388 POLYGON ACEiE. (BUCKWHEAT FAMILY.) 
and along streams. Aug. — Plant not acrid. Calyx rose-color or 
whitish, not dotted. 
9. P. amphibium, L. (Water Persicaria.) Leaves el¬ 
liptical-lanceolate or oblong, pointed or obtusish, either narrowed or 
rather heart-shaped at the base ; spikes very dense, ovoid or cylindri¬ 
cal; stamens 5; styles 2; fruit flattened, smooth. 1J.—Var. 1. 
aquaticum, L ., is floating or procumbent in soft mud, rooting, and 
nearly smooth, as well as the long-petioled often obtuse floating 
leaves. (P. coccineum, Bigd. P. fluitans, Eaton.) — Var. 2. ter- 
restre, Torr., is more or less hairy or bristly, with an upright or as¬ 
cending stem, growing in marshy or muddy places ; the leaves acute 
or pointed, upper very short-petioled.—Ponds or their low borders, 
New England to Wisconsin, the var. 1 chiefly northward. July, 
Aug. — Very variable in foliage, &c.: spike V - 3 f long, rose-red. 
§ 4. AviculIria, Meisn. — Calyx mostly petal-like, ^-parted: stamens 
8, sometimes 3-6; the filaments awl-shaped , 3 of them broader at the 
base: stigmas 3, globose, nearly sessile: achenium 3 -sided ( cotyle¬ 
dons incumbent): commonly annuals icith small leaves , smooth : flow¬ 
ers axillary, sometimes crowded in interrupted spikes along the leafless 
summit of the branches. 
* Flowers truly axillary , 2-3 together, or rarely solitary : sheaths usu¬ 
ally 2 - 3- parted and cut-fringed or tom. 
10. P. avtculare, L. (Knot-grass. Goose-grass. Door- 
weed.) Prostrate or spreading ; leaves sessile, lanceolate or 
pale; flowers apparently sessile (greenish-white, sometimes tinge 
with purple); sheaths much shorter than the lower leaves ; fruit tnr 
closed in the calyx , minutely wrinkled-striate, rather dull. — ^ ar - KREC 
tum, Roth. (P. erectum, L.), has upright or ascending stems, l ar n e ^ 
oval or elliptical leaves, and usually 5 stamens. — Road-sides an 
waste places, everywhere; the var. in more shady or damp 801 
introduced. June-November. 
11. P. inaritiiuuui, L. (Seaside Knot-grass.) Prostrat ^ 
with very short joints ; leaves lanceolate, glaucous, fleshy ; flowers o 
pedicels at length a little exserted beyond the conspicuous sheat s, 
which are about half the length of the leaves; fruit longer than te 
calyx, smooth and shining (twice or thrice as large as in the last). V2/ 
1|. ? (P. glaucum, JYutt.) — Sandy beach, Long Island, New Jersey, 
and southward. Aug. 
12. P. rainosissimiliii, Michx. (Upright Western Knot 
grass.) Stem tall, upright , paniculately much branched, many-stri 
leaves lanceolate, tapering into a petiole; sheaths short; flowers 
short exserted peduncles (greenish-white) ; fruit inclosed in the cu 
minutely wrinkled transversely. — Sandy shore of Lake Michigan aR 
southward. Aug., Sept. — Plant 2P high : stem-leaves 2' long- 0 ^ 
ers larger than in No. 10, in the axils of small leaves loosely di»p 0&e 
on the branchlets. 
