290 THE FLORA. 



Analysis of the Genera. 



Involucre just like a calyx, involving a single, large flower. Calj^x fu.nnel-forra 



corolla-like, the limb entire. Four-o-chck. Mii;Ab'ili8. > 



Involucre involving 2-5 small, rose-red flowers. "W. S. OxYB''APHt;s. 



Involucre none, or minute bractlets. Flowers minute. S. Boeehaa^via. 



MIEAB'ILIS. Marvel-of-Peru. Four-o-clook. 



1 M. Jala 'pa. Peruvian F. Leaves ovate, subcordate. Fls. stalked, with a largo 



border, infinite in variety of color, opening about 4 o'clock, p. a. f 



2 M. dichotoma. Mexican F. Erect, smooth. Calyx with a small border. + 



3 M. longiflo'ra. Long-fl. F. Diffuse, viscid. Calyx tube downy, ve/y long, i Mex. 



Order CII.— POLYGONACE.E. Knotweeds. 



Herls with alternate leaves^ swollen joints, and with 

 stipules sheathing the stem above the joints ; Jioicers racemed, perfect; 

 calyx persistent ; sepals 4—6, imbricated, distinct or united at base ; 

 stamens 4-12 ; ovary 2 or 3-styled, 1-celled, 1-seeded in fruit. 



Analysis of the Genera. 



* Calyx 4-parted, regular. Stamens 6. Styles 2. Mountain Sorrel. Oxye'ia. 



* Calyx 6-parted. Stamens 9. Sepals all simila'-. Rhubarb. Rheum. 



* Calyx 6-parted. Stamens 6. Inner sepals larp*^. Bock. Sorrel. Ktmex. 



* Calyx 5-parted (irregularly d-parted in one specie-*) a 



a Sep., the 3 inner fringed. Fls, solitary. S. Fringe Jinoiiveed. TuYSASiih^ijA. 



a Sepals not fringed, entire or nearly so b 



b Pedicels solitary. Sep. all open or 3 closed on the fruit. M. S. Polygonel''la. 

 b Pedicels usually clustered. Sepals all closed on the fruit. Polyg''oxum. 1 



b Pedicels clustered in the bract. Sepals all opt^n. Buckwheat. Fagopy''rum. 



POLYG'ONUM. Knotweed. 



Calyx 5- (rarely 4-) parted, colored or corolla-like, the sepals all erect 

 and inclosing the fruit. Stamens 4-9. Styles 2 or 3. Nut lens-shaped 

 or 3-cornered. — Herbs with swollen, sheathed joints. Flowers small, 

 w^hite, red, or greenish. May-Aug. 



i Stems climbing, with reversed prickles. Leaves cordate-sagittate 19, 20 



§ Stems unarmed, twining. Leaves cordate-liastate 17, 18 



S Stems erect or decumbent, unarmed. Leaves hardly ever cordate. . . .a 



