XCVII. NYCTAOINEJE. 309 



ill the bardencd, mostly 5-ribbed base of the calyx. — DC. Prod. 

 xiii. p. 449. 



Tropical weeds, erect or trailing. Leaves opposite, mostly petioled. 

 Flowers in irregular glomerules, rarely umbellcd, small. — B. Biirchellii, 

 Cliois., occurs about Natal, etc. 



Order XCVIII. POLYGONE^. 



Flowers bisexual or polygamous. Calyx herbaceous or 

 corolloid, 3-6-parted, persistent, often enlarginsj with the 

 fruit, imbricate in bud. Stamens ])erioynous, definite, in the 

 bottom of the perianth ; anthers 2-celled, splitting. Ovary 

 1-celled, free, compressed or triangular ; ovule solitary, erect ; 

 styles 2-3, free or more or less connate. Fruit an achene 

 (nut), rarely berry-like, more or less enclosed in the perianth. 

 Seed erect, albuminous ; radicle superior. — Herbs or shrubs, 

 with swollen joints. Leaves alternate, their bases clasping or 

 sheathing, very generally dilated into a perfect sheath (ocrea), 

 which is membranous, truncate, entire or 2-fid, often ciliate at 

 margin or torn. Flowers small. 



Calyx corolloid, 5-fid j stamens 8 ; anthers versatile ; 



stigmas capitate. 



Nuts 3-winged or crested 1. Oxtgonum. 



Nuts not winged, compressed or 3-cornered .... 4. Polygonum. 

 Calyx herbaceous, 6-fid ; stamens 6 ; anthers basifixed ; 



stigmas pencilled. 

 3 outer lobes of perianth in the fruit largest, spini- 



ferous at the angles 2. Emex. 



3 inner lobes of perianth largest, coloured or veiny ; 3 



outer smaller, not spinous 3. Rumex. 



1. OXYGONUM, Burch. 



Flowers bisexual. Calyx funnel-shaped, with a short ovoid 

 tube .constricted above the ovary ; limb corolloid, 5-parted, 

 spreading, the lobes equal, oblong, acute, marcesccnt. Sta- 

 mens 8, in the throat, equal, exserted ; anthers versatile. 

 Ovary 3-cornered ; styles 3, short, exserted, connate at base ; 

 stigmas capitate. Nut included in the calyx, Avith 3 membra- 

 nous wings or suborbicular, emarginate at each end, the faces 

 flat or furnished with a tooth expanding in a transverse line 

 into a wing, the wings wider than the seeds, entire or apicu- 

 late in the middle. — DC. Prod. xiv. p. 38. 



Herbs, with the habit of Vohjgonum. Leaves pinnatifid or entire. Ra- 

 cemes spike-like, terminal, leafless ; bracts sheathing. — 5 species, Eastern. 



