171 



horizontal aud vertical distribution, tlie extent of variation as well as the 

 external circumstances which favour its production, would be a contribution of 

 the highest value to morphological science.* In fact, it is indispensable to real 

 progress. Deductions drawn from isolated examples can seldom be made 

 available for general laws. We have, for example, no evidence to show that 

 the eai-ly trifoliate-leaved state of Melicojje siinplex is any proof that the 

 plant has " passed through " other forms whether extinct or recent, than we 

 have that it should be considered indicative of future development. This, 

 however, must not be construed into a positive opinion on the theory involved. 



To revert for a moment to the subject of plant variation in the Noi'thern 

 district : it is worthy of remark that all the species of Veronica belong, with 

 a solitary exception, to the section with dorsally compressed caj)sules, but it 

 could not possibly be said that in this district "they appear to present a 

 graduated scale of forms." On the contrary, the amount of variation is 

 extremely limited, and the intermediate forms must be sought for in the 

 southern parts of the colony. 



But, on the other hand, the northern genus Alseuosmia presents in its 

 four or five recognized forms, an amount of variation in habit and foliation 

 fidly equal to that of any similar number of the southern Veronicas ; and, so 

 far as appears at present, this variation is not affected by habitat. 



I have the pleasing duty of tendering my thanks to Mr. Buchanan, for a 

 large amount of information kindly afforded by him ; without his valued aid 

 the appended lists of corrections and additions would have been much less 

 complete ; also to Mr. Robert Mair and Mr. T. F. Cheeseman, for copious lists 

 of the plants observed by them at "Whangarei ; and especially to Mr. Colenso, 

 for much valued criticism and information afforded by him during a lengthened 

 coriespondence. 



In the following notes I hold myself personally responsible for authenticity 

 in all cases not otherwise specified. 



Note. — Particulars of the Naturalized Plants of the Northern District 

 will be found in the Iransactions of the New Zealand Institute, Yol. ii., p. 131. 

 The North Cape District and the southern portion of the Whangarei district 

 of that paper, form the area now treated of. 



* A knowledge of the aberrant forma of the outlying islands, the Kermadec and 

 Auckland groups, etc. , would possess special value. 



