389 
POLYGONACEJE. (BUCKWHEAT FAMILY.) 
13. P. tenue, Michx. (Slender Knot-grass.) Stem low and 
slender, upright, sparingly branched, sharp-angled; leaves sessile , nar- 
roicty linear, very acute; sheaths capillary-fringed ; flowers almost 
sessile, often solitary, greenish-white ; fruit nearly smooth , shining. — 
Dry soil, and rocky hills, New England to Penn, and westward, com¬ 
mon southward. July-Sept. — Plant 6'-12'high. 
* * Flowers solitary from the axils of closely approximated or imbri- 
cated truncate bracts, thus forming many-jointed terminal spikes: 
sheaths cylindrical , naked and entire. 
14- articulsVtum, L. (Jointweed ) Stem upright, pan- 
iculately branched, low (4'-12' high), slender; leaves linear-thread- 
form, deciduous; flowers crowded in slender and spike-like panicled 
racemes, on recurved pedicels twice the length of the joint-like bracts 
(rose-color); fruit smooth and shining. — Sandy soil, Maine to New 
Jersey and southward near the coast, and Oneida Lake and Albany, 
New York. Aug. — Singular for its many-jointed spikes or racemes, 
which are l'-3' long ; the lower bracts tooth-pointed on one side. — 
Not a Polygonella! 
§ 5. TovA.ria, Adans. — Calyx rather herbaceous (greenish), unequal¬ 
ly 4-parted : stamens 5: styles 2, distinct, rigid and persistent on the 
smooth lenticular achenium (cotyledons oblong, accumbcnt) : perenni¬ 
al : flowers loosely disposed in a naked long and slender spike. 
15. P, Virginia num, L. (Wand-spiked Persicaria.) 
Almost smooth ; stem angled, upright (2?-4° high) ; leaves ovate, or 
the upper ovate-lanceolate, taper-pointed, rounded at the base, short- 
petioled, rough-ciliate ; sheaths cylindrical, truncate, hairy and fring¬ 
ed ; flowers 1-2 from each bract, somewhat curved, the styles in 
fruit obliquely bent down, minutely hooked at the tip. — Thickets in 
rich soil, common. Aug. — Leaves 3' - 6' long. Spike 10' - 20' long: 
pedicels scarcely projecting beyond the sheathing bracts. 
§ 6. Helxine, L. — Calyx 5- parted : stamens mostly 8 : styles or cap¬ 
itate stigmas 3, and achenium 3-sided, or, in No. 16, styles 2 and acht- 
nium lenticular: twining or climbing annuals, with heart-shaped or 
arrow-shaped petioled leaves: sheaths semicylindrical. 
* Steins flaccid, not twining, but somewhat climbing or supported ori 
other plants by the reflexed prickles which beset the angles of the stem 
and petioles: divisions of the (pale rose-colored or white) calyx not 
keeled: bracts chaff-like. 
16* P. arifdliuin, L. (Halbert-leaved Tear-thumb.) 
Stem grooved-angled ; leaves halbert-shaped, taper-pointed, long-peti- 
oled ; flowers somewhat racemed (few) ; peduncles glandular-bristly ; 
calyx often 4-parted, closed ; stamens 6; styles 2, very short ; fruit 
lenticular (large). — Low grounds. Aug.— Leaves 2'-S' long; the 
divergent lobes at the base also pointed. 
33* 
