BUCKWHEAT FAMILY 8l 



the stem. Flowers small, on jointed pedicels; calyx of 4 to 6 

 nearly distinct petal-like erect segments. Stamens 4 to 9. 

 Styles 2 or 3. Fruit a dry akene, either 3-angled or some- 

 what flattened. 



a. Flowers in a loose panicle; leaves 1 in. or more 



wide 1. P. polymorphism. 



b. Flowers in dense oblong leafless racemes; leaves 



narrower. 



Stems with few leaves; flowers white 2. P. bistortoides. 



Stems leafy; flowers rose-color or pink. 



Raceme solitary; leaf-sheaths not bristly 3. P.amphibium. 



Racemes several; leaf-sheaths bristly-fringed 4. P. persicaria. 



c. Flowers in the leaf-axils. 



Twining herb with heart-shaped leaves 13. P. convolvulus. 



Prostrate woody perennial S. P. shastense. 



Slender glabrous annuals with narrow leaves. 



Plants prostrate 6. P. aviculare. 



Plants erect. 



Leaves obovate; stems reddish, leafy 7. P. minimum. 



Leaves narrower. 



Stems 6 to 24 in. high. f\ 



Flowers erect. 



Leaves merely acute 8. P. ramosissimum. 



Leaves with fine tips 9. P. tenue. 



Flowers pendent 10. P. douglasii. 



Stems 4 in. or less high 



Stems much branched 11. P. kelloggii. 



Stems simple below 12. P. imbricatum. 



1. P. polymdrphum L. Stems stout, erect, 2 to 7 ft. high, 

 perennial. Leaves ovate or lanceolate, acute, 3 to 6 in. long, 

 1 to 2 J /4 in. wide, narrowed or rounded to a winged petiole 

 y 2 to 1 in. long. Flowers greenish white or rose-color, small 

 but numerous in a much branched bracted terminal panicle 

 often 1 or 2 ft. long. (P. phytolaccaefolium Meisn.) — In wet 

 soil along creek banks and the margins of lakes, from the 

 Hetch Hetchy and Yosemite valleys to Tuolumne Meadows. 



2. P. bistortoides Pursh. Stems several from a woody 

 root, 6 in. to usually 1 or 2 ft. high. Basal leaves oblong or 

 lanceolate, 3 to 5 in. long, y 2 to 1 in. wide, distinctly petioled; 

 upper leaves smaller, sessile. Flowers white, in compact 

 cylindric or roundish heads terminating the stem. 



The white flower-heads of this Polygonum are conspicuous 

 above the green herbage in nearly all of the mountain 

 meadows, especially where the soil is wet, being of tall 

 stature when growing at moderate altitude, but much dwarfed 

 along its upper limits. 



3. P. amphibium L. Water Persicaria. Aquatic perennial 

 with stout stems not branching above the rooting base, sel- 



