INTRODUCTION. lvii 
Pringlea and Lyallia, are confined to the islands under consideration ; two, Plewro- 
phyllum and Stilbocarpa, do not extend beyond the New-Zealand region; six are 
represented only in the American and the Australasian regions; fourteen are of wide, 
mostly of almost universal, distribution, and six of the species are of nearly equally 
wide range. The monotypic Pringlea antiscorbutica has no near ally in the southern 
hemisphere, but it is closely related to the northern genus Cochlearia, differing more 
in habit of growth than in floral structure. And Lyallia is of the same affinity as the 
Andine Pycnophyllum and the Mexican Cerdia. 
As already stated, the Tristan da Cunha group and Amsterdam and St. Paul Islands 
can hardly be included in the antarctic region, unless we make it more extensive in 
New Zealand and in South America, because the bulk of the vegetation consists of 
Phylica nitida and Spartina arundinacea, types of a warmer region; the former, the 
only tree or even shrub larger than the trailing Empetrum, being a Mascarene species, 
and the latter a tall reed, whose nearest ally is a native of eastern temperate South 
America. Not one of the plants enumerated in the foregoing table is recorded from 
the Tristan da Cunha group, and only two, Ranunculus biternatus and Uneinia 
compacta, inhabit Amsterdam or St. Paul Island. On the other hand, several of the 
plants found in the Tristan and Amsterdam groups are common to New Zealand and 
South America. Of the twenty-nine flowering plants known to inhabit the Tristan 
group sixteen are apparently endemic; three are South-American and are not repre- 
sented eastward, while six extend eastward, three reaching New Zealand. Nineteen 
flowering plants are recorded from St. Paul and Amsterdam, eight of which have not 
been found elsewhere, and the distribution of the remainder is similar to that of the 
Tristan da Cunha non-endemic element. Numerically as to species, then, the compo- 
sition of the Tristan and Amsterdam Floras is that of the cold temperate region and 
very similar to that of the islands farther south; but several of these species are quite 
rare, and the conspicuous vegetation, apart from ferns, is almost wholly Phylica and 
Spartina, at least in the Tristan da Cunha group and Amsterdam Island. 
CONCLUDING REMARKS. 
The facts brought together in the preceding pages and in the ‘ Appendix ’* have an 
interest apart from any conclusions arrived at, and whether the views therein put 
forward on the botanical regions of the world meet with acceptance or not, it will be 
generally conceded that although the broad features of the distribution of plants and 
animals are essentially the same, they are by no means identical. 
When it is considered how much more potent and diversified are the means of 
* It may be well to repeat that this is a review of the results of comparatively recent investigations rather 
than an attempt at an exhaustive discussion of the subject. 
BIOL. CENTR.-AMER., Bot. Vol. I., October 1888. h 
