276 THE FLORA. 
Analysis of the Genera. 
Involucre just like a calyx, involving a single, large flower. Calyx funnel-form, 
corolla-like, the limb entire. Four-o-clock. Mrras’ tis. 1 
Involuere involving 2-5 small, rose-red flowers. W.S. Oxyp’aruus, 
Involucre none, or minute bractlets. Flowers minute. 8. Bornwaa’via, 
MIRAB’ILIS. Marvel-of-Peru. Four-o-clock. 
1M. Jala’pa. Peruvian F. Leaves ovate, subcordate. Fils. stalked, with a large 
border, infinite in variety of color, opening about 4 o’clock, Pp. Mm. + 
2M. dichotoma, Mexican fF. Erect, smooth. Calyx with a small border. t+ 
3 M. longifio’ra. Long-ft. F. Diffuse, viscid. Calyx tube downy, very long. + Mex. 
Orpen CII—POLYGONACEA. Knotweeds. 
Herbs with alternate leaves, swollen joints, and with 
stipules sheathing the stem above the joints ; flowers racemed, perfect; 
calyx persistent ; sepals 4-6, imbricated, distinct or united at base; 
stamens 4-12; 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, Oxyr’ta. 
* Calyx 6-parted. Stamens 9. Sepals all similar. Rhubarb, Rusum, 
* Calyx 6-parted. Stamens 6. Inner sepals large. Dock. Sorrel. Rvuex, 
* 
Calyx 5-parted (irregularly 4-parted in one species)....a 
a Sep., the3inner fringed. Fls.solitary. 8. Fringe Knotweed. TaysanEL’La, 
a Sepals not fringed, entire or nearly so....b 
b Pediccls solitary. Sep. all open or 8 closed on the fruit. M.S. Poryraoner’/za. 
b Pedicels usually clustered. Sepals all closed on the fruit. Potyo’onum. 1 
b Pedicels clustered in the bract. Sepals all open. Buckwheat, Fagory/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 8. Nut lens-shaped 
or 8-cornered.—Herbs with swollen, sheathed joints. Flowers small, 
white, red, or greenish. May—Aug. 
§ Steins climbing, with reversed prickles. Leaves cordate-sagittate....19, 20 
§ Stems unarmed, twining. Leaves cordate-hastute....17, 18 
§ Stems erect or decumbent, unarmed. Leaves hardly ever cordate....a 
