Pen?isylvania for Sessio7i i8^y—g8. 1 1 7 



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 iS. 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 ot 

 eusporangiate to leptosporangiate types. 



Mr. T. Chalkley Palmer gave an account of his studies on 

 the genus Isoetes. 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 Isoetes riparia, I. Engel- 

 nianni and /. echiiiospora var Braunii. 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 I. Dr. Miller in the chair. Professor Macfarlane 

 spoke on " The Natural History of Orchids." He divided 

 them into three types, {a) soil growers, {b) 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 



