Pennsylvania for Sessions 1899-1900. XIX 
from the collections of Mr. Le Boutillier and the University 
Botanic Garden. 
Apri 28. Dr. Miller inthe chair. Mr. T. Chalkley Palmer 
communicated “‘ Observations on the Growth and Conjugation 
of Closterium,” in which he described the structure of the 
mature plant, varieties of conjugation and the development of 
the zygospore. 
Dr. S. C. Schmucker, chairman of the Phytophenological 
Committee, distributed recording sheets to the members and 
gave some recent dates for flowering. An interesting discus- 
sion followed. 
The chairman read a letter from Mr. Schumo, in which a 
graphic description was given of the vegetation and vegetable 
products of Guatemala; the luxuriant growth of mosses, 
filmy ferns and palms was specially commented on. 
Exhibitions of plants in flower were made by Mrs. Mary 
Williams and from the University Botanic Garden. 
May 12. Dr. Miller in the chair. Mr. Hugh E. Stone, 
of Doylestown, then gave an instructive lecture on ‘‘ The 
Orchids of Chester County,” in which he compared his finds 
with those recorded by Dr. Darlington in the “‘ Flora Cestrica.” 
The special thanks of the society were awarded the speaker. 
Dr. J. W. Harshberger then described “‘ Aspects of Trop- 
ical Nature in Mexico, with Special Reference to Native 
Dahlias.”’ Hespoke of the more typical plants observed dur- 
ing his stay there. He graphically pictured the varying 
character of the vegetation by aid of lantern slides; and then 
compared the different species and varieties of dahlia as to 
size, habit and color of the flowers. 
Professor Macfarlane gave short notes on a collection of 
plants recently received at the University garden through the 
kindness of Mrs. Mary Williams. These included flowering 
specimens of the Coonti or Compti (Zamia integrifolia), 
Ficus aurea, Isonandra gutta, Hevea braziliensts, etc. 
