475 



(c) The Operculum. 

 Shape (including Historical, 1788 (L'Heritier) ; 1797 (Smith) ; 1825 (De Candolle) ). 

 Sculpture (including calyx-tube). 



Comparative length of operculum and calyx-tube. 



Note on E. tetraptera. 

 Rather solid operculum. 



Colour of operculum. 



Shape. 



17S8. — L'Heritier, in his original description of Eucalyptus, has the words. 

 " Operculum superum, integerrimum, truncatum " (Operculum above, quite entire 

 truncate). He was describing E. obliqua, from Tasmania. See Plate 5, Part II. 



1797 " There is not a more natural genus in the whole. Linnean system than this (Eucalyptus). 

 It is clearly characterised at first sight by the singular operculum which closes the calyx, and covers up 

 the stamina and style till they arrive at maturity." (Smith in Trans. Linn. Soc, iii, 283, 1797.) 



He grouped a number of species according as the operculum was conical or 

 hemispherical, as follows. He only knew twelve species, and divided them into two 

 classes according to the operculum : — 



1. Operculo conico. 



E. robusta. E. rcsinifera. 



E. pihdaris. . E. capitellata. 



E. tereticornis. E. saligna. 



2. Operculo hemisphserico. 



E. botr i/o ides. E. obliqua. 



E. hcemastoma. E. corymbosa. 



E. piperita. E. paniculata. 



This was followed by Willdenow [Spieeies Plantarum, 1799) and Persoon 

 (Synopsis Plantarum, 1807). 



1825. — De Candolle, in his Prodromus III (1825), of which Don (Dichlamydeous 

 Plants), ii, 818 (1832), is mainly a translation, also used the operculum in his subdivision 

 of the species with alternate leaves. He recognised five distinctive shapes : — • 



1. Conical, longer than the calyx-tube, e.g., E. cornuta. 



2. Conical, equal in length to the calyx-tube, e.g., E. stellulaia. 



3. Xearly conical or hemispherical, shorter than the calyx-tube, e.g., E. amygdalina. 



4. Hemispherical, much broader than the calyx-tube, e.g.. E. gomphocephala. 



5. Depressed in the centre, shorter than the calyx-tube, e.g., E. globulus. 



