y6 BUCKWHEAT FAMILY 



POLYGONACEAE. Buckwheat Family. 

 Herbs and low shrubs with simple leaves and small regular 

 flowers without petals. Stamens 4 to 9. Calyx 3 to 6-cleft. 

 Ovary 1-celled, mostly triangular, becoming a dry 1-seeded 

 fruit (akene). 



Leaves without stipules; flowers surrounded by an involucre. 

 Involucre 1 or 2-flowered; annuals. 



White-woolly plant; involucres sessile 1. Chorizanthe. 



Green plant; involucres peduncled 2. Oxytheca. 



Involucre several-flowered; coarse perennial plants (ex- 

 cept E. virgatum) 3. Eriogonum. 



Leaves with papery or membranous stipules sheathing the 

 stem, alternate; flowers without involucre. 

 Calyx-lobes 6, the 3 outer reflexed in fruit, the 3 inner 



erect and enlarging 4. Rumex. 



Calyx-lobes 4, the 2 outer spreading, the 2 inner erect; 



Alpine plant with roundish succulent leaves 5. Oxyria. 



Calyx-lobes 5 or 6, equal and erect in fruit 6. Polygonum. 



1. CHORIZANTHE. 



1. C. membranacea Benth. Leaves linear, entire, acute, 

 1 or 2 in. long, the uppermost and even the bracts not much 

 reduced. Involucres several in each sessile head, 1-flowered, 

 papery, the 6 teeth bristle-tipped. 



The erect, white-woolly stems of this annual are Yz to 2 ft. 

 high, simple below, but branching above and bearing several 

 or numerous bristly heads of pale flowers. It grows in dry, 

 loose soil of the foothills, reaching 4000 ft. alt. in Yosemite 

 Valley. 



2. OXYTHECA. 



1. O. spergulina Greene. Leaves linear, entire, 2 in. or less 

 long, somewhat hairy. Pedicels % to y 2 in. long. Involucre 

 4-cleft. Flowers rose-color; outer segments obtuse; inner 

 segments 3-toothed. (Eriogonum spcrgulinum.) 



This delicate annual (2 in. to 3 ft. high) has its leaves all 

 in a basal tuft and bears a simple to diffusely branched 

 panicle of small flowers on capillary pedicels. It is common 

 in loose soil of the Yellow Pine Belt. 



3. ERIOGONUM. 

 Leaves alternate or in circles or basal, without stipules. 

 Flowers on slender pedicels, several to many in each 4 to 8- 

 toothed involucre. Calyx 6-parted, persistent. Stamens 9. 

 Styles 3. 



