134 



Urticaceae. (Page 140.) 



Fleurya. This genus is nearly allied to Urtica, of which we have several 

 indigenous as well as two European species in South Africa, viz. the common 

 garden nettle, U. urens t and the large leaved Uriica dio'ua {bmmhwtet). 

 Fleurya differs from Urtica by its leaves, which are alternate, and the shape of its 

 rruitlets. Its four species are all annuals of the eastern districts. 



The structure of the stinging hairs is in principle the same as in Urtica, 

 but they differ slightly in shape. The inflated base, which contains the acrid 

 juice, probably formic acid, is set in an elastic cup; while the sharp, slantingly 

 cut apex is protected by a little knob which easily breaks off when touched, 

 leaving a very sharp, finely perforated point, similar in shape to the needle of a 

 hypodermic syringe. When touched by an animal and thereby deprived of its 

 protecting cap, the hair can easily penetrate the skin, and the acrid fluid is 

 forced into the wound by the contracting cup which surrounds its base. 



Urera tenax, a fibre plant (Natal), is figured in Transv. Agr. Rep. 1903. 



Fam. 4. Ulmaceae. 

 Tribe Celtideae. 



Trees or shrubs. Leaves simple, with stipules. 

 Flowers unisexual or bisexual, monoecious or polygamous ; 

 $ flowers in clusters; perianth simple, 4 — 5-parted; 

 stamens as many as the perianth-segments and opposite 

 them. Ovary i-celled ; styles 2 ; ovule solitary, pendulous. 

 Fruit a drupe ; seeds with scanty endosperm or quite 

 without it. Wood without laticiferous vessels. 



KEY TO THE GENERA. 



A. Fertile flowers bisexual, solitary, in the axils of the upper leaves. 



Calyx-lobes of $ fl. imbricate; styles 2, deciduous. Embryo with 

 broad cotyledons. (Plate 23.) 

 Over 70 species, 4 S. A. 



1. Celtis L. 



B. Calyx-lobes of $ fl. valvate. Embryo with narrow cotyledons. 



a. Flowers polygamous; £ and bisexual fl. often together in the same 



tuft; drupe minute, crowned by the 2 persistent styles and 



surrounded by the persistent calyx. Stipules free. 

 2 S. A. species (N.). 



(Sponia Comm.) 2. Trema Loureiro 



b. Fertile flowers all unisexual; stigmas very long and villous, 



deciduous. Stipules intra-axillary, connate. 

 1 S. A. species (E.). 



3. Chaetacme Planch, iff Harv. 



