Ir^OLYGONACEAE (BUCKWHEAT FAMILY; 855 



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

 oblong, sagittate or auricula te-hastate. {A. hastata Nutt. ; A. Nashii Kearney ^ 

 — tt. 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 S-lobed ; very tall twining shrubs. 



2. A. macrophylla Lam. (Pipe Vine, Dutchman's JMpe.) Nearly gla- 

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

 clasping bract ; calyx (8 cm. long) with a brown-purple abrupt flat border (A 

 Sipho L'H^r.) — Rich woods, Pa. to Ga., w. to Minn, and Kan. May. 



3. A. toment5sa Sims. Downy or soft-hair)^; leaves round-hmrt-shaped 

 very veiny (8-16 cm. long) ; ccciyx yellowish with an oblique dark purple clo.sed 

 orijice and a rugose reflexed limb. — llich woods, N. C. to ila., w. to s. 111. and 

 Mo. June. 



* * * Calyx-tube straight, open, with ample Q-Tobed 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 1-celled ovary bearing 2 or 3 styles 

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

 pressed or 8-4-angIed 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. 



++ Sepals 4 or 6, the outer row reflexed, the inner erect and enlarging in fhilt. 



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



3. Rumex. Sepals 6. Stigmas 3. Achene 8-angled. 



++ ++ 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 fi-uiting 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. 



6. Polygonella. Embryo slender, nearly straight. Pedicels solitary. Leaves linear. Plant 



heath-like. 



+- -8- 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-tootlied 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 tl)e calyx. Styles .■■> ; stigmas capitate. Achene triangular. 

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

 stipules. (Name from epiov. loooL and 761'^, knee.) 



I. E. longifblium Nutt. Perennial, erect ; leaves oblanceolate, acute 01 

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



GtRAY'S MANUAL— 23 



