POLYGONACEAE (BUCKWHEAT FAMILY) 353 



Var. hastata (Nutt.) Duchartre. Leaves narrow, lanceolate or linear- 

 oblong, sagittate or auriculate-hastate. (A. hastata Nutt. ; A. Nashii Kearney.) 

 S. C. to Fla. and La. ; said to reach our southern limit in Va. 



* * Calyx-tube strongly curved like a Dutch pipe, contracted at the mouth, the 



short limb obscurely 3-lobed ; very tall twining shrubs. 



2. A. macrophylla Lam. (PIPE VINE, DUTCHMAN'S PIPE.) Nearly gla- 

 brous; leaves round-kidney-shaped (sometimes 4 dm. broad); peduncles with a 

 clasping bract ; calyx (3 cm. long) with a brown-purple abrupt flat border. (A. 

 Sipho L'He"r.) Rich woods, Pa. to Ga., w. to Minn, and Kan. May. 



3. A. tomentbsa Sims. Downy or soft-hairy; leaves round-heart-shaped, 

 very veiny (8-16 cm. long) ; calyx yellowish with an oblique dark purple closed 

 orifice and a rugose reflexed limb. Rich woods, N. C. to Fla., w. to s. 111. and 

 Mo. June. 



* * * Calyx-tube straight, open, with ample 6-lobed limb, the lobes appendaged; 



anthers equidistant; erect herbs ; flowers in axillary cymose fascicles. 



4. A. CLEMATITIS L., with long-petioled cordate leaves, sometimes cultivated, 

 has become locally established in the Atlantic States from N. Y. to Md. (Introd. 

 from Eu.) 



POLYGONACEAE (BUCKWHEAT FAMILY) 



Herbs, with alternate entire leaves, and stipules in the form of sheaths (ocreae, 

 these sometimes obsolete) above the swollen joints of the stem ; the flowers mostly 

 perfect, with a more or less persistent calyx, a \-celled ovary bearing 2 or 3 styles 

 or stigmas, and a single erect orthotropous seed. Fruit usually an achene, com- 

 pressed or 3-4-angled or -winged. Stamens 4-12, inserted on the base of the 

 3-6-cleft calyx. 



* Flowers involucrate ; stamens 9 ; stipules none. 



1. Eriogonum. Involucre several-flowered, with flowers exserted. Calyx 6-cleft. 



* * Flowers without involucre ; stamens 4 to 8. 



+- Stipular sheaths manifest ; ovule erect from the base of the cell. 



H- Sepals 4 or 6, the outer row reflexed, the inner erect and enlarging in fruit. 



2. Oxyria. Sepals 4. Stigmas 2. Achene orbicular-winged. Leaves reniform. 



3. Rumex. Sepals 6. Stigmas 3. Achene 3-angled. 



-n- -H- Sepals 5 (sometimes 4), equal and erect in fruit ; achene triangular or lenticular. 



4. Polygonum. Embryo slender, curved around one side of the albumen. Achenes inclosed by 



the somewhat enlarged fruiting calyx (or exserted in a few species with lanceolate or 

 linear leaves). 



5. Fagopyrum. Embryo in the albumen, its very broad cotyledons twisted -plaited. Fruit much 



exserted from the scarcely enlarged calyx. Leaves deltoid, sagittate or hastate. 

 C. Polygonella. Embryo slender, nearly straight. Pedicels solitary. Leaves linear, riant 



heath-like. 



-- -i- Stipules obsolete ; ovule hanging from the apex of a slender stalk. 

 7. Brunnichia. Calyx 5-parted, in fruit with a wing decurrenton the pedicel. Tendril-climber. 







1. ERIOGONUM Michx. 



Flowers perfect, involucrate ; involucre 4-8-toothed or -lobed, usually many- 

 flowered ; the more or less exserted pedicels intermixed with narrow scarious 

 bracts. Calyx 6-parted or -cleft, colored, persistent about the achene. Stamens 

 9, upon the base of the calyx. Styles 3 ; stigmas capitate. " Achene triangular. 

 Embryo straight and axial, with foliaceous cotyledons. Leaves entire, without 

 stipules. (Name from epiov, wool, and 76, knee.) 



1. E. Iongif61ium Nutt. Perennial, erect ; leaves oblanceolate, acute or 

 acutish, canescent beneath, the lower cuneate at base; sepals linear, caudate- 



GRAY'S MANUAL 23 



