BOOKS AND CURRENT LITERATURE 185 



plains whit'li are untouched by the northeast monsoon or the winter 

 storms. . . . Accepting savanna as the type of our formations we 

 find the following transitions (types) which result solely from cdaphic 

 causes." 



1. Xerophytic Woodland develops on hillsides in the northeastern 

 part of the area. It is a fairly close growth of deciduous trees in which 

 the characteristic species is Terminalia tomentosa (Combretacese) with 

 which are associated Boswellia serrata (Burscracese), Phyllanthus em- 

 hlica (Euphorbiacese), Bassia latifolia (Sapotacese), Aegle marmelos 

 (Rutacese) and Tectona grandis (Verbenaceae), the teak. In more 

 level places with deeper soil the forest gives way to a grass association 

 with interspersed trees of Terminalia, Bassa, etc. 



2. Savanna Woodland is found on rocky soil. It is a more open 

 growth than the association just considered. The same trees occur, 

 together with various others, such as species of Stercidia, Diospiros 

 and Anogeissus (Combretacese). There are a number of shrubs but 

 none abundant except Helicteres isora (Sterculiacese) 



3. Thorn Savanna is a highly xerophytic association on gravel and 

 on compacted sand where water does not easily penetrate. The char- 

 acteristic plants are thorny shrubs and small, thorny trees. The 

 authors characterize it as a "highly aggressive" community. Species 

 of Zizyphus (Rhamnacese) dominate large stretches of country. Aban- 

 doned fields often grow up to thorn savanna in which Capparis aphylla. 

 is the chief species, or to an association of Zizyphus rotundifoUa, Cassia 

 auriculata and Calotropis pr'ocera ( Asclepiadacese) . Common lianas of 

 the thorn savanna are Asparagus racemosa, Leptadenia reticulata 

 (Asclepiadacese) and Cocculus villosa (Menispermaceae). Undergrowth 

 is composed of low herbage, especially Lepidagathis trinervis (Acan- 

 thaceae) and Convolvulus pluricaulis. Grasses belong to the genera 

 Aristida, Andropogon, Tragus, Gracilea, Chloris, etc. The first two 

 are of tuft form (cf. "bunch grasses" of our western plains). 



4. Butea Savanna develops on sand that has considerable humus.' 

 It is dominated by a small tree, Butea frondosa (Leguminosse) , with 

 occasional scattered individuals of such large trees as Bassia latifolia 

 and Bombax malabaricum. Common undershrubs are Cassia auricu^' 

 lata and Triumfetta rotundifoUa (Tiliacese). Grasses are the same as 

 in other savannas. The authors remark that the association demands 

 further ecological study. While they do not say so it may be judged 

 that the Butea Savanna, in its various modifications, represents the 

 climatic climax plant community: A modified type of the association 



