L28 POLVGONACEAE. 



POLYGONACEAE. Buckwheat Family. 



Our herbs or low bushes with simple leaves. Flowers small, regular, mostly 

 perfect, without petals, and rarely solitary. Stamens 4 to 9, slightly perigy- 

 nous. Calyx 5 to 6-cleft or -parted. Ovary superior, 1-celled, 1-ovuled and 

 bearing 2 or 3 styles or stigmas. Fruit an achene, triangular in all of ours 

 except some species of Polygonum and Eriogonum. 



A. Leaves without stipules, opposite, or in no. 5 mostly radical or alternate: flozvers 



borne in an involucre (except no. 2). 

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



opposite, broad 1. Pterostegia. 



Involucre none; calyx involucre-like; leaves linear, in whorls 2. Lastarriaea. 



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. 



B. 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 covering to the achene; flowers mostly 



green 6. Rumex. 



Sepals 5 (or 4), equal and erect in fruit: flowers mostly colored 7. Polygonum. 



1. PTEROSTEGIA F. & M. 



Very slender and weak annuals with dichotomous branches and opposite 

 leaves. Flowers solitary and sessile, longer than the subtending involucre. 

 Involucres terminal and nearly sessile in the forks, consisting of a single bract, 

 rounded and more or less 2-lobed, dentate on the margin, in fruit enlarged, 

 scarious and reticulated, loosely enclosing the achene and with 2 sac-like pro- 

 tuberances on the back. Calyx 6 or 5-parted; stamens as many or fewer than 

 the lobes. (Greek pteron, a wing, and stegia, a covering, in reference to the 

 involucre.) 



1. P. drymarioides F. & M. Stems commonly several from the base, usu- 

 ally with a branch at each node, diffuse or straggling, a few in. to 1 ft. long; 

 leaves roundish or broader than long and notched once or twice at apex or 

 even cleft, or distinctly fan-shaped or obcordate, 3 to 6 lines broad, nar- 

 rowed at base to a slender but mostly short petiole; flower reddish, less than 

 I line long; perianth-segments oblong-lanceolate. 



Opes woods under oaks or in the shade of rock outcroppings: Coast Ranges 

 and Sierra Nevada to Southern California. April-May. 



2. LASTARRIAEA Remy. 



Small, fragile annual, diffusely branched from the base. Leaves linear, 

 in cauline whorls and in a radical tuft which disappears early. Floral bracts 

 in whorls, with hooked ;i\vns. [nvolucre none. Flowers sessile in the forks 

 and terminal. Calyx simulating an involucre, tubular, 5 to 6-cleft to the middle, 

 the teeth with recurved, hooked awns. Stamens •">, inserted on the throat, with 

 n small membranous tooth on each side of the filaments, (.lose Victorino 

 Lastarria, 1817-1888, Chilean publicist and writer on the constitutional history 

 of Chile.) 



1. L. chilensis Remy. Branches - to 8 in. long; floral bracts concealing 

 the flowers; perianth 1 to iy> lines long. 



[introduced from Chile. Antioch; southward to Kern and Monterey cos. 



.- 1 1 1 < I Southern California. May-dune. 



