492 Transactions. — Miscellaneous. 



very limited few indeed — to be able to generalize and build up into a homo- 

 geneous whole the heterogeneous materials collected by the multitude. 

 We can all help to accumulate these materials together, leaving it to the 

 master-minds of science to use the fruits of our labour. 



I have very briefly attempted to show what are the principal theories 

 enunciated to account for our flora. I now propose to exa.mine some of the 

 modes by which plants become distributed, particularly noticing their appli- 

 cation to New Zealand plants, and further, to show a little more in detail 

 than Mr. Wallace could afford to do in a general work, the relations of our 

 flora to that of Australia. 



In examining such a problem as the distribution of plants, it is manifest 

 that one of the most important considerations to be taken into account is 

 their mode of dispersal, and chiefly, of course, the mode of dispersal of their 

 seeds. Some plants, such as the strawberry, no doubt have the power of 

 spreading themselves over wide areas by means of their long trailing shoots, 

 as we see this plant doing at the present day wherever it has been intro- 

 duced. But even the strawberry appears to be dispersed much more by its 

 seeds than its suckers, and it is the seed therefore which must be considered 

 chiefly. The most important agents concerned in the dispersal of seeds 

 are (1) the wind ; (2) birds or other animals ; and (3) ocean currents. 

 Besides these, icebergs may have been the means of bringing some plants 

 to our shores ; rivers have certainly distributed them from higher to lower 

 levels ; and lastly, human agency has been an efficient cause in late years. 

 But for the first of these extra causes — viz., icebergs — we have no data 

 beyond very general ones to go upon, and the other two have little bearing 

 on the wide question of the origin of the flora. 



(1.) The wind is certainly a most efficient agent in the dispersal of seeds, 

 and many plants have their seeds specially adapted for the purpose of being 

 so distributed. The order Compositae shows the greatest specialization in 

 this respect, the calyx-hmb being modified in a large proportion of the 

 species mto a pappus, which acts as a parachute. The order is the 

 largest in the New Zealand flora, numbering 24 genera and including 

 167 species, but from its wide-spread means of dispersion is of less value 

 than less highly differentiated orders. The majority of our plants 

 of this order are either Australian or are allied to Australian forms, 

 a few being of very wide distribution. Another contrivance for wind- 

 dispersion is found in the persistence of the stigma in the form of 

 long feathery awns on the achenes. This is represented in the genus 

 Clematis, a genus occurring in all temperate climates, and of which the 

 New Zealand species, as well as the Australian, are all endemic. Its 

 origin here is therefore an open question. The genus Atherosperma, belong- 



