148 



POLYGOXA( ILK. 



or obtuse, 2 to 5 or 6 lines long; flowers in somewhat dense clusters, 

 these disposed in mostly geminate (or somewhat paniculately branched) 

 axillary racemes 3£ in. long or less, the pistillate inflorescences some- 

 what shorter and in the axils above the staminate; stamens twice as 

 long as the calyx, their filaments dilated at base; sepals of pistillate 

 flower enclosing but scarcely exceeding the achene. 



Yery common along streams in the valleys throughout the state. 

 Aug. -Sept. 



2. HESPEROCNIDE Torr. 

 Annual herbs similar to the last genus, but the pistillate calyx con- 

 sisting of a membranous flattened oblong-ovate sac with a minutely 

 2 to 4-toothed orifice. (Greek hespera, west or western, and knide, 

 a nettle.) 



1. H. tenella Torr. Slender, erect or straggling, 1 or 2 ft. high; 

 stems and petioles bristly with scattered hairs, the blades very 

 sparsely hispid; leaves thin, ovate, serrately incised, J to 1^ in. long 

 on slender petioles; flowers densely glomerate in the axils, the clusters 

 shorter than the petioles; calyx thin, hispid with hooked hairs, in 

 fruit ^ to less than 1 line long; achene with minutely roughened 

 pericarp. 



Napa Co.; Bushy Knob (southeast of Mt. Diablo); and southward. 



Parietakia debilis Forster is unarmed and has alternate entire 

 leaves without stipules and a tubular pistillate calyx.— Santa Barbara 

 southward. 



21. POLYGON ACE^E. Buckwheat Family. 



Ours herbs or suffrutescent plants with alternate or opposite simple 

 leaves and small regular apetalous mostly perfect flowers. Stamens 

 4 to 9, slightly perigynous. Calyx 3 to 6-cleft. Ovary ] -celled, 

 bearing 2 or 3 styles or stigmas and a single erect orthotropous ovule. 

 Fruit an achene, triangular in all ours except some species of 

 Polygonum and Eriogonum. 



Leaves without stipules. 

 Involucre bract-like, 1-flowered, enlarged in fruit, 2-lobed, 2-saccate on the 



back; leaves opposite, broad 1. Pterostegia. 



Involucre noue; calyx involucre-like; leaves linear, in whorls 



2. Last a rr] i a . 



Involucre tubular, campanulate or turbinate; leaves alternate or in whorls 

 or radical. 



Involucre one-flowered; teeth of the involucre 3 to 6, cuspidate or awned, 



often hooked 3. Chorizanthe. 



Involucre two to many-flowered and 

 Deeply 4 (3 to 5) -cleft, the lobes bearing bristles or awns, or awnless. . . . 



4. Oxytheca. 



Four to 8-toothed, the teeth blunt or at least not bristly . .5. Eriogonum. 

 Leaves with sheathing stipules, alternate; flowers without involucre. 

 Sepals 6, the outer 3 reflexed in fruit, the inner 3 erect and enlarging; calyx 

 closing about the fruit and persisting as a hardened coveiing to the 



achene; flowers mostly green 6. Rumex. 



Sepals 5 (or 4), equal and erect in fruit; flowers mostly colored 



7. Polygonum. 



