268 



cxxiiiD. URTiCACE^ (Rendle). 



[Pilea. 



thin ; albumen almost none ; cotyledons broad. — Annual or peren- 

 nial herbs, sometimes shrubby at the base. Leaves opposite, stalked, 

 those of a pair equal or unequal, entire or toothed, 3-nerved. Sti- 

 pules connate into one, intrapetiolar. Flowers in axillary 1 -sexual 

 or 2-sexual cymes ; cymes sessile or stalked, sometimes densely 

 capituliform, sometimes paniculate. 

 Species about 200, widely distributed throughout the tropics. 



Leaves of a pair markedly unequal, elliptic, margin 



entire 



Leaves of a pair generally subequal, ovate or lanceo- 

 late (elliptic in 13, P. usamharensis), margin 

 serrate or crenate-serrate. 

 Flowers forming false sessile whorls at the nodes . . . 

 The four uppermost leaves forming an apparent 

 whorl subtending a cruciate dense inflorescence 

 Flowers not in false whorls at the nodes nor specially 

 associated with the uppermost leaves. 

 Inflorescence much shorter than the petioles ; 

 flowers crowded in dorsiventral cymules 

 which are sometimes very reduced ... 

 Inflorescence generally laxly paniculate or dicho- 

 tomous. 

 Plant shrubby 

 Plant a herb. 

 Ivcaves ovate. 



Plant 2^ ft. high ; lateral pair of nerves 



reaching to base of leaf- tip ... 

 Plant \ to 1 i ft. high ; lateral pair of nerves 

 ceasing well below the base of leaf-tip 

 Leaves lanceolate 

 Flowers contracted into one or more stalked heads. 

 Ix^aves ovate. 

 Achene ovate. 



Stipules membranous, persistent ... 



Stipules deciduous 



Achene lenticular ... 



Leaves lanceolate 



Leaves elliptic 



Leaves trapezif orm 



1. P. manniana. 



2. P. ceratomera. 



3. P. tetraphylla. 



4. P. angolensis. 



P. nriiccefolia. 



I. p. manniana, Wedd. in DC. Prodr. xvi. i. 117. Dioecious, 

 somewhat shrubby, apparently climbing, glabrous. Stem terete, 

 smooth ; internodes 2-4 in. long. Leaves of a pair unequal, oblong- 

 elliptic to elliptic, acuminate, the larger petiolate, 3-6 in. long and 

 lJ-3 in. wide, with a rounded base, the smaller subsessile, 2-3 in. 

 long, 1-1 J in. wide, with a cordate somewhat amplexicaul base, 

 margin subentire or inconspicuously serrulate below the apex, tripli- 

 nerved, nerves prominent beneath and joined by conspicuous curving 

 secondary veins, network of veins also prominent, the meshes bearing 

 numerous minute linear cystoliths ; petiole of larger leaf IJ-l-^ in. 

 long. Stipules oblong-ovate, deciduous, about 5 lin. long. Cymes 



