418 POLYGONACE^E. (BUCKWHEAT FAMILY.) 



Nutt. F. aviculare, var. littorale, Ed. 2.) Sandy sea-beach, Mass, to Virginia 

 and southward : at the north apparently only annual. (Eu.) 



1 6. P. ramosissimum, Michx. Stems erect or ascending, much branched 

 (2 -4 high), rigid, many-striate ; leaves lanceolate or linear, tapering into a 

 petiole; sheaths mostly short; calyx (drying yellowish) 6-parted and with 6 or 3 

 stamens, or 5-parted and with 4 or 5 stamens ; achenium very smooth and shining. 

 Sandy shores and banks of streams, Michigan to Illinois and southward. 

 Salt marshes, Rhode Island, Olney. Larger leaves 2' long. 



17. P. t6nue, Michx. Stemslender, upright, sparingly branched (6'-12' high), 

 sharp-angled ; leaves sessile, narrowly linear, very acute ; sheaths capillary fringed ; 

 flowers axillary and loosely spiked on the filiform branches ; achenium smooth and 

 shining. Dry soil, and rocky hills. 



6. TINLARIA, Meisn. Calyx 5-parted (rarely 4-parted), greenish tinged with 

 rose-color or white : stamens mostly S : styles or capitate stigmas 3 and achenium 

 3-sided (except in No. 18) : leaves heart-shaped or arrow-shaped, petioled: sheaths 

 semicylindricaL 



# Annuals, erect or somewhat climbing by the reflexed prickles which beset the angles 



of the stem and petioles: divisions of the (pale rose-colored or white) calyx not 

 keeled: bracts chaff-like. 



18. P. arif61ium, L. (HALBERD-LEAVED TEAR-THUMB.) Stem grooved- 

 angled; leaves halberd-shaped, taper-pointed, long-petioled ; flowers somewhat ra- 

 cemed (few) ; peduncles glandular-bristly ; calyx often 4-parted ; stamens 6 ; styles 

 2, .very short; achenium lenticular (large). Low grounds. 



19. P. sagittatum, L. (ARROW-LEAVED TEAR-THUMB.) Sterna-angled; 

 leaves arrow-shaped, short-petioled ; flowers capitate; peduncles smooth; stamens 

 mostly 8 ; styles 3, slender ; achenium sharply 3-angled. Low grounds : common. 

 Slender, smooth except the angles of the stem and midrib beneath : these are 

 armed with a line of fine and very sharp saw-toothed prickles, which cut the 

 hand drawn against them. 



* # Stems twining, not prickly : calyx with the 3 outer divisions keeled, at least in 



fruit : flowers in loose panicled racemes : bracts like the stipules. 



20. P. CONVOLVULUS, L. (BLACK BINDWEED.) Annual; stems twining 

 or procumbent, low, roughish, the joints naked; leaves halberd-heart-shaped, 

 pointed ; flowers in small interrupted corymbose racemes ; outer calyx-lobes keeled; 

 achenium smoothish. Cult, and waste grounds : common. (Nat. from Eu.) 



21. P. cilinbde, Michx. Perennial, minutely downy ; the sheaths fringed at 

 the base with reflexed bristles ; leaves heart-shaped and slightly halberd-shaped, 

 taper-pointed; racemes panicled; calyx-lobes obscurely keeled; achenium very 

 smooth and shining. Copses and rocky hills. Climbing 3 - 9 high. 



22. P. dumetbrum, L. (CLIMBING FALSE BUCKWHEAT.) Perennial, 

 smooth; sheaths naked ; leaves heart-shaped or slightly halberd-shaped, pointed; 

 racemes interrupted, leafy ; the 3 outer calyx-lobe.s strongly keeled and in fruit 

 winged; achenium smooth and shining. (Eu.) 



Var. scandens (P. scandens, Z.) has more panicled flowers, and usually 

 much broader wings to the fruiting calyx than the European. Moist thickets. 

 Twining 8 -12 high over bushes. 



