BUCKWHEAT KAMI I A". 



:.: 



ii m. 



mum. 



36. P. 



Plants erect or ascending, rather stout. 

 Achene invested by the calyx. 



Leaves oval, oblong or obovate, persistent 

 Leaves narrowly lanceolate or linear -ublong, persistent 

 Leaves oblong-lanceolate or narrowly oblong. 1'iig.ifiniis. 

 Achene much exserted beyond the calyx. 

 Plants strictly erect and very slender. 



Leaves with a lateral impression on either side of the midvein. fruiting pedicel* *t. 



Leaves without lateral impressions; fruiting pi-dice Is slender, dcflexid 3.'. / 



4. Flowers in axillary and terminal clusters, racemes or panicled racemes; stems mostly twining. 

 Stems twining; herbaceous vine--. 



Outer segments of the calyx unchanged, or keeled in fruit. 



Achene granular and dull; ocreae tint bristly. 31. /> Cottfolitiliii. 



Achene smooth and shining; ocreae bristly. 

 Outer segments of the calyx conspicuously winged in fruit. 

 Calyx-wings not incised. 



Fruiting calyx s"-6" long, the wings crisped. 



Fruiting calyx 3" -4" long, the wings rather flat. ,, 



Calyx-wings incised. ,/, 



Stems stout, erect, tall; outer calyx-segments winged in fruit. 36. /' 



5. Flowers in capitate clusters or racemes ; stem climbing by recurved prickles. - 

 Leaves sagittate; achene 3-angled. // tat inn 



Leaves halberd-shaped ; achene lenticular. 38. P. ari/olitim, 



i. Polygonum viviparum L. Alpine 

 Histort. (Fig. iv 



Polygonum riripatnm I.. Sp. PI. 360. 1753. 



Perennial by a conn-like rootstock, mostly gla- 

 brous and somewhat glaucous; stems solitary or 

 clustered, erect, simple, slender, s'-io' tall. Basal 

 leaves oblong or lanceolate, i'-8' long, rather acute 

 at the apex, cordate or subcordatc at the base, long- 

 petioled; stem leaves narrowly lanceolate or linear, 

 i '-3' long, the lower petioled, the upper sessile, 

 their margins often revolute; ocreae long, clasping 

 below, open above; raceme solitary, terminal, nar- 

 row, rather dense, bearing a number of dark colored 

 bulblets about its base; calyx 5- parted, pale rose- 

 color or white; stamens S, exserted; style 3-parted, 

 its branches exserted; achene oblong, 3-angled. 



Greenland and Labrador to Alaska, south to the high 

 summits of the mountains of New England. ami in the 

 Rocky Mountains to Colorado. Also in arctic and 

 alpine Europe and Asia. June-Aug. 



2. Polygonum amphibium L,. 



Polygonum amphibium- L. Sp. PI. 361. 1753. 



Aquatic, perennial, glabrous when mature; 

 stem floating or submersed, simple or spar- 

 ingly branched, 4-2o long. Leaves oblong, 

 elliptic or elliptic-lanceolate, i l /2'-\' long, peti- 

 oled, obtuse or subacute at the apex, slightly 

 inequilateral, rounded or narrowed at the 

 base, sometimes ciliate; ocreae cylindric, those 

 of the branches often longer than the inter- 

 nodes, their limbs sometimes spreading, usu- 

 ally glabrous; raceme terminal, usually soli- 

 tary, Yi'-i' long, dense, erect, oblong or ovoid; 

 calyx rose-color, 5-parted; stamens 5, exserted; 

 style 2-cleft, exserted; achene orbicular ob- 

 long, lenticular, \ l /t" long, biconvex, black, 

 smooth and shining, or granular. 



In ponds and lakes, Quebec to Alaska, south to 

 northern New Jersey, Kentucky, > Colorado and 

 California. Ascends to 2000 ft. in the Adiron- 

 dacks.j t Also in Europe. July-Aug. 



Water Persicaria. (Fig. 1319.) 



