Floristik, Geographie, Horticultur etc. 381 



presence ot certain Coniferae {Danimara, Podocarpus , and Dacrydium) 

 which are absent from Hawaii and Tahiti. The author regards 

 these as belonging to an Age of Coniferae which prevailed in the 

 Fijian group during the Mesozoic Period, when the Hawaiian 

 and Tahitian groups of islands did not exist, therefore this age 

 preceded that of the Compositae. During the Tertiary submergence 

 of the Fijian area suggested above, these Coniferae are regarded as 

 having maintained their hold on a few of the mountain-peaks which 

 were not submerged. A later period in the flora of the Pacific 

 islands is thus defined : "The following epoch, which ends only 

 with the arrival of man, is characterised by the genera found outside 

 the group; and here different degrees of antiquity are indicated 

 according as the genus is represented whoUy or in part by peculiar 

 species, or contains only species found in other regions." The large 

 mountain mass of Hawaii is specially rieh in endemic species, 

 many of them belonging to genera characteristic of the Antarctic or 

 New Zealand, with some representatives of American affinity, 

 more than half, however, belong to genera (e.g. Ranunculus , Rubus, 

 Vaccinimn and Plantago) found in all temperate parts of the world , 

 and in the temperate zone of tropical mountains. 



In a chapter on Seed Dispersal and Geological Time, a useful 

 summary of the author's views is given. The glacial period of the 

 Northern Hemisphere is here placed subsequent to the age of 

 Coniferae and that of Compositae, and its effect was to drive the 

 tropical flora into "the tropical Western Pacific," only to be set 

 free after the cold period had passed away. Then came the later 

 epoch of Indo-Malayan plants. The glacial period is also invoked 

 to explain the shifting of the source of Hawaiian plants from 

 America to Asia. Another agency is emphasised thus: "The 

 Suspension to a great extent of the agencies of plantdispersal in the 

 Pacific in later times is connected with a general principle affecting 

 the whole plant-world. With the secular dr3ing up of the globe the 

 differentiation of climate, bird, and plant have gone on together, tho 

 ränge of the bird being mainly controUed by the climate, and 

 the ränge of the plant being largely dependent on the bird." 



Two chapters are devoted to the mangroves, with their peculiar 

 viviparous seeds, which germinate on the tree, the seedling falling 

 to root at once in the mud below, or to be carried off b}^ the rising 

 tide. This vivipary is generally regarded as a kind of cul-de-sac, 

 or specialised from representing the other extreme from seeds which 

 fall from the parcnt in an immature condition unfit to germinate 

 until they have lain on the ground for some time. Mr. Gupp}- does 

 not regard vivipary as a highly evolved process, but as a remnant 

 of a condition which existed commonly in early plants at a time 

 when the earth's atmosphere was humid and warm. 



The chapter on the West Coast of South America deals 

 mainly with the distribution of Mangroves, and a wider ränge in 

 past times is suggested. Observations are also giv^en to support the 

 author's view that America acted as a distributing centre for 

 Pacific islands. 



Statistical details of observations are given in an Appendix of 

 SO pages. The small number of illustrations is noteworthy in a book 

 published at the present time when these are so much used in 

 scientific works. W. G. Smith (Leeds). 



