Pennsylvanta for Sessions IgoI—1g03. Ixxyv 
Mayr. Dr. Miller, President, in the chair. Miss Marion 
Mackenzie gave her monthly Phyto-phenological Report, 
from which it appeared that the season was still an advanced 
one for vegetation. A comparison of the flowering periods 
of Dicentra cucullaria, Cornus florida, Viola pubescens, etc., 
showed that these and other species were from a week to ten 
days ahead of their average blooming period. 
In continuation of the above report, Dr. Macfarlane then 
spoke on “Recent Climatic Conditions in Relation to Plant 
Life.” He stated that owing to the early unfolding of 
buds up to April 3d, the sudden frost of the evening of 
April 4th-5th did considerable damage. The buds of 
Ginkgo were more or less hurt, as were also those of Lilac, 
but the plant that suffered most was Polygonum Steboldiu, 
the shoots of which were quite destroyed where exposed to 
full frost effects. The flower buds of Judas tree were in 
many cases badly hurt. 
Dr. Henry Leffmann then spoke on “The Diatoms of 
Agar-Agar.” The Algal product Agar-Agar is a substance 
of the fruit-jelly rather than the animal or nitrogenous-jelly 
type. From its origin the commercial article seems pretty 
often to contain diatoms, the commonest of which is Arach- 
nodiscus Ehrenbergu, though Cocconets is also represented. 
The agar is secured along the Pacific coast where these 
diatoms also occur. Since agar is now being used as thick- 
ening jelly, the speaker believed that the occasional occur- 
rence of the above diatoms might be an aid in detecting the 
origin of the jelly. 
Dr. Macfarlane then spoke on “Parasitism in Plants 
with Special Reference to that of the Mistletoe and Dod- 
der.” He said that some parasites showed no specific prefer- 
ence in their food supply, and cited Comandra and Cassytha 
as examples. Again in the case of Aphyllon, Epiphegus and 
Conopholis, the parasite restricts its attack wholly to one 
species or genus, and in such cases the parasitic degrada- 
tion becomes increasingly marked and seed production more 
