NOTES OX ELXALYPTUS RISDOXI, HOOKER, 



(Pl. X, XI AND XII.) 



By L. Rodway. 



(Read October loth, 19 lo.) 



The limits that shall be assigned to this species is a 

 puzzle to the student. Hooker described the plant from 

 material gathered at Risdon. He figured it in his Flora 

 Tasmaniae. It is abundant on the dry hills from Risdon 

 to Rokeby, besides elsewhere, exactly in the form of his 

 description. In this type-form the leaves are opposite, 

 sessile, connate, and so covered with pale wax as to be 

 of a pale glaucous colour. The flowers and fruit difYer 

 in no detail from those of Peppermint (E. amygdalina 

 Lab), except that they are larger. The fruit is pyriform 

 or turbinate, even on the same tree, and ranges in dia- 

 meter from about 9 m.m. to 13 m.m. In E. amygdalina 

 the fruit is nearly always turbinate, and ranges from 5 

 m.m. to 7 m.m. diameter. These measurements appear to 

 be constant, and may in critical cases be taken as a 

 sign of affinity. We all recognise the close relationship 

 of the two, and the prince amongst Australian botanists, 

 Baron von Alueller, insisted upon combining the two 

 under one name. This is a clubbing that is not likely 

 to be adopted by those familiar with these trees in the 

 forest. Another feature that appears to be constant is that 

 E. Risdoni and its varieties always retain some degree 

 of glaucosity, while in E. amygdalina and its varieties 

 this peculiarity is absent. 



The leaves of the typical E. Risdoni are arranged in 

 opposite pairs, and each pair is broadly connate across 

 the stem. They average in length 4 cm., and in greatest 

 breadth, which is at the lowest third of length, 3 cm.; 

 they are broadly ovate with usually an acute apex. The 

 leaves vary greatly in shape, in response partly to 

 heredity, partly to local conditions. In this respect 

 the tree seems to respond to the stimulus of nutriment in 

 a truly remarkable manner, but we can generally trace 

 in the plexus of forms two lines of variation, one 

 assuming the character of variety elata, the other of 



