beautifulflowers032840mbp

late 53] POLYGONUM 139
POLYGONAGEAE.
The Buckwheat Family.
From the Greek polys, many, and gony, the knee, alluding to
stem being often enlarged and bent at the joints.)
the
POLYGONUM, Linn.
V. Stipules very small, bipartite.
I. Flowers in terminal clusters. Nut
almost round ... ... ... ... P. islandicum.
II. Flowers in terminal and axillary
clusters. Nuts 3 -angled.
1. Leaves -J in. long
... ... P. delicatulum.
2. Leaves J-f-1 in. long
.
... P. filicanle.
3. Stipules tube-shaped.
I. Stems erect or prostrate.
1. Flowers axillary.
a. Nerves of stipules prominent,
aa. Stems rough.
bb.
i. Two outer sepals awned
on back ... ... ... P. paronychioides.
ii. Two outer sepals not
awned on back (fig. 2)... P. recumbens.
Stems smooth.
i. Perianth cleft $ way down P. cognatwn.
ii. Perianth cleft to near the
base ... ... ... P. aviculare.
b. Nerves of stipules none or very
faint.
aa. Perianth shortly toothed ... P. tubulosum.
bb. Perianth deeply toothed ... P. plebejum.
2. Flowers in terminal racemes.
a. Bracts tube-shaped.
aa. Nuts biconvex,
i. Bracts hairy.
1. Leaves egg-shaped
... P. orientate.