My life : a record of events and opinions - Wallace-online.org

266 MY LIFEdependent on, that of plants, that a considerationof the latter is essential to any broad views as to thedistribution of life upon the earth, while they throwunexpected light upon these exceptional means ofdispersal which, because they are exceptional, areoften of paramount importance in leading to theproduction of new species and in thus determiningthe nature of insular floras and faunas.Having no knowledge of scientific botany, itneeded some courage, or, as some may think, presumption,to deal with this aspect of the problem;but, on the other hand, I had long been excessivelyfond of plants, and was always interested in their distribution.The subject, too, was easier to deal with,on account of the much more complete knowledgeof the detailed distribution of plants than of animals,and also because their classification was in a moreadvanced and stable condition. Again, some of themost interesting of the islands of the globe had beencarefully studied botanically by such eminentbotanists as Sir Joseph Hooker, for the Galapagos,New Zealand, Tasmania, and the Antarctic islands ;Mr. H. C. Watson for the Azores ; Mr. J. G. Bakerfor Mauritius and other Mascarene islands ; whilethere were floras by competent botanists of the SandwichIslands, Bermuda, and St. Helena. With suchexcellent material, and with the further assistanceof Sir Joseph Hooker's invaluable essays on therelations of the southern and northern floras, I feltthat my work would be mainly of a statistical nature,asinterpreted by those general principles of organicevolution which were my especial study.But I also found it necessary to deal with a totallydistinct branch of science—recent changes of climateas dependent on changes of the earth's surface,