PERSICARIA FAMILY 417 



ochreate stipules ; flowers perfect, in spikes, racemes, or panicles ; 

 perianth deeply 5-cleft, the 3 outer segments sometimes enlarging 

 in the fruiting stage ; stamens 5 — 8, with versatile anthers ; ovary 

 compressed or 3-sided ; styles 2 — 3 ; fruit not winged ; embryo 

 lateral ; cotyledons thin, flat. (Name from the Greek p'olus, many, 

 gonu, knee, from the many knee-like nodes.) 



* Twining plants ; leaves sagittate ; flowers in racemes ; stamens 8 ; 

 styles 3, united ; nut ysided 



1. P. Convolvulus (Black Bindweed, Climbing Buckwheat, or 

 Persicaria). — A mis- 

 chievous weed with 

 the habit of the Field 

 Convolvulus (Con- 

 volvulus arvensis), 

 twining round the 

 stems of other plants 

 and strangling them ; 

 leaves cordate-sagit- 

 tate; flowers greenish- 

 white, in erect, slen- 

 der, axillary and ter- 

 minal racemes, bear- 

 ing 4 — 10-flowered 

 clusters ; outer peri- 

 anth-segments bluntly 

 keeled, green with 

 white margins ; fruit 

 rather rough.-— Culti- 

 vated ground; abund- 

 ant— Fl. July— Sep- 

 tember. Annual. 



2. P. dumetbrum 

 (Copse Buckwheat). 

 — A similar but more 



1 • , • polygonum convolvulus {Climbing Persicaria). 



luxuriant species, 



climbing to a height of 4 or 5 feet ; flower-stalks more slender ; outer 

 perianth-segments winged ; nut smooth and shining. — Bushy places 

 in the south of England ; rare. — Fl. July — September. Annual. 4 



** Mostly prostrate plants ; leaves narrow ; stipules silvery, ' 

 torn; flowers axillary, 1 — 3 together ; stamens usually 8; styles 3 ; 

 nut 3- sided 



3. P. aviculdre (Common Knot- grass). — A common weed 

 with branched stem, usually prostrate, but varying greatly in size, 



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