160 POLYGON ACE^. 



3. P. aviculare L. Wire Gkass. Yakd Gkass. Glabrous 

 and green; stems wiry, minutely striate, prostrate, often several ft. 

 long, 'flowering from tlie base; leaves oblong, acute, 3 to 6 lines long; 

 flowers on very sbort pedicels, 2 lines broad when expanded; calyx 

 cleft into oblong lobes which are white with a green center; stamens 

 8, the 3 inner with dilated bases; styles 3, very short; achene ovoid, 

 dark brown, minutely granular. 



Naturalized: common in hard, especially beaten soils, and some- 

 - times in cultivated lands; flowering through the summer into early 

 winter. 



4. P. spergulariaeforme Meisn. Annual, much branched and 

 somewhat diffuse, or sparingly branched and more strictly erect, 4 to 

 13 in. high; sheaths with a short mostly scarious base and lacerate 

 summit; leaves linear or oblanceolate, at least narrow, 1-nerved, 

 acute, 6 to 13 lines long; spikes 4 in. long or less, very slender, the 

 flowers much scattered below, crowded above; calyx rose-color or 

 white; stamens 8, included, the filaments hardly dilated at base; 

 style as long as the ovary, 3-parted. — (P. coarctatum Dougl.) 



Dry hills. Petrified Forest, Sonoma Co., ace. to Greene; lower 

 slopes of Mt. St. Helena on the Middleton grade, Davy; and north- 

 ward to the Mt. Shasta Eegion. Oct. 



5. P. Californicum Meisn. Annual, 3 to 7 in. high; diffusely 

 branched just above the base, the stems slender and wiry, the ulti- 

 mate branches elongated and floriferous; herbage glabrous, but the 

 brownish stems striate and minutely scabrous; leaves linear to filiform, 

 cuspidate, 3 to 6 lines long, not jointed to the sheathing stipules which 

 are deeply lacerate-fringed'and imbricated on the upper portion of the 

 very slender and elongated spikes; bracts subulate, 1 or 2 lines long; 

 flowers solitary and sessile in each axil; sepals white with rose-colored 

 midvein; achene narrowly lanceolate, slightly exserted; styles slightly 

 divergent. 



Dry hills from Napa Valley and Lake Co. to northern California. 



6. P. Parryi Greene. Dwarf compact annual, commonly branch- 

 ing from base, 1 to 2 in. high; stems rigid and brittle, bearing flowers 

 even to the base; leaves narrowly linear, acute, cuspidate, 1 to 2 lines 

 long; stipules so extremely lacerate as to appear cottony, and often 

 hiding the flowers; flowers solitary and sessile in the axils, the bract 

 broad, laciniate to the middle; stamens included; style 3-parted; 

 achene triangular. 



Sierra Nevada; Coast Eanges, Howell Mountain, ace. to Brandegee, 

 and(?) headwaters of the Eel in Lake Co., Jepson. 



7. P. amphibium L. Watek Persicaeia. Aquatic glabrous 

 perennial with stout stems not branching above the rooting base; 

 leaves floating, elliptical to oblong or oblong-lanceolate, truncate or 

 rounded at base, 2 to 5 in. long on petioles nearly 1 to 2J in. long; 

 sheaths leaf-bearing at about the middle; spike terminal, dense, ovate 

 or oblong, J to 1 in. long, on a commonly short peduncle; calyx 

 bright rose-color, IJ to 3 lines long, the 5 stamens and 2-cleft style 

 exserted; achene lenticular, smooth. 



