11 



Pavallelanthera', the cells parallel, and the longitudinal slits consequently 

 parallel. 



This section comprises the remainder of the eucalypts, and a most 

 heterogeneous and extensive collection they are, variable in many ways. 



As a matter of fact, the anthers refuse to he rigidly marshalled into sections. 

 They sometimes display such variation of divergence of shape of cell, size, and 

 mode of dehiscence, that classification on the anthers alone becomes a matter of 

 difficulty. 



In the old collections, the difficulty is enhanced through the partiality of 

 insects for these organs ; nevertheless, examination of the anthers is always carried 

 out bv me, and it is a most useful character. 



Pollen-grains. — Mueller (Eucalyptographia, under 27. eryfhrocorys) has 

 shown that the size of pollen-grains varies in different species, but we require 

 very many more measurements than are available, to be in a position to place any 

 interpretation upon the results. The shape of the pollen-grains also varies, but 

 we have few data on the subject. 



Calyx. — The calyx, " cupula " of De Candolle and other botanists, the 

 " hypanthium " of Schauer, is no longer used for classification purposes, having 

 been proved to be so utterly variable. De Candolle (and his translator, G. Don) 

 offered a classification of the eucalypts consisting of opposite or alternate leaves 

 combined with a comparison of the size of operculum with cupula. 



Fruit. — While many botanists have more or less used the fruit as a 

 diagnostic character in Eucalyptus, and it is undoubtedly the best character we 

 have, it is due to Professor Tate to say that (op. cit.) he was the first to submit a 

 scheme for classification of the genus based on the fruits alone. He deals Avith 

 («) shape; (b) external sculpture and ornament; (c) capsular teeth; (d) capsule cells; 

 (e) fertile seeds. But examination of Professor Tate's scheme shows (through no 

 fault of his) how very imperfect and full of exceptions it is. Taking item by item 

 we find the shape in each species to vary within wide limits. The truth of this will 

 be observed in contemplation even of the single species, JE. pilalaris, dealt with 

 in this part. Personally, I very largely use the fruit (unripe fruits may be very 

 misleading) for diagnostic purposes; but in many cases it must be carefully used, 

 for it displays an enormous amount of variation. This much is proved, and I go 

 further and s^y that some fruits only appear to have an approximately constant 

 shape because we have so much to learn in regard to the range of the species and 

 consequent possibilities of variation. Of course, I at once admit the fact that some 

 species are " stronger " than others. 



To sum up, for herbarium work the anthers and fruits are the best 

 characters to go by ; for the scientific forester, the bark and the timber ; but all 

 characters display a puzzling amount of variation. 



