IPOLYGONACE^E. 11 



ORDER LXXI V. POLYGONA'CE JE. (BUCKWHEAT F. ) 



Herbs, well marked by the stipules of the alternate leaves being 

 in the form of membranous sheaths above the usually swollen joints 

 of the *tem. Flowers usually perfect. Calyx 4-6-parted. Sta- 

 meus 4-9, inserted on the base of the calyx. Stigmas 2 or 3. 

 Ovary 1 -celled, with a single ovule rising from the base, forming 

 a little nutlet. 



Synopsis of the Genera. 



1. Polyg'onum. Sepals 5 (occasionally 4), often coloured and petal-like, 



persistent, embracing the 3-angled (or sometimes flattish) nutlet or 

 achene. Flowers in racemes or spikes, or sometimes in the axils. 



2. Ru'mex. Sepals 6, the 3 outer ones herbaceous and spreading in fruit, the 



3 inner (called valves) somewhat petal like and, after flowering, conver- 

 gent over the 3-angled achene, often with a grain-like projection on the 

 back. Stamens 6. Styles 3. Flowers usually in crowded whorls, the 

 latter in panicled racemes. 



3. Fagopy'rum. Calyx 5-parted, petal-like. Stamens 8, with 8 yellow 



glands between them. Styles 3. Achene 3-angled. Flowers white, in 

 panicles. Leaves triangular heart-shaped or halberd -shaped. 



1. POLYG'ONUM, L. KNOTWEED. 



* Flowers along the stem, inconspicuous, greenish- white, nearly sessile in the 

 axils of the small leaves. Sheaths cut-fringed or torn. 



1. P. avicula're, L. (KNOTGRASS. GOOSEGRASS.) A weed 

 everywhere in yards and waste places. Stem prostrate and 

 spreading. Stamens chiefly 5. Achene 3-sided, dull. Stigmas 3. 

 Leaves sessile, lanceolate or oblong. Var. erectum is upright 

 and larger, with broader leaves. 



2. P. ten'lie, Michx. Stem slender, upright, sparingly branched. 

 Leaves sessile, narrowly linear, very acute. Achene smooth and 

 shining. Dry soil and rocky places. 



* * Flowers in terminal spikes or racemes, mostly rose-coloured or pinkish, 

 occasionally greenish. 



-- Leaves not heart-shaped or arrow-shaped. 



3. P. incarna turn, Ell. Sheatlis not fringed. Stem nearly 

 smooth, 3-6 feet high. Leaves long, tapering from near the base 

 to a narrow point, rough on the midrib and margins. Spikes 

 linear and nodding. Stamens 6. Styles 2. Achene flat or hollow- 

 sided. In muddy places along streams and ponds. 



