GEOGRAPHY OF PLANTS. 5 1 



any settlement. Of course, the progress of colonization has introduced a 

 vast number of European weeds, some of which, especially the thistles, bid 

 fair soon to supplant weeds of natural growth, and in a few years the local 

 botanist will be puzzled as to the claims of many plants, whether indige- 

 nous or naturalized. The flora of New Zealand contrasts remarkably with 

 that of the larger island, for out of the 730 flowering plants described by 

 Dr. Hooker, 223 are common to other countries, and 60 are common to 

 Europe. Of the 113 species found at Norfolk Island, 61 are peculiar to 

 that island, 52 common to other countries, and 8 also natives of Europe. 

 The little island of Tristan Da Cunha, so well explored by the late 

 Captain Carmichael, contains 32 species of flowering plants, 26 of which 

 are found nowhere else. 



We have next tables to show the proportion, by families, of species 

 common to widely separated countries. The facts are similar to those 

 just stated, but given more in detail, and illustrated by more nume- 

 rous examples. Then follow tables showing the proportion, by fami- 

 lies, of species dispersed over more than two regions, and the mean 

 area of species considered in reference to the nature of their habitats, 

 whether aquatic, moist, or dry ; relative to their duration, whether annual, 

 biennial, perennial, &c. ; their degree of lignification, whether trees, shrubs, 

 or suffrutices ; and lastly, relative to the nature of their seeds, whether 

 the fruit or seed be winged or fleshy, whether the seeds be numerous or 

 few, small or of large size, soon perishable or capable of long existence in 

 a dormant state. It is impossible in this hasty sketch to do justice to the 

 care with which these and other details are worked out. We can only 

 mention a few of the results. With respect to habitat, it appears that 17 

 per cent, of submerged or floating flowering plants are common to more than 

 two regions, 9 per cent, of marsh plants, 7 per cent, of the plants of wet 

 ground (not strictly marshes), 10 per cent, of maritime plants, and 7-10 

 per cent, of parasitical plants. Out of 389 purely parasitic plants noticed, 

 only three are found in more than two regions. The half parasites, such as 

 Orohanche, Monotropa, and Cuscuta are more dispersed, 8 per cent, being 

 found in more than two regions. Of families chiefly consisting of annual 

 species, 7 per cent, occur in more than two regions ; of perennial herbaceous 

 families, 5 per cent. ; and of those composed of trees and shrubs, less than 

 2 per cent. A considerable number of arborescent plants are limited to 

 one or two regions ; out of 2,321 species enumerated, only 43 exceeding 

 those limits. Out of 292 coniferous trees, 12 are widely dispersed, a large 

 per centage when compared with most other ligneous families. One would 



