270 MR. T. F. CHEESEMAN ON 
This will leave 235 species which without any doubt must be regarded as truly 
indigenous. 
Examining the distribution of these 235 plants in detail, it appears that 167 are also 
found in Tahiti or some part of the Society Islands ; while 129 occur in the Tongan 
Islands. 103 are common to both groups. These figures show that the flora is most 
nearly allied to that of Tahiti. A further proof of this is afforded by the presence of a 
species of Fitchia and another of Sclerotheca, genera hitherto believed to be peculiar to 
the Society Islands. At the same time, it should be mentioned that the preponderance 
of Tahitian species over Tongan is mainly due to the small number of Ferns recorded from 
Tonga, Hemsley’s and Burkill’s lists containing only 37 for the whole group as against 
67 for Rarotonga. Most of the Rarotongan Ferns, in addition to being found in Tahiti, 
occur in Samoa, Fiji, and other parts of Western Polynesia; and if this is taken into 
account the preponderance of eastern plants is very slight indeed. It must be remembered 
that the vegetation of the Tongan, Cook, and Society Islands is only part of a Polynesian 
Flora which, in its main features, extends from the Solomon Islands to Easter Island 
and from Hawaii to Tongatabu. 
My visit to Rarotonga extended over the months of May, June, and July—the time 
of the year best suited for investigating the flora. As I have travelled round the 
island, ascended all the mountains, and practically visited every portion of it, it may be 
concluded that my collections give a tolerably complete idea of the vegetation. There 
are, however, some half-dozen species which were not obtained in flower or fruit, and 
which consequently cannot be identified ; and there are also a few species of Orchideze 
and Scitaminew of which only withered stems could be obtained at the time of my visit. 
Additions will doubtless be made, but I do not think that they will be very numerous. 
Before passing on to the systematic catalogue, I wish to tender my most sincere 
thanks to the Bentham Trustees for contributing drawings of the new species. I have 
also to express my indebtedness to Sir W. T. Thiselton-Dyer, the Director of the Royal 
Botanic Gardens, Kew, for the kind assistance and encouragement he has given 
throughout, and to Mr. W. B. Hemsley for his unwearied kindness in examining and 
comparing my specimens and in superintending the preparation of the Plates. I have 
also to express my acknowledgments to Prof. E. Hackel, Dr. Stapf, Messrs. C. B. Clarke, 
C. H. Wright, and R. A. Rolfe, all of whom have rendered valuable aid. 
