BUCKWHEAT FAMILY. 287 



2. CELOSIA, COCKSCOMB. (Name in Greek means dried, alluding to 



the scarious bracts.) Fl. summer. (T) 



C. erist^ta. Common C. of the gardens, from India, in various usually 

 monstrous forms, the showy flower-crests crimson-red, sometimes rose-colored, 

 yellow, or wliite. 



3. GOMPHRENA. (Ancient name of an Amaranth.) FI. summer. 



G. glob6sa, Globe Amaranth or Baciielor's-Button. Cult, from 

 India : low, branching, pubescent, with oblong nearly sessile leaves, and dens? 

 round heads crimson, rose-color, or white. 



95. POLYGONACE-aS, BUCKWHEAT FAMILY. 



Known by the alternate entire leaves having stipules in the form 

 of scarious or membranous sheaths at the strongly marked usually 

 tumid joints of the stem. Flowers mostly perfect, on jointed pedi- 

 cels, with green or colored 4 — 6-parted usually persistent or wither- 

 ing calyx, 4-9 stamens on its base, 2 or 3 stigmas, 1 -celled ovary 

 with a single ovule rising from its base (Lessons, p. 122, fig. 268), 

 forming an akene or nutlet. Embryo mostly on the outside of 

 mealy albumen, the radicle pointing to the apex of the fruit. 



Eriogonum differs in having no obvious stipules, and the 

 flowers from a cup-shaped involucre. There are a few species 

 of the genus S. and S. W., and many near and beyond the Rocky 

 Mountains. 



§ 1. Calyx ofb, rarely 4, tnore or less petal-like similar sepals, erect after flowering. 



1. POLYGONUM. Flowers in racemes, spikes, or else in the axils of the leaves. 



Akene either lenticular when there are 2 stigmas, or triangular when there 

 are 3. Embryo curved round one side of the albumen : cotyledons narrow. 



2. FAGOPYRUM. Differs from one section of Polygonum mainly in having an 



embryo in the centre of the albumen, which is divided into 2 parts by the 

 very broad leaf-like cotyledons. The triangular akene longer than the calyx. 



§ 2. Calyx of 6 sepals often of two sorts : styles 3. 

 8. RHEUM. Sepals all similar, petal-like, withering-persistent underneath the 

 3-winged fruit. Stigmas capitate or wedge-shaped. Stamens 9. 



4. RUMEX. Sepals of 2 sorts; the 3 outer ones herbaceous and at length spread- 



ing ; the alternate inner 3 larger, somewliat colored, enlarging after flowering, 

 becoming veiny and dry, often bearing a grain-like tubercle on the back, and 

 convergent over the 3-angled akene. Stigmas a hairy tuft. Stamens 6. 



1. POLYGONUM, KNOTWEED, JOINTWEED. (The name in Greek 

 means many-jointed.) Chiefly weeds ; some with rather showy flowers ; the 

 following are the commonest : fl. late summer and autumn. 



§ 1. Flowers along the stem, nearh/ sessile in the axils of the almost sessile linear or 

 oblong leaves, small, greenish-white : sheaths scarious, usually cleft or torn 

 and fringed. ® 



P. avicul^e, Knot-grass, Goose-grass, or Doorweed. Prostrate 

 or spreading and variable low weed, with pale lanceolate or oblong leaves, 

 cornmonly 5 stamens, and dull 3-sided akene enclosed in the calyx. Var. 

 erectum, has more upright stems, and larger oblong or oval leaves. 



P. ramoslssimum. Chietly W. in sandy soil : with nearly erect much- 

 branched and rigid striate stems 2° -4° high ; lanceolate or linear leaves taper- 

 ing into a ])Ctiole, and a glossy akene ; sepals 6 and stamens 6 or 3, or else 

 sepals 5 with 4 or 5 stamens. 



