251 



This brings one to ask : — "What variation in amount of a constituent, or what 

 constituent must be present or absent in any particular case to constitute a valid 

 species ? 



Classification on oils alone associates dissimilar species. 



We should reflect when we find it stated that the oils from B. hicolor, 

 A. Cunn., are similar to those attributed to "E. hicolor,^'' and which are really the 

 product of E. Bosistoana, F.v.M. If this should be founded on fact, then it proves 

 that species with different genetic relationships resemble each other in oil-constituents. 



The classification based on oils alone places certain species and their varieties 

 in different groups, e.g. — 



E. sideroxijlon, A. Cunn. 



E. Stuartiana, E.v.M. 

 E. tereticornis, Sm. 

 E. rostrata, Schlecht. 

 It also brings together species which perhaps every other classification shows 

 us do not exhibit close affinity. Instances of this can be quoted at any time. 



To sum up, I think that characters based on the essential oils are subject to 

 variation. They do not escape the interacting laws of change any more than 

 morphological characters do. 



Explanation of Plates (37- iO). 

 PLATE 37. 



E. capitcllata, Siu. 



1. Fruits (mispliiced by White) of E. capiteUalam.y^hite'ii "Voyage," 1790, p. 22G, of the "Peppermint 



Tree." 

 '2a. Leaf ; '2b, pointed operuulum and flowers of a specimen from Dr. (J. E.) Smith, ex herb. Lambert in 



herb. Cant. Piece of the type of the species. 

 3a. Leaf ; 36, buds, of R. Brown's E. congesta from Port Jackson. 

 4a. Pair of juvenile leaves; 46, pair of leaves in the alternate stage, showing the orbicular shape. 



From Middle Harbour, Port Jackson. 

 'in. Buds ; 56, anthers ; 5c, fruits, from Oatley, George's Paver, a few miles soutli of Port Jackson. 

 Ga. Leaf ; 66, buds ; Gtf and Qd, fruits. All from the same tree, North Shore, Port Jackson. Note the 



variation in the amount of e.xsertion of the valves, and the similarity of Gd io 1. 

 [N.B. — All the above are practically identical.] 

 la. Buds ; 76, fruits, from Guy Fawkes, New England. 

 8a. Juvenile leaves in tlie alternate stage ; 86, mature leaf ; 8tf, buds ; 8(/, fruits of E. capitM<Un, var. (?) 



latifolia, Benth. (B.Fl. iii, 206). Portland, Vic, J. G. Robertson, 1842. 

 9a. Loaf; 96, buds; 9c, fruits of E. sanlalifolut var. Ba.deri, Benth. Portlaml, Vic, .J. G. Robertson, 1842. 

 10a, Leaf, witli buds attached ; 106, fruits of E. capUellala, Portland, Vic Mr. A<lams, through ,\. E. 



Kitson, 1904. 



11a. Ijeaf and buds ; 116, fruits. Sandy rise.s, Narracooi'tc, Soutli Australia (W. Gill, 5/01). 



12a. Leaf; 126, rugose buds, simulating J?. ai!/)i/ia ; 12c, fruits, Grampians, Victoria, 2,000 feet. (PI. B. 

 Williamson.) 



