Buchanan. — On a Specimen of Hemitelia smithii. 217 



Aet. XXX. — On a remarkable branching Specimen of 

 Hemitelia smithii. 



By J. Buchanan, F.L.S. 



{Read before the Wellington Philosophical Society, 19th January, 1887.] 



Plates XII., XIII. 

 The visitor to the slopes of Mount Cargill, near Dmiedin, may 

 have noticed the marked abundance of that beautiful tree-fern 

 Hemitelia smithii, which often attains there a height of 20-30 feet ; 

 and he may also have noticed a strong tendency in this species 

 to divide at the top of the stem into two, and sometimes three, 

 branches. But a remarkable departure, however, from this 

 limited terminal branching has been discovered, which forms 

 the subject of the present paper. The accompanying sketch, 

 drawn from measurements, proves the tree to have been 16 feet 

 in height, and that it has 16 branches, as also several buds. 

 The budding and branching may proceed from any part of the 

 stem, and the specimen has several branches diverging in various 

 directions, which again divide, as in dicotyledonous trees. The 

 accompanying drawings (Plates XII. and XIII.) have been 

 sketched by measurements taken fi-om the fallen tree, it having 

 recently been cut down by some boys. 



The transverse sections are intended to illustrate the method 

 of branching in this specimen of tree-fern ; they are all drawn one- 

 third natural size, except diagram A B, which is -^-g natural size. 



There is one remarkable feature in connection with the true 

 or inner stems and branches of tree-ferns : that is, the point of 

 attachment of the branch with the inner or true stem does not 

 increase much in diameter for several inches from the parent 

 stem ; it then gradually enlarges in an upward direction, and 

 becomes covered by the fibrous mass. A weakness in branches 

 might be suggested from this ; but the great strength of tree- 

 ferns is due to the strong fibrous matter enveloping them, which 

 is remarkably strong, and would prove as reliable for a trans- 

 verse strain as many timbers ; they have often been used for 

 short bridges, both as stringers and flooring. 



In the diagrammatic section, A B, is shown the method of 

 branching in this tree-fern : a branch is produced fi-om a small 

 bud, which pushes its way through the woody inner or true 

 stem of the tree, and also the close fibrous outer covering. (See 

 longitudinal section of A 1, where a transverse and longitudinal 

 section is shown of the method of branching.) The large 

 sections [B B and B 3) are cut 3 feet above A, showing the 

 increase of size in 8 feet of the central core. 



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