86 



Tragus. Both species (T . koelerioides and T. racemosus) 

 are most characteristic of the open Veld of stony hillsides in 

 the region bordering- the Karroo, and also of the Sand Veld 

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

 mosus occurs in similar situations in Natal and the Transvaal. 

 They are small xeroplrytes, with rather rigid leaves, which 

 have spinulously ciliate margins. The glumes also have spiny 

 hooks. They are reckoned fairly good grazing grasses in spite 

 of their xerophytic character. 



Tricholaena. T. arenaria 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 pioneer 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 



Fij 



20. — Transverse Section of a portion of a leaf of Tricholaena rosea 

 (x about 60). 



drier regions from West to East, but the semi-annual forms 

 are peculiarly characteristic of cultivated mealie fields, and 

 waste land generally. It becomes completely dominant and 

 iorms 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 

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

 be of much agricultural value. A transverse section through 

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

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

 ■chyma, 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 when the plant is uprooted. The 

 ridges are almost obsolete. 



Trichopteryx. T . simplex with its three varieties, minor, 

 crinita and sericea is common in the Grassveld of Natal and 



