8: 



the Transvaal, and often forms clans or societies. T. flarida 

 is a Trausvaal High Veld species, and T. nniiosu is a xeru- 

 phj'tic sutfrutescent species from (jriqualand West. T. dregeana 

 belongs to the hydrosere in Natal, being found near streams. 

 It is also recorded for the Transvaal and the Shire Highlands. 

 All the species are tropical. 



Trirapliis. This is chieilv a AVestern genus from Nama- 

 qualaud, Hereroland and Ambohuid. T. elliotii, T. purpurea, 

 T. fleclai, T. nana, T. purpurea, T. rauiosissimti, T. schinzii 

 are representative Western species of which cue or two (T. 

 fhclii, T. nana) extend eastward through the Kalahari to 

 Bechuanaland and Griqualand West. T. nana is a dwarf 

 annual, scarcely an inch high, "and all the species are very 

 xerophytic. T. rehmauni has quite a different distribution", 

 from the Cape at Uitenhage through the Free State, Transvaal 

 and Natal. On the eastern side it is a Mountain Veld species 

 or it grows in open stony Veld. No records for Natal are 

 given in the Flora Capensis. 



'J'risotum pnmilum very rare in the South West, probablv 

 introduced. 



Fig. 21. — Transverse Section of a portion of a leaf of Tristacliya ieucothrix 



(x about 50). 



Tristacliya. T. lencoth ri.r is widely distributed over the 

 whole Eastern region, and forms definite societies in climax 

 o-rassland. T. reltniauiu is common in the Transvaal High 

 Veld and T. hiseriafa is a Basutoland species. Thej' are coarse 

 tufted grasses similar to the Andropogons. Fig. 21 shows a 

 transverse section of part of the leaf of T. Jeucotlrrij'. The 

 ridges are practically obsolete, and there is little sclerenchyma. 

 The motor cells are on the surface, and not at the bottom of 

 grooves, but they cause the leaf to roll up. Panicuiu serratuni 

 is similar. ■ 



I'relylriim sqiiarrosiim. Fairly common in the High 

 Veld of Natal and the Transvaal. It resembles T nicliypngon 

 pah/iiiorpJtus. The variety roljiista is larger and stouter. 

 Fill". 22 shows a cross section of the leaf. The ridges are 



