Pennsylvania for Session 1897-98. 117 
Mr. C. S. Shaw gave a communication on “ The Ginger 
Beer Plant.” The complex and symbiotic nature of the 
organisms known under the above popular name, their nutri- 
tive relations and their action on the liquid in which they grow 
were described. Naked eye specimens and microscopic 
preparations of the symbiotic growth were shown. 
Dr. Macfarlane commented on exhibitions of living plants 
made from the greenhouses of Mr. Craig and Mr. Harris. 
March 18. Dr. Miller in the chair. Miss Vansant read a 
paper on “ The Ferns of Bucks County,” in which thirty-eight 
species and distinct varieties were described and the most 
noteworthy localities referred to. 
Dr. H. C. Porter spoke on “ Structural Relations of Ferns 
and Their Allies,” and discussed the probable relation of 
eusporangiate to leptosporangiate types. 
Mr. T. Chalkley Palmer gave an account of his studies on 
the genus /svetes. After discussing the nature of the ligule 
and the deposit of silicon over the spore-wall, he suggested 
that the sculpturing of the macrospores is a device for lodging 
the microspores in their immediate neighborhood. In the 
vicinity of Philadelphia are found Jsoetes riparia, I. Engel- 
mannt and I. echinospora var Brauniz. Specimens and draw- 
ings of these were exhibited. 
An extremely rich collection of living ferns was shown from 
the plant houses of Messrs. Dreer, while Mr. Le Boutillier 
exhibited several interesting orchids. 
April z. Dr. Miller in the chair. Professor Macfarlane 
spoke on “The Natural History of Orchids.” He divided 
them into three types, (a) soil growers, (4) epiphytic growers 
(c) saprophytic growers. The structure and distribution of 
each of these, the comparative morphology of the flower, the 
effects of hybridisation and the characters of the hybrid off- 
spring were reviewed. 
Mr. Le Boutillier followed with an account of trips in search 
of orchids made to Yucatan, Mexico and Jamaica, and illus- 
trated his remarks with a beautiful series of lantern slides 
