ON THE FLORA. OF THK PHILIPPINE ISLANDS. 283 



Fig. 7. Section of thallus of Psoroma hypnorum, highly magnified, showing the 

 gonidia enclosed in the cellules of the cellulose medulla, la. Sepa- 

 rated gonidia enclosed in the cellules, magnified 275 diameters. 

 After Nylander. 



Fig. 8. Isidiose globules of Collema furvum in different stages of growth, 

 showing that the gonimia originate from the very first in the isidia 

 themselves. 8a. A syngonimium fully developed, magnified. 



On the Flora of the Philippine Islands, and its probable Deri- 

 vation. By E. A. EoLira, Herbarium, Eoyal Gardens, Kew . 

 (Communicated by Prof. Oliver, F.E.S., F.L.S.) 

 [Read 1st May, 1884.] 

 (Plate X.) 

 The Philippines are a large group of islands situated to the north- 

 east of the great bank (for the most part less than 50 fathoms 

 below the surface) which stretches out from the Siamese and 

 Malayan peninsulas to Sumatra, Java, and Borneo. They extend 

 over nine degrees of latitude and fourteen of longitude, and much 

 of their present configuration is directly due to volcanic agency. 

 The northern island of Luzon is the largest of the group, being 

 about the size of Ireland, though of a very different shape. 

 Mindanao, the southern island, is of almost equal extent. Negros, 

 Samar, Panay, Mindoro, and Palawan are each about one eighth 

 to a tenth as large as Luzon ; Leyte, Cebu, Bohol, and Mashate 

 are still smaller ; while a large number, gradually decreasing in 

 size, are scattered about in various directions. 



The Philippines are for the most part surrounded by deep sea, 

 but there are several submerged banks, indicating connections 

 with neighbouring islands at some former period. One of these 

 banks stretches away from the northern point of Luzon in the di- 

 rection of Formosa, and on it are situated two small groups of islets 

 —the Bashees and the Babuyanes. North of these a deep channel 

 extends to the southern point of Formosa. From the south- 

 western corner of Luzon there is a very distinct connection with 

 the northern point of Borneo, by way of Mindoro, Busuanga, the 

 long island of Palawan, and the small island of Balabac; the 

 deepest channel along this bank being the Mindoro Straits, 

 which separate Mindoro from Busuanga. The Sulu archipelago 

 stretches from the southern point of Mindanao to the north- 

 western point of Borneo. This bank is separated from the former 

 by the Sulu Sea- a deep sea, much of it reaching to over two 



