276 THE FLOBA. 



Analysis of the Genera. 



Involucre jnst like a calyx, involving a single, large flower. Calyx funnel-form, 



corolla-like, the limb entire. Four-o-dock. Mieab'ilis. 1 



Involucre involving 2-5 small, roae-red flowers. W. S. Oxyb'aphus. 



Involucre none, or minute braotlets. Flowers minute. S. Boebhaa'via_ 



MIKAB'ILIS. Marvel-of-Peru. Pour-o-clock. 



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



border, infinite in variety "of color, opening about 4 o'clock, p. n. t 



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



8 M. longiflo'ra. Long-fi. F. Diffuse, viscid. Calyx tube downy, very long. 1 Mex. 



Order CII.— POLYGONACEJE. Knotweeds. 



Herbs witli alternate Zeawea,'' swollen joints, and with 

 stipules sheathing the stem above the joints ; flowers raoemed, perfect; 

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

 stamens 4r-12 ; ovary 2 or 8-styled, 1-celled, 1-seeded in fruit. 



Analysis of the Genera. 



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



* Calyx 6-parted. Stamens 9. Sepals all similar. Bh/ubarb. Eheum. 



* Calyx 6-parted. Stamens 6. Hiner sepals large. Loch. Sorrel. Epmex. 



* Calyx 5-parted (irregularly 4-parted in one species) a 



a Sep., the 3 inner fringed. Fls. solitary. S. Fringe Knotweed. Thysanel'la. 



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'ohum. 1 



b Pedicels clustered in the bract. Sepals all open. Buckwheat. FAQOPY'Emi, 



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

 white, red, or greenish. Mojy-Aug. 

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



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



§ Stems erect or deourdbent, unarmed. Leaves hardly ever cordate. . ...a 



