The mountain-flora of the Tahitian region, as illustrated by the non-endemic genera.—Derived chiefly from high southern latitudes.—Weinmannia, Coprosma, Vaccinium, Astelia, Coriaria, Cyathodes, Nertera depressa, Luzula campestris.—The mountain flora of Rarotonga.—The mountain-flora of the Fijian region, as illustrated by the non-endemic genera.—Weinmannia, Lagenophora, Coprosma, Astelia, Vaccinium, Nertera depressa.—The Fijian Coniferæ.—Dammara, Podocarpus, Dacrydium.—Not belonging to the present era of dispersal.—The age of dispersal of the Coniferæ in the Pacific.—Earlier than the age of Compositæ and Lobeliaceæ.—The first in the Mesozoic period.—The last in the Tertiary period.—Summary.
The Mountain-Flora of the Tahitian Region as Illustrated by the Non-Endemic Genera
This floral region of the Pacific corresponds with the limits of Eastern Polynesia, and includes not only the Tahitian group proper, but also the Cook, Austral, Paumotuan, and Marquesan groups. It is only, however, in Tahiti, the peaks of which rise to over 7,000 feet above the sea, that we should expect to find such a mountain-flora, since the islands of the other groups are much lower, the highest of them in the Marquesan group barely exceeding 4,000 feet. Yet even in Tahiti it is not possible to speak of a mountain-flora in the sense that we attach to it in Hawaii. The elevated area of its interior is, as described in [Chapter XIX.], relatively very small; whilst, as Drake del Castillo points out, the conditions presented by the steep mountain-slopes rarely afford a hold for trees of any size, ferns often predominating in the higher levels. Still, we can observe the traces of such a flora, and it is in this sense only that the term “mountain-genera” is used in relation with this group.
Mountain-Genera of the Tahitian or East Polynesian Region.
- Weinmannia, Saxifragaceæ, from New Zealand.
- Coprosma, Rubiaceæ, from New Zealand.
- Vaccinium, Vacciniaceæ, from the northern hemisphere.
- Astelia, Liliaceæ, from New Zealand.
all species endemic.
- Coriaria, Coriariaceæ, from New Zealand
- Cyathodes, Epacridaceæ, from New Zealand
some species endemic
- Nertera depressa, Rubiaceæ, a species of the Antarctic flora.
- Luzula campestris, Juncaceæ, from the northern hemisphere.
The Tahitian non-endemic mountain-genera, though scanty in number, are of considerable interest to the student of plant-dispersal. Among those possessing only species that are confined to Eastern Polynesia, genera that would be regarded as belonging to a past era of dispersal, Weinmannia, Coprosma, Vaccinium, and Astelia may be mentioned.