8G 



Tratjns. Both species (7". JioelenouJc.t and T. rdcciiiosux) 

 are most cliaracteristic of the open ^'eld of stony hillsides in 

 the reg-ion bordering' the Karroo, and also of the Sand Yeld 

 region of Griqualand West and Bechiianaland, but T. race- 

 VIO.SU.S occurs in similar situations in Natal and the Transvaal. 

 Thej' are small xerophytes, with rather rigid leaves, which 

 have spinuloush' ciliate margins. The ghimes also have sjjiny 

 hooks. They are reckoned fairlj^ good grazing grasses in spite 

 •of their xerophytic character. 



Tricliolaeiia. T. ai-eiunin is important in the sandy plains 

 of the West, T. capensis is from the Central Cape and the 

 Free State, T. brevipila from Namaqualand, all being xero- 

 phytic species. T. glabra is a rare Natal species. T. setifolia 

 is an important jiioneer in the early stages of grassland over 

 the Eastern side. It grows in compact tufts and has filiform, 

 setaceously convolute leaves. T rosea in its perennial forms 

 colonizes stony hillsides, and is widely distributed over the 



Fio 



20. — Transverse Section of a portion of a leaf of Tricholaena ro<ea 

 (X a'jout 60). 



drier regions from West to E;ist, but the semi-anniuil forms 

 are peculiarly characteristic of cultivated mealie fields, and 

 waste land generally. It becomes completely dominant and 

 forms a short-lived grass stage in the Sub-sere. Its native 

 name is umKuana. Its seeds have been exported, and it has 

 been grown in India and elsewhere under the name of "Natal 

 Eed Top grass," but in South Africa it is not considered to 

 be of much agricultural value. A transverse section tlirough 

 its leaf is shown in Fig. 20. It agrees with Setaria and 

 Digitaria and Fanicum. There is a fair amount of scleren- 

 cliyma, but the bundles are not girdered. The motor cells are 

 conspicuous, but the leaf is rarely folded even in dry weather, 

 though it rolls up slowly wlien the plant is uprooted. The 

 ridges are almost obsolete. 



Triolioptery.K. T . simpler with its three varieties, minor, 

 crinita and sericea is common in the Grassveld of Natal and 



