576 ‘POLYGONACEE PTEROSTEGIA 
POLYGONUM 
forming irregular whorls at the lower joints: involucres in the lower axils 
few, without scarious margins, the upper in condensed capitate heads, with 
equal broadly expanded scarious winged divisions, reflexed, rotate and 
tipped with a slender uncinate awn, the tube ribbed and protuberant below 
flowers 2-3, one with long pedicel partly exserted, the others undeveloped : 
flowers short tubular, hairy outside, the segments oblong, equal: stamens. 
at the base. On rocky foothills southern Oregon to California. 
C. Watsoni T. & G. Proc. Am. Acad. viii, 199. Canescently pubescent 
-throughout: stem erect or ascending, 1-4 inches long, branching from the 
base: radical leaves narrowly oblanceolate to spatulate, 6-10 lines long, 
narrowed to a petiole with dilated base, the margins revolute, densely 
tomentose beneath; lower cauline similar, but smaller and uncinately 
awned, passing above into opposite uncinate-tipped bracts: involucres 
clustered on the upper branches, narrow, inconspicuously costate, unequ- 
ally 5-lobed, one 3-4 times as long as the others, all uncinate tipped: 
flowers solitary, slender-pedicelled, included or partly exserted, the seg- 
nents oblong, acute, pubescent outside: stamens inserted on the throat of 
the calyx: achenes oblong-triangular. On desert districts, southeastern 
Oregon to Nevada and California. 
4 PTEROSTEGIA-F. & M. Ind. Sem. Petr. ii, 48. 
Very slender and weak diffusely and dichotomously branched 
annuals with opposite entire or 2-lobed leaves and small flowers 
solitary in foliaceous sessile involucres in the forks of the bran- 
ches. Involucre of a single bract, subtending and shorter than 
the sessile flower, rounded and more or less 2-lobed, at length be- 
coming enlarged, scarious and reticulated, loosely enveloping the 
achene, and gibbously 2-saccate on the back. Calyx 5—6-parted, 
the segments equal. Stamens inserted at the base of the seg- 
ments, as many or fewer. Achene triangular, glabrous. Cotyle- 
dons rounded, accumbent upon the radicle. | 
P. drymarioides F. & M. 1. c. Sparingly hirsute: stems decumbent. 
often 1-2 feet long: lower leaves Liege 2-6 lines broad, fan-shaped, 2- 
lobed, the lobes crenately toothed or again lobed; upper leaves obovate to 
spatulate, entire or toothed: bracts similar, a line long: involucres very 
small, becoming 1-14 lines long in fruit, somewhat 2-lobed, the margins 
toothed or laciniate: flowers yellowish the segments: oblong-lanceolate. 
Hillsides and dry places, from the Colux:bia river to Lower California. 
Tribe 2 Polygonacee Endl. Gen. 301. Herbs with alternate 
leaves and scarious sheathing stipules. Flowers without involucre. 
3-6-parted. Stamens mostly 4-8. Styles 2 or 3. Juice usually 
pungent, acrid or acid. 
5 POLYGONUM L. Sp. 389. 
Annual or perennial plants with jointed stems, alternate leaves 
scarious sheathing stipules, called ocree, and small normally 
perfect flowers in spikes, racemes or panicles. Calyx 4-6-parted, 
or 4-6-cleft, the outer sepals or segments somewhat longer than 
the inner. Stamens 3-9, included or exserted ; filaments filiform, 
er dilated at base, glabrous. Style 2-3-cleft or 2-3-parted, with 
capitate stigmas. Achenes lenticular or 3-angled, rarely 4-angled, 
invested by or exceeding the persistent calyx. _Embryo near the 
