372 BIRTHWORT FAMILY. 



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

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

 5 -angled. 



-- -- BLACK BINDWEED. Stems twining, not prickly ; flowers whitish, in 

 loose, panicled racemes / three outermost of the 5 divisions of the calyx 

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

 gular. 



P. Convdlvulus, Linn. BLACK BINDWEED. Low twining or spreading 

 weed from Eu., in cultivated fields, etc.; smoothish, with heart-shaped 

 and almost halberd-shaped leaves, and very small flowers. 



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

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

 sepals hardly keeled. 2Z 



P. dumetdrum, Linn., var. scdndens, Gray. CLIMBING FALSE BUCK- 

 WHEAT. Moist thickets ; tall-twining, (J-12, smooth ; joints naked ; 

 leaves heart-shaped or approaching halberd-shaped ; panicles leafy ; outer 

 sepals strongly keeled and in fruit irregularly winged. 2/ 



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

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

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

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

 342, 344.) 



F. esculentum, Mcench. COMMON B. Nearly smooth ; leaves triangular- 

 heart-shaped, inclining to halberd-shaped or arrow-shaped, on Ion'; 

 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, Gaertn. TARTARY or INDIAN WHEAT. Cult, for flour ; like 

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

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



5. FOLYGONELLA. (Diminutive of Polygonum.) 



P. articulita, 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 with 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. 



XCVH. AKISTOLOCHIACEjE, BIKTHWOBT FAMILY. 



Known from all other apetalous orders by the numerous 

 ovules and seeds in a 6-celled ovary, to which the lower part 

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

 stamens generally 6 or 12, and more or less united with the 

 style. Anthers adnate and turned outwards. Calyx dull- 

 colored, valvate in the bud. Leaves petioled, usually heart- 

 shaped, not serrate. Flowers solitary, perfect, commonly 

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

 matic plants. 



