Polygonum.] POLYGONJCEuE. 347 



Flowers in racemose clusters. Sepals enlarging. Stamens 8. Styles 3, 

 united. Fruit 3-quetrous ; embryo lateral, cotyledons narrow flat. 



11. P. Convolvulus, L. ; leaves cordate-sagittate, 3 outer sepals 

 obtusely keeled rarely winged, pedicels short jointed above the middle, 

 fruit dull striate granulate. Black Bindweed. 



Fields and waste places, from Caithness southd. ; ascends to 1,350 ft. in Derby; 

 Ireland; Channel Islands; fl. July-Sept.— Root fibrous. Stem 1-4 ft., an- 

 gular, twining climbing or prostrate, slender, angles puberulous. Leaves 

 1^-4 in., petiole shorter, slender, gradually acuminate, lateral angles obtuse 

 or acute, eglandular, puberulous beneath ; stipules short. Racemes erect, 

 terminal and axillary, slender, pedicels recurved. Sepals 5, obtuse, green, 

 margins white, 3 outer rough at the back, at length £ in., and covering the 

 fruit. — Distkib. N. temp, and Arctic regions ; introd. in America. 



P. Convol'vulus proper ; clusters 4-6-fld., outer sepals obtusely keeled in fruit. 

 — Var. pseudo-dumeto'rum, Wats. ; clusters 5-10-fld., outer sepals broadly 

 winged in fruit. 



12. P. dumeto'rum, L. ; leaves cordate-sagittate, 3 outer sepals with 

 broad membranous wings, pedicels very slender jointed below the middle, 

 fruit smooth highly polished. 



Hedges and thickets, Monmouth and Essex to Kent and Devon, rare, soon 

 disappearing ; fl. July-Aug. — Habit of P. Convol'vulus, but pedicels capil- 

 lary (often ^ in.) and seed polished. The stems are described as terete, but 

 I find them as much angled as in P. Convol'vulus. — Distrib. Europe, N. 

 and W. Asia, N.W. India. 



2. ru'mex, L. Dock. 



Biennial or perennial herbs. Rootstock stout, tapering into the root. 

 Stems usually grooved. Leaves alternate ; stipules tubular. Flowers 1-2- 

 sexual, in panicled or racemed whorls, anemophilous. Sepals 6, 3 inner 

 enlarging. Stamens 6 ; anthers basifixed. Ovary 3-quetrous ; styles 3, 

 filiform, stigmas penicillate. Fruit 3-quetrous. Embryo lateral. — 

 Distrib. All temp, climates ; species about 100. — Etym. The old Latin 

 name. 



Hybrids are common in this genus ; those most known to cross are said to be 



pulcher, crispus, and conglomerates. 



Section 1. Lap'athum, Meissn. Leaves not hastate. Flowers 2-sexual 

 (monoecious in R. alpinus). Inner sepals coriaceous in fruit. 



* Inner fruiting sepals usually strongly toothed. 



1. R, obtusifo'lius, L. ; radical leaves oblong-ovate cordate obtuse, 



panicle leafy below, inner fruiting sepals elongate triangular obtuse usually 



strongly toothed at the base, upper or all with an ovoid tubercle. 



Fields, waste grounds, N. to Shetland; ascends to 1,600 ft. in N. England; 



Ireland ; Channel Islands ; fl. Aug.-Sept.— Perennial, 2-3 ft., stem stout and 



leaves beneath puberulous. Leaves 6-12 in., subacute or obtuse, margin 



crenulate waved, upper oblong-lanceolate ; petiole rather slender. Panicle 



narrow ; pedicels ^-twice as long as the reticulate fruiting sepals, \-\ in. ; 



