576 POLYGONAOE.E ptekostegia 



POLYGONDM 



forming irregular whorla at the lower joints: involucres in the lower axils 

 few, without scarious margins, the upper in condensed capitate heads, with 

 equal broadly expander! 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 revolut^, densely 

 tomentose beneath ; lower cauline similar, but smaller and uncinately 

 awned, passiilg above into opposite uncinate-tipped bracts : involucres 

 clustered on the upper branches, narrow, inconspicuously costate, unequ- 

 ally 5-lobed, one S-4 times as long as the others, all uncinate tipped: 

 flowers solitary, slender -pedicelled, included or partly exserted, the seg- 

 ments 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 smalt flowers 

 solitary in foliaceous sessile involucres in the forks of the bran- 

 ches. Involucre of a single bract, subtending arid shorter than 

 the sessile flower, rounded and more or less 24obed, at length be- 

 coming enlarged, scarious and reticulated, loosely enveloping the 

 achene, and gibbously 2-saccate on the back. Calyx 5-6-parted, 

 the segmeiits 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 petioled, 2-tJ lines broad, fan-shaped) 2- 

 lobed, the lobes crenately toothed or again lobed; upper leaves obovate to 

 spatulate, entire or toothed : bracita similar, aline long: involucres very 

 small, becoming 1-1)^ lines long in fruit, somewhat 2-lobed, the margins 

 toothed or laciniate : flowers yellowish the segments oblong-lanceolate. 

 Hillsides and dry places,' from the Columbia river to Lower California. 



Tribe 2 Polygonacex' Endl. Gen. SOI. Herbs with alternate 

 leaves and scarious sheathing stipules. Flowers without involucre. 

 S-6-parted. Stamens mostly ^-8. Styles S or 3. Juice usually 

 pungent, acrid or acid. 



5 POLYGONUM L. Sp. 3S9. 



Annual or perennial plants with jointed stems, alternate leaves 

 scarious sheathing stipules, called ocreae, 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, 

 or 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 orrfxceeding the persistent calyx, Embryo near the 



