INTRODUCTION TO THE REPORTS ON INSULAR FLORAS. 3 



when at least a third of the plants' bad not been described, and the existing literature 

 was very much scattered, has been the basis of all subsequent inquiries in the same 

 direction, and later discoveries go towards completing the pictures there outlined. The 

 section devoted to the consideration of the Antarctic or Alpine element of the Australian 

 Flora is of special interest in connection with the present work. 



The only other work by Sir Joseph Hooker demanding notice in this place is the 

 Lecture on Insular Floras delivered by him before the British Association in 1866. In 

 this the general features of the vegetation of remote oceanic islands are explained, and the 

 special characteristics and affinities of the floras of various islands and groups described. 

 Commencing with the Madeiran group, the author continues with the Canaries, Azores, 

 St Helena, Ascension, concluding with Kerguelen Island. He then proceeds to discuss the 

 hypotheses that have been invented by naturalists to account for the presence of continental 

 plants in oceanic islands, and for those various differences between insular and continental 

 Floras previously indicated. 



Watson, H. C. — The author of the Cybele Britannica, and other works on the dis- 

 tribution of British plants, was so great an originator in this special branch of study that 

 his name will endure as long as phytogeography is cultivated. Not the least among the 

 merits of his works is the careful classification of British plants, based upon their claims to 

 be regarded as aboriginally native, and upon the extent to which assumed naturalised 

 species had established themselves. He was the first, we believe, tg distinguish fully the ' 

 introduced from the indigenous element of a flora ; and the first to recognise the different 

 " types of distribution " represented in the vegetation of a country. 



Forbes, E. — Although this writer's contributions to the literature of phytogeography 

 are, like Watson's, limited almost exclusively to British plants, his theories are of general 

 application. His essay on the Geological Relations of tbe Fauna and Flora of the British 

 Isles was the forerunner of all speculations on the migration of plants in relation to 

 a;eolo2:ical changes. 



De Candolle, A. — The Geographic Botanique Raisonnee is a work remarkable for the 

 skilful co-ordination of a vast array of facts, and the logical precision of the arguments ; 

 but so little was known of Insular Floras at that date that it was impossible for the 

 author to enlarge upon the subject. A chapter (p. 1278) is devoted to the question 

 whether islands possess a smaller number of species on the same area than continents, 

 which is substantially answered in the affirmative, save for such as are most favourably 

 situated. 



Wallace, A. R. — In his Island Life, Wallace specially deals with the distribution and 

 the origin of the plants and animals inhabiting islands. He classifies islands according to 

 their " two distinct modes of origin," continental and oceanic. The latter he assumes have 



