50 SUMMARY OF CURRENT RESEARCHES RELATING TO 



ceous lianes belonging to the tribe Landolphieae. The most wide- 

 spread — Carpodinus lanceolatus — does not yield caoutchouc. _ The 

 species which yields most of the product is Landolphia Tholloni ; the 

 aerial shoots contain no caoutchouc in their latex, but the cortex of the 

 long rhizomes is rich in an excellent product. A third species, hitherto 

 undescribed, is L. humilis, in which the caoutchouc is confined to the 

 subterranean rhizomes ; it contains less of the product than does 

 L. Tholloni. 



Leaf- Venation and Chemical Constituents of Eucalypts.*— R. T. 

 Baker and H. G. Smith find that there is a marked agreement between 

 the chemical constituents in the oils and the venation of the mature 

 lanceolate leaves of the several species of New South Wales Eucalypts, 

 thus forming the genus into fairly well-marked groups. There is reason 

 to suppose that a gradual deviation from a type has taken place, and 

 that the formation of characteristic constituents in these oils has been 

 contemporaneous with the characteristic alteration or deviation of the 

 venation of their leaves. 



Gums, Resins, and other Vegetable Exudations of Australia.!— 

 J. H. Maiden gives a list of the genera and species yielding gums, &c, 

 arranged in families, with notes on the plants and their exudations. It 

 is followed by "a tentative bibliography of Australian vegetable 

 exudations." 



Structure and Development. 

 Vegetative. 



Conifer Wood from the Turf-Pits. f — L. Geneau de Lamarliere 

 has investigated the structure of semi-fossilised woods from turf-pits in 

 the marshes of Saint Gond, now for the most part dry. He concludes, 

 from examination of their remains, that during the tertiary period, 

 conifers which reached a great height existed in Champagne, thus 

 confirming the statements of previous writers. The wood shows a 

 recognisable microscopic structure, though prof oundly modified structur- 

 ally, physically, and chemically. From the morphological point of view, 

 he describes a network of intercellular lamellae, modified only by the 

 amount of compression to which the trunk has been subjected, cells 

 which apparently have undergone no change (refringent cells), and 

 others where the internal thickening layers have disappeared or been 

 transformed into an amorphous annular or continuous mass. From the 

 chemical point of view, the changes are very marked. The intercellular 

 network still gives the reactions of pectic compounds, but it is probable 

 that pectic acid occurs in the free state and not in combination with 

 lime as appears to be the case in plants in the normal condition. In 

 addition, lignin occurs and perhaps also phosphates. _ 



The refringent cells seem to be elements which have not been 

 attacked by destructive agents. Their walls still contain cellulose, 

 pectic compounds, lignin, and phosphates. The amorphous substance 



* Journ. and Proc. Roy. Soc. New South Wales, xxxv. (1902) pp. 116-23 (1 pi.). 



t Tom. cit., pp. 161-212. 



X Rev. Gen. Bot., xiv. (1902) pp. 241-53, 300-15 (15 figs, in text). 



