PERSICAK1A TUIBE. 539 



flowers in the lower part of the spike ; the flowers are 

 light flesh-coloured. Fl. June, July. Perennial. 



3. P. aviculdre (Common Knot-grass). Stem branched, 

 prostrate ; leaves narrow, elliptical ; flowers axillary. 

 Waste ground and road sides, abundant. A common 

 weed, with leaves which are furnished with chaffy stipules, 

 and with minute flesh-coloured or greenish-white flowers. 

 It varies greatly in size, and in rich soil often has a ten- 

 dency to grow nearly erect. Fl. all the summer. Annual. 



* Closely allied to P. aviculdre are P. JRoberti, a sea- 

 side plant, with stouter stems, glaucous foliage, and large 

 shining fruit ; and P. maritimum, also a sea-side plant, 

 but very rare, distinguished from the preceding by its 

 large, nerved stipules, and shrubby stem. 



4. P. Fagopyrum (Buck-wheat). Stem erect ; leaves 

 heart-arrow-shaped, acute ; flowers in spreading panicles. 

 A doubtful native, found only near cultivated land, 

 where it is grown principally as food for pheasants. 

 The stems are branched and about a foot high, the 

 flowers light flesh-coloured. El. July, August. Annual. 



5. P. Convolvulus (Climbing Persicaria). Stem twin- 

 ing ; leaves heart-arrow-shaped ; segments of the perianth 

 bluntly keeled ; fruit roughish. Cultivated ground, 

 abundant. A mischievous weed with the habit of the 

 Field Convolvulus, twining round the steins of corn and 

 other plants, and bearing them down by its weight. 

 The flowers are greenish-white, and grow in axillary 

 spikes about 4 together. Fl. July, August. Annual. 



* P. dumetorum (Copse Buck-wheat) is distinguished 

 from the last by its more luxuriant growth, its winged 

 perianth, and shining fruit. It grows in bushy places 

 in the South of England. 



** Styles mostly 2 ; fruit flattened. 



6. P. ampMbium (Amphibious Persicaria). Stem 

 erect, or supported in the water by the floating leaves ; 

 flowers in oblong spikes ; stamens 5 ; leaves oblong, 

 heart-shaped at the base. Ditches and banks of pools, 



