120 Potygonaceae 



6-parted, the 3 outer sepals unchanged in fruit, the 3 inner 

 ones (wings) usually bearing a grain-like callosity on 

 the back, larger and enclosing the achene. Stamens 

 6 ; filaments short, glabrous ; anthers oblong. Style 

 3-parted ; stigmas peltate, tufted. Achenes 3-angled. 



* Flowers dioecious; leaves hastate. 



1. B. Acetosella L. Perennial by slender running rootstocks, 

 slender erect or nearly so, simple or branched, 2-4 dm. high, gla- 

 brous; leaves narrowly hastate, petioled, the uppermost leaves 

 somewhat entire; panicle narrow, naked, becoming reddish; 

 calyx green,! mm. long; stamens exserted; achene granular, 

 exceeding the persistent calyx. 



In moist grassy places about Los Angeles. Native of Europe. 



** Flowers perfect; leaves not hastate. 



*- Inner calyx-lobes with slender awned teeth. 



2. B. pulcherL. Stems erect, 5-8 dm. high, with rigid di- 

 varicately spreading branches ; leaves scabrous beneath, the basal 

 oblong or lanceolate, acute, cordate or obtuse at base ; flow r ers on 

 short stout rigid pedicels; wings ovate, 2-3 mm. long, with 4-6 

 rigidly awned teeth on each side. 



Sparingly introduced, Inglewood. Native of Europe. 



3. B. persicarioides L. Annual, pubescent, pale green ; stem 

 erect, simple or branched, 2-6 dm. high, sometimes spreading, 

 very leafy; leaves lanceolate or oblong, 2 dm. long or usually 

 less, narrowed at the base or cordate, acute at the apex, the 

 margins undulate and somewhat crisped; panicle simple or 

 branched; racemes erect, leafy bracted; whorls dense, usually 

 rather distant ; pedicels equaling or somewhat exceeding the 

 inner calyx-lobes, jointed at the base; inner calyx-lobes oblong, 

 2 mm. long, with 1-3 bristles on each margin, each bearing an 

 ovoid or oblong grain; achene about 1.5 mm. long, pointed, 

 reddish. 



Frequent in moist places, especially along the margins of ponds. Native 

 of Europe. 



*- Inner calyx-lobes with entire or dentate or erose margins, herbage 

 glabrous. 



4. B. salicifolius Weinm. Glabrous and somewhat glaucous ; 

 stems ascending or spreading, simple or branched, grooved, flexu- 



