_Preponderance of Ferns in the Mascarene Flora._--A striking character of the flora of these smaller Mascarene islands is the great preponderance of ferns, and next to them of orchideae. The following figures are taken from {446} Mr. Baker's _Flora_ for Mauritius and the Seychelles, and from an estimate by M. Frappier of the flora of Bourbon given in Maillard's volume already quoted:-- _Mauritius, &c._ _Bourbon._ Ferns 168 Ferns 240 Orchideae 79 Orchideae 120 Gramineae 69 Gramineae 60 Cyperaceae 62 Compositae 60 Rubiaceae 57 Leguminosae 36 Euphorbiaceae 45 Rubiaceae 24 Compositae 43 Cyperaceae 24 Leguminosae 41 Euphorbiaceae 18 The cause of the great preponderance of ferns in oceanic islands has already been discussed in my book on _Tropical Nature_; and we have seen that Mauritius, Bourbon, and Rodriguez must be classed as such, though from their proximity to Madagascar they have to be considered as satellites to that great island. The abundance of orchids, the reverse of what occurs in remoter oceanic islands, may be in part due to analogous causes. Their usually minute and abundant seeds would be as easily carried by the wind as the spores of ferns, and their frequent epiphytic habit affords them an endless variety of stations on which to vegetate, and at the same time removes them in a great measure from the competition of other plants. When, therefore, the climate is sufficiently moist and equable, and there is a luxuriant forest vegetation, we may expect to find orchids plentiful on such tropical islands as possess an abundance of insects adapted to fertilise them, and which are not too far removed from other lands or continents from which their seeds might be conveyed.