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DESCRIPTION. 



CCCXCIV. E. Dlxsoni Wakefield, n.sp. 



Arbor parva 30-50 pedes alta ; cortice persistente, fibroso usque ad ramos parvos ; foliis junioribus 

 heteromorphicis, oppositis pallido-viridibus vel glaucis, angusto vel lato-lanceolatis ; foliis maturis 

 gracilibus, clavatis, operculo obtuso ; fructu campanulato vel cupulare, 7x6 cm. 



" Usually a small tree, rarely exceeding 50 feet in height and 2 feet in diameter at the butt; the 

 bark persistent to the finer branchlets ; the texture of the bark is fibrous, being almost intermediate between 

 the Peppermint type and the Stringybark type. 



Leaves heteromorphic ; mature leaves lanceolate-falcate, disposed vertically and drooping from 

 the branchlets ; intermediate leaves lanceolate, and some pale glaucous. Sucker leaves, two distinct 

 forms to be found on the one plant — a small form very similar to the sucker leaves of E. radiata, but more 

 ovate and pale green, not glaucous ; the larger form closely resembles the suckers of E. dives, white glaucous, 

 sessile and opposite, but usually more acutely acuminated ovate. 



Fruit resemble E. dives, in clusters of six to fifteen. 



"Range. — 'Found in the Yambulla district, and specimens from which the type is described were 

 collected 3J miles east from Yambulla Mountain, where a belt of considerable size is to be found. 



" It is found in ecological association with E. Consideniana and E. evgenioides. There can be little 

 doubt of its origin, as E. radiata x E. Consideniana, both of which occur widely distributed in the district. 

 Occasional trees have also been observed near Timbilica and Yambulla and along the South Coast, south 

 from Moruya, and it is probable, therefore, that its range may be considerably extended. 



" The most remarkable feature is the great diversity of form exhibited in the sucker leaves. A 

 clump of suckers at the butt of the tree will usually be found to have the large glaucous leaves approaching 

 E. dives. Suckers produced from adventitious buds higher, as the result of fire or other accident, are usually 

 closely approaching E. radiata. Suckers about midway in character are also to be found. (The 

 intermediate-leaved stage in nearly all species is very interesting. — J.H.M.) 



" Heteromorphic Leaves and Ancestral Characters. — There appears to be considerable evidence in 

 support of the view that ' suckers ' produced from adventitious buds exhibit characters approximating 

 the ancestral form of the species. In the development of an individual from such adventitious buds there 

 appears to some degree to be a recapitulation of phylogeny. How far such characters may be justly so 

 interpreted, and how far such forms are evidence of adaptations to new environmental conditions it is 

 difficult to estimate. 



" The development of adventitious buds in the case of E. Dixsoni is of considerable interest from this 

 Point of view. The adult species is perhaps more closely allied to E. Consideniana than to any other species. 

 Only on very close examination of the bark is it possible to discriminate between the two species in the 

 absence of leaves and fruits. These latter indicate affinities with E. radiata, and the leaves are almost 

 i ntermediate in character. There can be little doubt that the new species is a product of these two widely 

 different species. 



" A study of the development of ' suckers ' from an adventitious bud in E. Dixsoni is most 

 instructive. The young shoots develop thin green lanceolate leaves almost identical with those of E. radiata, 

 thus indicating its phylogenetic relationship. Such suckers may persist for some time, and several have 

 been measured exceeding 2 feet in length. Eventually, however, these delicate green leaves are replaced 

 by large, coarse, glaucous leaves, very similar to the familiar sucker leaves of E. dives. Indeed, when 

 the species was first observed the following note was made on the spot : — ' A belt of a curious form 

 exhibiting relationships with E. Consideniana and E. dives occurs about 1 mile north from the eastern end 

 of Captain's Swamp.' Subsequent examination, however, clearly indicated its relationship with E. radiata 

 and not with E. dives, as the secondary suckers would suggest. 



