Ol'd. 2.] OCTANDRIA TRIGYNIA. 85 



OCTANDRIA TRIGYNIA. 



220. POLYGONUM. Persicaria, Bistort, Knot-grass, & Buckwheat. 



* Styles 2. 



1. P. amphibium, 7. 436. (Amphibious P.) Stamens five. Styles 



two, united half way up. Spike ovate. 

 Ponds and ditches. If. 7, 8. Creeping, floating. L. stalked. Fl. 

 crimson. 



2. P. Persicaria, 11. 756. (Spotted P.) Stamens six. Styles two, 



united half way up. Clusters dense, ovate-oblong, erect, on 

 smooth stalks. Stipulas fringed. 

 Ponds and marshes. ©. 7, 8. Stem erect. L. marked with a black 

 lunate spot. 



3. P. lapathifolium, 20. 1382. (Pale-flowered P.) Stamens six. 



Styles two, distinct. Flower-stalks rough. Stipulas beardless. 

 Seeds concave at each side. 

 Dunghills, & cult. gr. 0.7,8. Spreading. L. with glandular dots. 



4. P. Hydropiper, 14. 989. (Biting P.) Stamens six. Styles two, 



united half way up. Leaves lanceolate, wavy, without spots. 

 Clusters lax, interrupted, drooping. Stem erect. 

 Ditches and watery pi. . 9. Smooth, slender. Fl. with glandu- 

 lar dots. 



5. P. minus, 15. 1043. (Small creeping P.) Stamens six. Styles 



two, combined. Leaves linear-lanceolate, flat. Clusters lax, 

 slender, nearly upright. Stem trailing at the base. 

 Wet gravelly commons. ©. 9. Smaller. Fl. without spots. 



** Styles three. 



6. P. Bistorta, 8. 509. (Bistort, or Snake-weed.) Stem simple, 



with a single, spiked cluster of flowers. Leaves ovate, wavy, 

 running down into the footstalks. 

 Mead, and past. If. 6. About 18 in. Spike thick, blunt. Stam. 

 occasionally but 6. 



7. P. viviparum, 10. 669. (Alpine B.) Stem simple, with a single, 



spiked cluster of flowers. Leaves lanceolate, revolute, with 

 numerous prominent marginal veins. 

 Mountain past. If . 6, 7. 3 — 6 in. Spike linear. Fl. vivip. 



8. F.aviculdre, 18. 1252. (Knot-grass.) Flowers nearly sessile, 1 — 3 



in the axils. Seeds incrusted, striated with minute, raised 

 points. Leaves elliptic-lanceolate. Stipulas shorter than the 

 internodes ; their ribs remote. Stems herbaceous, usually pro- 

 cumbent. 

 Waste gr. 4 — 10. Fl. small, often tipped with red. Leaves 

 generally minutely crisped at the edge. 

 *8. P. acetosum, Bieb. Fl. T. Cauc. (Acid sea-side K.) Flowers on 

 short stalks, 1 — 3 in the axils. Seeds protruded, quite even, 

 glossy. Leaves elliptic-lanceolate, glaucous. Stipules much 

 shorter than the internodes j their ribs remote. Stems herba- 

 ceous, prostrate. 



