Mabch 20, 1903.] 



SCIENCE. 



461 



to the same species wliicli has, therefore, 

 been designated as Osmundites sMdega- 

 tensis. From the material now at hand it 

 is possible to effect a complete restoration 

 of the plant with the exception of details 

 relating to the sporangia, but as these 

 structures differ but little in the Osmunda- 

 cese, it would be possible to complete even 

 this detail in a general way, from existing 

 types. A close comparison with existing 

 representatives of this family shows that 

 it approaches the type of Todea in certain 

 details of the phloem structure, as also in 

 the absence of an endodermal layer. In 

 all other respects it closely approaches the 

 type of Osmunda, td which it is no doubt 

 most closely related. A fact of very spe- 

 cial interest is derived from a close com- 

 parison of the relative dimensions of the 

 various structural regions and organs, from 

 which it appears that the fossil must have 

 been at least eight times larger than the 

 modern Osmundas such as 0. claytoniana 

 or 0. cinnamomea, and, with respect to the 

 individual stem, much larger than Todea 

 tarbara. The general conclusions which 

 these facts seem to indicate are that Os- 

 mundites represents a transitional form 

 from which, or from a point near which, 

 divergent lines of development arose, lead- 

 ing to the type of Todea on the one hand, 

 and to the type of Osmunda on the other. 

 It would also seem that Osmundites must 

 have represented a period when the indi- 

 vidual members of the family were much 

 larger that at present, the existing species 

 indicating, in their small size and dimin- 

 ished numbers, a tendency toward oblitera- 

 tion of this branch. The paper was fully 

 illustrated by lantern slides. 



Ecological Conditions of Plant Growth in 

 the Isle of Pines: Professor "W. W. 

 EowLEE, Cornell University. 

 The Isle of Pines has an area of nearly 



a thousand square miles. It is about one 



fifth as large as Jamaica and is as large as 

 all the other islands that immediately sur- 

 round Cuba would be if put together. It 

 lies about thirty miles south of western 

 Cuba, from which it is separated by a very 

 shallow archipelago, the islands of which 

 are small coral keys covered, for the most 

 part, with a dense growth of mangrove. 

 The island lies on the southern verge of 

 the plateau, the northern part of which is 

 the island of Cuba. 



The northern and larger part of the 

 island consists of a rolling table-land, in 

 its highest parts scarcely more than 300 

 feet above tide. The most conspicuous 

 physiographic features of this part of the 

 island are the mountains which rise ab- 

 ruptly in isolated masses to a height of 

 from 500 to 1,600 feet. The principal 

 ones are Sierra Canada, Sierra Caballos 

 and Sierra Casas. 



The flora of the island, taken as a whole, 

 is xerophytic in its tendency. Upon the 

 mountains this tendency manifests itself 

 most strikingly. Not only do plants grow 

 upon the naked rocks, but many plants, 

 such as bromelias, orchids and aroids, grow 

 upon the trees and shrubs without any 

 direct connection with terra firma. Among 

 the trees here were species of Clusia, Ficus 

 and Cecropia, as well as others not identi- 

 fied. On the rocks mingled with them 

 were Plumerias, Biliergias, Fourcroyas and 

 cacti in great profusion. Palms were 

 abundant, particularly on the perpendic- 

 ular faces of the mountains, and were kept 

 in constant motion by the sea breeze. 



The flora of the mountains is very dif- 

 ferent from that of the plains, and 

 strangely enough the pines are conflned 

 to the plains. To the ecologist the moun- 

 tains afford a most interesting study, and 

 there also remains much to be done before 

 anything like a satisfactory list of the spe- 

 cies can be written. The island is com- 

 pletely surrounded by a mangrove zone. 



