POLYGON ACE.E. 191 



slender, erect, pale rose-coloured. Sepals glandular-dotted. 

 Stamens 8. Achene 3-angled, shining. Muddy soil or 

 shallow water. 



13. P. Hydrop'iper, L. (COMMON SMARTWEED or 'WATER- 

 PEPPER.) Sheaths and leaves as in the last, the leaves, how- 

 ever, larger. Spikes slender, nodding, greenish. Sepals 

 glandular-dotted. Stamens 6. Achene dull. Wet places. 



14. P. Virginia'num, L. Calyx greenish, unequally 4- 

 parted. Stamens 5. Styles 2, persistent on the flat achene. 

 Flowers in long and slender naked spikes. Stem upright, 

 nearly smooth. Leaves ovate or ovate-lanceolate, taper- 

 pointed, rough-ciliate. Sheaths hairy and fringed. Thick- 

 ets, in rich soil. 



-i- *- Leaves heart-shaped or sagittate. Sheaths much longer on one 

 side than on the other. 



15. P. arifo'lium, L., (HALBERD-LEAVED TEAR-THUMB) 

 with grooved stem, halberd-shaped long-petioled leaves, 

 flowers in short loose racemes, 6 stamens, and a flattish 

 achene, is not uncommon on the Lower St. Lawrence ; rare 

 in Ontario. 



16. P. sagitta'tum, L. (ARROW-LEAVED TEAR-THUMB.) 

 Stem 4-angled, the angles beset with reflexed minute prickles, 

 by which the plant is enabled to climb. Leaves arrow- 

 shaped. Stamens 8. Achenes 3-angled. Common in low 

 grounds, especially beaver-meadows. 



17. P. Convol'VUlus, L. (BLACK BINDWEED.) Stem twin- 

 ing, not prickly but roughish ; the joints naked. Flowers 

 in loose panicled racemes, 3 of the calyx-lobes rigid in fruit. 

 Leaves heart-shaped and partly halberd-shaped. Not climb- 

 ing so high as the next. Cultivated grounds and waste 

 places. 



18. P. dumeto'rum, L., var. scandens, Gray. (CLIMB- 

 ING FALSE BUCKWHEAT.) Stem twining high, smooth ; sheaths 

 naked, 3 of the calyx-lobes winged in fruit. Moist thickets. 



19. P. eilino'de, Michx. Stem twining,, minutely downy. 

 Sheaths fringed at the base with reflexed bristles. Sandy pine 

 woods and rocky hills. 



