKWHEAT FAMILY.) 



§ 3. Avicri.ARiA. Floivers axillai-ij, single or 2-3 together: stamens 9., rarely 

 fewer: stiijmas 3, txar/i/ sessile : achenium 3-an(/led : cotijlidous imumienl: albu- 

 vun liornij : sliriitlis scarious, 2 ~3-parted, lacerated: Itaces small. 



10. P. aviculare, L. Stein prostrate, diflfuse, short-jointcil ; loaves sessile 

 (^' long), oblong-liiiciir or lanceolate, obtuse, longer than the 3-cUft slieaths ; 

 flowers clustered, nearly sessile, greenish-white, longer than the dull achenium ; 

 stamens mostly 5. — Waste places and along roads, common. — Var. ekicctum. 

 (I*, crectum, L.) Stem stouter, erect or ascending, leaves larger (1'- H' long), 

 ol)iong. — "With the preceding. — Var. littouale. (!'. maritinnim, L. P. 

 ghuicum, Nutt.) Stem long (1° -2°), prostrate, rigid, short-jointed; leaves 

 small (4''-C"), oblong-linear, glaucous; the upijcmiost imbricated and scarcely 

 longer than the more conspicuous silveiy sheaths ; calyx reddish-white, shorter 

 than the smootli achenium. — Sea-coast sands, Georgia, and northward. 



11. P. tenue, Michx. Smooth; stem erect, brancjicd, sharply angled, 

 slender; leaves scattered, linear, acute ; sheaths small, fringed ; flowers mostly 

 solitaiy, greenish-white ; achenium smooth and shining. — Dry rocks in the 

 upper districts. July - Sept. Q) — Stem 6' - 8' high. Leaves C" - 1 2" long. 



§ 4. TovAUiA. Flowers scattered in a long and slender splice: cali/.r A-parted: 

 stamens 5, included: stjles 2, exserted, persistent : achenium lenticular: cotyledons 

 accumhent. 



12. P. Virginianum, L. Stem erect, smooth below ; the upper portion, 

 like the leaves and spikes, more or less hairy ; leaves large, ovate or ovate-lance- 

 olate, acute at each end ; sheaths cylindrical, hairy, fringed ; flowers greenish, 

 curved; styles at length hooked at the apex. — Dry rich soil, Florida, and 

 northward. Aug. and Sept. ![ — Plant 2° -4° high. Leaves 3' -5' long, 

 l^'-2^'wide. Spike C- 12' long. 



§ 5. EcHiNOCAULOx. FlowcTs ill terminal clusters: cali/x 4 - 5-partcd : stamens 

 6 or 8 : sli/les 2-3 : achenium lenticular or 3-angled: cotyledons accumbent. — 

 Stems iceak, hninrhiiig, armed on the angles, petioles, ^c. xvith recurved prickles. 



13. P. arifolium, L. Leaves hastate, acuminate, membranaceous, mi- 

 nutely dotted and iiairy, long-petioled, the lobes acute ; peduncles rather short, 

 bristly; flowers white, somewhat spiked; stamens 6 ; styles 2; achenium len- 

 ticular. — Rico fields and wet places. South Carolina, and noriliwaid. June- 

 Oit. ® — Stems 2° -3° long. Leaves 3' -4' long. Calyx often 4-])arted. 



14. P. sagittatum, L. Leaves small, sagittate, acute, short-petioled, 

 smooth ; peduncles elongated, smooth ; flowers white, capitate ; stamens 8 ; 

 styles 3; achenium 3-angled. — Wet places, Florida, and northward. Juno- 

 Oct Qj— Stem l°-3° long. Leaves 1'- 2' long. 



I) 6. TiNiAitiA. Flowers in axillary clusters or racemes: calyx greenish white, 

 f}-parled, the outer lohts keeled or winged on the hielc : stamens 8 : styles 3, fery 

 short: achenium 3-angled; cotyledons accumbent. — Annuals, with twining stems 

 and cordate haves. 



15. P. Convolvulus, L. Stem roughish, prostrate or twiiiiiiff, or when 

 tiiiiall erect; leaves long-petioled, sagittate-cordate, albuminate, th(t lobes ucutc or 



