14] VEGETATIONAL TYPES OK TROPICAL LANDS 44I 



forests may be relatively uniform, a feature of most other types of 

 monsoon forests is the variety of tree-species involved, which may 

 number forty or fifty in a single tract. In general, however, both 

 flora and vegetational luxuriance are markedly poorer than in the 

 tropical rain forest, though the most striking diflterence lies in the 

 seasonal nature of the monsoon forest. 



2. Savanna-woodlands or ' parklands ' are often found where the 

 rainless period is more prolonged and the annual rainfall less heavy 

 than in true closed forest. The trees are mostly widely scattered 

 save in favourable situations (such as occur near watercourses), show 

 increasing xerophily and resistance to drought as water-availability 

 decreases, and are often leafless during the dry season. The 

 vegetation is open and park-like, being rich in terrestrial herbs and 

 especially Grasses, but very poor in lianes and epiphytes. Bulbous 

 and other geophytes are often abundant. The trees are commonly 

 stunted to little more than tall shrubs, being usually much less than 

 20 metres high and sometimes overtopped by tall Grasses during 

 the rainy season. Although normally various, they are most char- 

 acteristically and widely members of the Pea family (Leguminosae), 

 which frequently dominate alone. Some of the trees may be quite 

 lofty ; but usually they are of lowly stature, often with squat stems 

 and thick fissured bark, the crowns being commonly flattened 

 or umbrella-shaped — allegedly in relation to wind, though this 

 presumption has been questioned. Thus Mr. A. C. Hoyle [voce] 

 believes that the causal factors are complicated and include high 

 insolation at times of limited water-supply. The leaves of the trees 

 are usually xeromorphic and their buds well protected, but flowering 

 frequently takes place late in the dry season. 



In some places, as for instance in South Africa, it is contended 

 that the more open parkland or ' tree-veld ' is successional, the 

 scattered Acacias and other trees attracting Birds and Mammals that 

 drop seeds around. In this manner a considerable variety of other 

 trees, shrubs, and climbers may be brought in and locally oust the 

 tall Grasses, so that a patchy type of savanna-woodland develops. 

 Even this may not be truly climax but due to edaphic or biotic 

 influences (particularly fire), and indeed it may well be that most 

 savanna-woodland is a fire climax in which the trees become self- 

 selected for fire-resistance. 



In these well-lighted, open types of woodlands a few small lianes 

 and epiphytes may occur, though often the latter, particularly, are 



