346 POLYGON ACEJE. [Polygonum. 



and rose. Fruit black, punctulate. — Distrib. N. temp, hemisphere. — 

 Very acrid, and a reputed diuretic. 



8. P. minus, Huds. ; animal, racemes very slender straight, sepals 

 usually 5 with minute glands at the base only, styles 2-3 united half way, 

 fruit smooth plano-convex or 3-gonous as long as the sepals. 



Marshy places, local from Perth and Renfrew southd. ; Ireland, rare ; fl. Aug.- 

 Sept. — Stem 6-24 in., usually very slender, much branched, erect or 

 ascending. Leaves 1-3 in., narrow-lanceolate, ciliolate, eglandular ; stipules 

 not inflated, short, cilia te. Racemes 1-3 in., solitary or panicled, usually on 

 slender peduncles. Sepals xn~h m -> very small. Fruit pitchy-black, shining, 

 acute. — Distrib. Europe, N. and W. Asia, India. 



Section 3. Avicula'ria, Meissn. Annual or biennial. Leaves narrow ; 

 stipules silvery, at length lacerate. Flowers axillary, solitary or fascicled ; 

 pedicels jointed at the top. Stamens usually 8. Styles usually 3. Fruit 

 3-quetrous ; embryo lateral, cotyledons thin flat. 



9. P. avicula're, L. ; prostrate, nerves of leaves obscure beneath, 

 stipules small, nerves few simple. Knotgrass. 



Fields and waste places, N. to Shetland; ascends to 1,800 ft. in Northumbd. ; 

 Ireland; Channel Islands; fl. May-Oct. — Annual, glabrous, eglandular, 

 branched from the base ; branches |-3 ft., straggling, grooved, angular 

 above, leafing and flowering throughout. Leaves ^-1^ in., xn~2 m « broad, 

 sessile or shortly petioled, linear-lanceolate or -oblong, narrowed at both 

 ends, rarely broadly elliptic or almost filiform, acute or obtuse, margins 

 flat or recurved ; stipules §-| in., white, red at the base, lacerate. Flowers 

 tV"S in., white, pink, crimson, or green, clustered in the axils, homogamous. 

 Fruit brown, minutely striate and punctate. — Distrib. Europe (Arctic), 

 N. and W. Asia ; iutrod. in N. America. 



P. AvrcuLA'RE proper ; leaves rather thin, fruit dull included. — Vak. P. lit- 

 tora'le, Link ; leaves rather fleshy, fruit more shining, tip exserted. Littoral. 

 The passage to P. inarit'imum. — Var. agresti'num, Jord., is the common 

 robust field form, arenas'trum, Boreau, a sand-loving prostrate one ; micro- 

 sper'mum, Jord., a small fruited one ; and ruriva'gum, Jord., a wayside one 

 with narrow very acute leaves. 



Sub-sp. P. Rober'ti, Loisel ; fruit longer than the sepals. P. Rai'i, Bab. 

 in part.— Sandy shores. 



10. P. marit'imum, L. ; prostrate, nerves of the leaves reticulate 

 beneath, of the stipules few or many, sepals shorter than the fruit. 



Sea-shores, Hants, Devon, Cornwall ; Channel Islands; fl. July-Sept. — Similar 

 to P. avicula're, but perennial, much stouter, more rigid and woody, darker 

 when dry ; leaves thicker, often glaucous beneath ; stipules larger more 

 scarious and nerved ; flowers and fruit much larger. — Distrib. France, 

 Spain, Mediterranean, W. Asia, N. America. 



Section 4. Tinia'ria, Meissn. Annual (the British species), usually 

 twining. Leaves cordate or sagittate ; stipules truncate, mouth entire. 



