1897.] Proceedings of Scientifie Societies. 475 
Grisebach and now to 500 by resident botanists there, an estimate con- 
firmed by Mr. Gilbert. Probably no other equal area produced half 
that number. Among reasons which account for this are the warm 
latitude of Jamaica, its south shore sheltered from coolor breezes by a 
mountain-wall, its mountains themselves rising to 7,000 feet and reach- 
ing into a cool temperate climate, and its great variation in moisture, 
with daily rains in the mountains and sometimes but twice in six 
months on the plain. Mr, Gilbert described in particular his experi- 
ences with the tree-ferns reached by a long journey on foot, high in 
the Blue Mountains, there forming unmixed groves, their stems supply- 
ing the only wood readily obtainable. One, Alsophila armata, reaches 
50 feet in height, though its slender stem is but a few inches in diameter. 
No class of ferns is as yet so poorly described, as the tree-ferns ; descrip- 
tion should be from the living specimen and at the locality ; the only 
such in English are those in Thwaites’ Flora of Ceylon. Jamaica is 
remarkable in particular for its numerous Filmy Ferns, 26 species 
(out of 280 known); these are all in the three eastern parishes. In 
the east part Blochnum occidentalis is the common fern of the road- 
sides; Polypodium reptans was seen everywhere, now growing erect ; 
one bank 30 x 25 feet was completely covered with Gleichenia pectin- 
acea. The great number of endemic species is surprising ; as if the 
work of differentiation had gone on there with greater activity and 
vital power than anywhere else in the world; every genus in Jamaica 
shows one or more endemic species. 
Mr. Gilbert closed by exhibiting specimens of three new species from 
Jamaica, belonging to Asplenium, Dryopteris and Polypodium, and also- 
of a number of rare species as Entomosora campbellii, Gymnogramma 
schizophylla and Adiautum candollei. His paper was discussed by 
President Brown, Prof. Underwood and Dr. Rusby, the latter referring 
to the uses made of tree-ferns in New Zealand, as compared with the 
use for timber and for posts in Jamaica.—Epwarp S. BURGESS, Secre- 
tary. 
The Chicago Academy of Sciences.—The spring course of 
lectures for 1897 were as follows: March 12. Amelia Weed Holbrook, 
“ The Antiquity of (so-called) Modern Inventions.” March 19. Alja 
Robinson Crook, Ph. D., Professor of Mineralogy and Petrology, 
Northwestern Livesey. “ Some Geological Causes of the Scenery of 
Yellowstone National Park.” Illustrated with stereopticon. March 26. 
Frank Collins Baker, B. S. Secretary and Curator, Chicago Academy 
of Sciences. “ The History of Creation as Revealed in the Rocks.” In 
