386 SCIENCE PROGRESS. 



are almost wholly wanting : Silene acaulis, Saxifraga op- 

 positifolia and Oxyria digyna are the nearest approach to 

 this class of plants. 



A catalogue of the phanerogamic plants of Madeira and 

 Porto Santo (26), not included in the unfortunate Lowe's 

 unfinished flora of Madeira and the neighbouring islands, 

 will be found useful, though it only causes us to lament the 

 more the untimely end of that author. This catalogue con- 

 tains naturalised plants and a few notable cultivated ones, 

 with remarks on the local distribution of the indigenous 

 species, many of which are exceedingly rare. The following 

 are described as new : — 



Koniga arenaria, Scrophularia Moniziana, S. JoJin- 

 souiana, S. maderensis, S. oblonga (name only), Romulea 

 juncea, Tinantia fallax, Potamogeton cuprifolius, P. Machi- 

 canus, Phalaris altissima, and Sesleria elegans. 



The Canary Islands have furnished facts and figures for 

 the phytogeographer from almost the earliest investigations 

 of the distribution and migration of plants. Humboldt and 

 other fathers of the science drew largely at this fountain ; 

 and their labours together with Webb and Berthelot's great 

 descriptive work might have been considered exhaustive, 

 yet Dr. Christ (27) has collected data for one of the most 

 interesting of recent essays on geographical botany. Dr. 

 Christ's work is the result of personal observations, and it 

 is very much more than a statistical exposition of the 

 components of the Mora. Biological phenomena receive due 

 attention, as is exemplified by the discriminating manner in 

 which he describes the vegetation as distinguished from the 

 flora. This work may be profitably studied in connection 

 with Dr. Balfour's flora of Socotra (28), in which the author 

 draws some striking comparisons of the relationships 

 between the floras of these two distant insular regions. 

 Primarily, Dr. Christ insists upon a close relationship between 

 the floras of the Azores, Madeira, the Canaries, and the Cape 

 Verd Islands, and treats them as parts of an intimately con- 

 nected whole. Apart from the last, there is no doubt that 

 the predominating elements are much the same in these four 

 groups of islands, which are scattered through twenty-five 

 degrees of latitude from 15° to 40°. But although there is 



