372 KIRTHWOUT FAMILY. 



P. sagittatum, Linn. Low grounds ; leaves arrow-shaped, short-peti- 

 oltd ; the peduncles naked ; stamens mostly 8 ; styles 3 ; akene sharply 

 5-angled. 



■t- -t- Black Bindweep. Stems twining, not prickly ; flowers tchitish, in 

 loose, panicled racemes; three outermost of the o divisions of the calyx 

 keeled or crested, at least in fruit ; stamens 8 ; styles 3 ; akenes trian- 

 gular. 



P. Conv6lvulus, Linn. Black Bindweed. Low twining or spreading 

 weed trom Eu., in cultivated iiekls, etc.; smoothish, with heart-shaped 

 and almost halberd-shaped leaves, and very small flowers, (i) 



P. cilin6de, .Michx. Rocky shady places ; tall-twining, rather downy ; 

 a ring of retiexed bristles at the joints ; leaves angled-heart-shaped ; outer 

 sepals hardly keeled. H 



P. dumet6rum, Linn., var. scdndens, Gray. Climbing False Bcck- 

 wiii:at. Moist tliickets ; tall-twining, G°-12°, smooth; joints naked; 

 leaves heart-.shaped or approaching halberd-shaped ; paniides leafy ; outer 

 sepals strongly keeled and in fruit irregularly wingeii. 11 



4. PAGOPYRUM, BUCKWHEAT. (The botanical name, from the 

 Greek, and the popular name, from the German, both denote Beech- 

 icheat, the grain resembling a diminutive beech-nut.) Cult, from N. 

 Asia, for the flour of its grain; flowers summer. (Lessons, Fig. 

 342, 344.) 



F. esculentum, Moench. Common B. Nearly smooth ; leaves triangular- 

 heart-shaped, inclining to halberd-shaped or arrow-shaped, on long 

 petioles ; sheaths half-cylindrical ; flowers white or nearly so, in corym- 

 bose panicles ; stamens 8, with as many honey-bearing glands interposed ; 

 styles 3 ; acutely triangular akene large. 



F. Tatdricum, Gxitn. Tartary or Indian Wheat. Cult, for flour ; like 

 the other, but flowers smaller and tinged with yellowish ; gram smaller, 

 with its less acute angles wavy, dull, and roughish. 



5. POLYGONIJLLA. (Diminutive of Polygoiuim.) 



P. articulata, Meisn. A slender little plant, bushy-branching, 4'-12' 

 high ; leaves small and thread-like or at length none ; the sheaths trun- 

 cate, naked, rigid ; many-jointed raceme witii a single flower under each 

 bract ; flowers rose- colored, nodding ; stamens 8 ; akene triangular. 

 Sandy dry soils, on the coast, Me., S., and along the Great Lakes, 



XCVII. ARISTOLOCHIACEiE, lURTHWORT FAMILY. 



Known from all other apetalous orders by the numerous 

 ovules and seeds in a G-celled ovary, to whicli the lower part 

 of the lurid calyx is adherent, the latter mostly 3-lobed, the 

 stamens generally G or 12, and more or less united with the 

 style. Anthers adnate and turned outwards. Calyx dull- 

 colored, valvate in tlie V)ud, Leaves petioled, usually heart- 

 shaped, not serrate. Flowers solitary, perfect, commonly 

 large and odd. Litter, tonic or stimulant, sometimes aro- 

 matic plants. 



