466 SUMMARY OF CURRENT RESEARCHES RELATING TO 



degradation product of xanthophyll and carotin. The soluble yellow 

 pigment, obtained by boiling yellow leaves, is a mere artificial product, 

 and has nothing to do with the colouring of leaves while they are still 

 alive, although it acts in this way after they are dead. 



General. 



Phytecology of the Eastern Part of Kabylia.* — G. Lapie has 

 studied the vegetation of this region, and finds five distinct zones. The 

 ridges of Djurdjura form the cedar zone, and are characterised by such 

 trees as Cedrus Libani, Acer obtusatum, Quercus Mirbeckii, etc., shrubs 

 as Crataegus laciniata, Lonicera arborea, etc., and small plants such as 

 Pmonia corallina, etc., together with a few mosses. The Arbalou and 

 the older summits form the oak zone, the eastern portion being covered 

 with Quercus Ilex, while the western sides abound in Q. Suber. The 

 third zone is mainly characterised by deciduous oaks, e.g. Quercus 

 Mirbeckii and Q. Afares, with an abundant undergrowth of Erica arborea, 

 or in more shady districts various species of Genista, Cytisus, Pteris, etc. 

 The fourth zone comprises the lower summits of Numidia, a part of 

 Cretace and Medjanien, and here the sandstone ridges are covered with 

 Quercus Suber, together with Thymus numidicus, Erica arborea, etc. 

 The clay soil of the lower districts and of Numidia is covered with the 

 olive tree, and forms the fifth zone. The undergrowth is composed of 

 Pistacia Lentiscus, etc. In general, the sides and summits of the lofty 

 peaks have a xerophytic vegetation ; the summits of lower peaks with a 

 calcareous substratum have similar plants, but if the substratum is of 

 sandstone, the plants are tropophyllous. On the low grounds the 

 chemical and physical nature of the soil exerts great influence on the 

 vegetation, being xerophytic in the region of the olive tree and semi- 

 xerophytic with the evergreen oak. The summits of medium height 

 present the highest degree of humidity, while the presence of a sand- 

 stone substratum diminishes the xerophytic character of the vegetation. 



Philippine Woods.f — F. W. Foxworthy contributes a preliminary 

 paper with the object of facilitating a ready identification and classifica- 

 tion of the commoner Philippine woods. The present paper contains a 

 general and technical discussion of the gross morphology and minute 

 anatomy of wood. This is followed by a brief description of its physical 

 and chemical properties, and information connected with its durability 

 and decay. The author then gives short notes on the structure, 

 appearance, common names, range and usefulness of individual species, 

 and finally a very complete index. It is hoped that this will put an end 

 to the confusion now existing concerning the woods of Manila, and will 

 lead to a better understanding of their uses, and the discovery of further 

 uses. It may also be expected that the present work, together with the 

 parts to be published later on, will be a help to discovering the relation- 

 ships existing between the woods of the Philippine Islands and those of 

 the rest of the world. 



* Comptes Rendus, cxlvi. (1908) pp. 649-52. 



t Philippine Journ. Sci., ii. (1907) pp. 351-404 (4 pis.). 



