104 REPORTS ON THE STATE OF SCIENCE. — 1915. 



might be attached to particular botanical features peculiar to u«rtain 

 species or groups. 



A corresponding comparative constancy in chemical characters is 

 also evident in the case of the kinos or exudations of the several species ; 

 these, in most instances, show a grouping parallel with that of particular 

 constituents of the essential oils and are therefore in conformity with 

 certain characteristic botanical features of the species. In fact, this 

 botanical and chemical agreement appears to be represented by practi- 

 cally all the members of the genus. 



The suggested evolutionaiy development of the Eucalypts receives 

 considerable support from the study of these exudations, as there is as 

 much diversity in the chemical composition of the kinos as has been 

 found to be the case in their oils (14). 



The exudations of the Eucalypts do not contain gum but are all 

 astringent and contain tannins. These tannins, however, differ con- 

 siderably from one end of the genus to the other; both in relative 

 astringency and in rapidity of gelatinisation they are widely separated, 

 and this variation is also obvious in the case of the other constituents of 

 the exudations, both crystalline and amorphous. 



Some of the members of the genus Angophora show a veiy close 

 affinity, both botanically and chemically, with those members of the 

 genus Eucalyptus which are included under what is generally known as 

 the ' Bloodwood ' group. This relationship is indicated by the general 

 appearance of the tree, by the venations of the lancellate leaves, by the 

 composition of the essential oils, by the presence of caoutchouc cover- 

 ing the very young leaves, and by the composition of the kinos or 

 exudations. The kinos of most of the Angophoras and of some Euca- 

 lypts having a similar leaf -venation, E. calopliyUa for instance, con- 

 tain the crystalline substance Aromadendrin, the other crystalline body 

 found in some Eucalyptus kinos (Eudesmin) being absent (15). The 

 terpene in the leaf-oils is pinene but neither phellandrene nor cineol is 

 present, except in small amount ; the leaf-venations resemble the general 

 markings of a feather. The anthers of this group are parallel antherse ; 

 the cotyledons of the seedlings are large and broad. As the leaf-vena- 

 tion in the Eucalypts changes into the peculiar arrangement charac- 

 teristic of species yielding cineol-bearing oils, Eudesmin is found in their 

 kinos and this substance increases in amount by easy stages through 

 the several species until, in the kinos of the typical boxes — E. hemi- 

 phloia, for instance — about 10 per cent., is present. Aromadendrin also 

 occurs in these ; no Eucalyptus kino so far tested in which Eudesmin is 

 found has been without Aromadendrin. The anthers in this large group 

 are not all parallel but show variations ; the cotyledons of the seedlings 

 also vary much in size and shape. As the leaf-venation changes into the 

 peculiar structure indicative of the phellandrene-bearing oils the con- 

 stitution of the kinos also changes ; both Eudesmin and Aromadendrin 

 are absent from all the typical kinos of this gi'oup ; the colour given by 

 the tannins with ferric chloride differs considerably from that shown 

 by the kinos of the members of the other groups. The anthers of the 

 species belonging to this group are kidney-shaped (Eenantherse). The 

 rapidity with which the kinos of this group gelatinise in tinctures is 



