204 POLYGONACEAE 
white or greenish-white or rosy, resembling petals, stamens 8; ovary 
1 celled, with a 3-parted style and a stellate stigma. 
1. F. esculentum, Moench. Buckwueat. (fF. Fagopyrum, Karst.) 
Flowers in dense clusters, terminal to the branches of the loose inflores- 
cence. Seed much longer than the perianth, its borders not winged. 
2. F. tartaricum, (L.) Gaertn. Tarrary BucKWHEAT. Leaves simi- 
lar to-No. 1, but broader and more arrow-shaped. Flowers smaller. 
Seed winged, the borders of the wings wavy or lobed. 
3. POLYGONUM, L. 
This family includes several somewhat distinct groups of plants, all 
of which are, in our region, herbs, erect, prostrate or twining. The 
flowers generally include both stamens and pistils and the corolla is 
wanting. The divisions of the calyx, generally 5, which are nearly equal, 
are often colored or white, producing the apparent effect of a corolla. 
Stamens vary from 5 to 8. Fruit a dry hard grain, enclosed in some 
species by the calyx as a seed hull, while in other cases it projects above 
the hull, the seed being partly uncovered. The ocrea or collaret at the 
nodes mentioned as characteristic of the Order Polygonales, is in this 
genus peculiarly conspicuous. 
1st, GRouP.—THE PERSICARIAE 
Erect or prostrate herbs, not twining. Flowers in terminal, elongated clusters. 
1. Flowers surrounding the axis stem in dense, crowded clusters 
Flower clusters single. 
Plant found on mountain summits . . .. . P. viviparum 
Flower clusters generally one, sometimes two. " Aquatic plants. 
Plants smooth. . Leaves elliptic . . . P. amphibium 
Leaves egg-shaped, but with long tapering apex P. Muhlenbergit 
Plant distinctly hairy, generally aquatic . . . . P. Hartwrightiu 
Flower clusters several. 
Herbs, generally less than 3 ft. high. 
Clusters) drooping 3. . © «© « « » «» |, « aulapathpouue 
Clusters erect. 
Plant? hairy! 5) cs os Min.) fey) wy el eo lee OP Medea train emmnNOer Teno 
Plant not hairy. 
Collaret ponepicony fined oe . P.. persicaria 
Collaret not fringed 4 NERS Te pennsylvanicum 
Herb: 3° to. %8 feet high’ (5) 6. ter cu 6, aces is) ek poe neuen Petts Era 
2. Flowers arranged on the long axis stem in loose interrupted series 
THE Water PEPPERS 
Collaret long, hairy and fringed with long bristles. oa es lance-shaped 
Pe ah ore, nae Hob asta fo eee hydropiperoides 
Collaret long, not hairy, fringed with short bristles. 
Stamiens:4t0)'6) d= Ss jie hem re? Lie ile, eae: EPAPER) Sot) eon ein eae 
Stamens 8 i. See cw. os) a 
Collaret hairy and fringed, leaves broad eee: ‘shaped, 
Apex of leaves tapering . . - «© « « « P. virginianum 
Apex of Jeaves blunt © « s « (eu sceB se © 6 we iu) CreeCneR 
2p. GRouP 
Prostrate, or, less frequently, erect herbs with flowers all in the axils of the leaves. 
THE KNOTGRASSES 
Stem leafy to the end; plant prostrate. 
Leaves as long as, or usually longer than, the internodes. 
Leaves rolled!) at) themamargins i.) «stesso P. maritimum 
Leaves not rolled at margins . 0 6 «2 PL prone 
Internodes as long as or longer than the leaves _ Pere ee. i 
Piant erect; leaves’ broad). < %. >. So. eR qe lO te) ee eee 
