MEETINGS OF SOCIETIES. 85 
theories enunciated to account tor our flora. I now propose to 
examine some of the modes by which plants become distributed, 
particularly noticing their application to New Zealand plants; and 
turther, 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 introduced. But even the strawberry 
appears to be dispersed much more by its seeds than by 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 dis- 
tributed 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 ot being 
so distributed. The order Composite shows the greatest specializa- 
tion in this respect, the calyx-limb being modified in a large pro- 
portion of the species into 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 differen- 
tiated orders. The majority of the 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 ot the stigma in the torm of long feathery 
awns on the achenes. This is represented in the genus Clematis, a 
genus occurring in all temperate climates, and ot which the New 
Zealand species, as well as the Australian, are all endemic. Its 
origin here is therefore an open question. The genus Athevosperma, 
belonging to a specially South American order, is similarly cha- 
racterised, but its occurrence here has no special significance, as 
Australia possesses an endemic species, as well as New Zealand, 
The genera Epilobium and Parsonsia both have tufts of hair on their 
seeds to aid in their dispersal; the former is a very wide-spread 
genus in all temperate regions, and some of its species are common 
to both hemispheres, while the latter is an Asiatic and Australian 
genus. The only other contrivances which aid in the wind- 
dispersal of our New Zealand plants are wings on the truits or 
seeds. These occur, but feebly developed, on the nuts of Fagus, 
and on the seeds of Kuightia, Dammara, and Libocedvus. The first of 
these occurs in both the north and south temperate regions, but 
our and the Australian species are all probably ot antarctic origin. 
The second genus has one New Caledonian representative, and 
