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the hepatic flora changes in a marked. degree. Although the 
number of individuals is no greater than in many northern 
regions and is probably less than in certain alpine or arctic 
localities, the number of species increases greatly. This is true 
particularly of the Lejeuneae and of such genera as Riccardia, 
Frullania, Radula, Porella, and Plagiochila. Our knowledge of 
these genera is still very incomplete indeed, and it is difficult and 
perhaps not profitable to compare the Hepaticae of tropical 
North America with those of other regions. 
The relationship of our tropical flora with that of Africa is 
certainly not close, although a few of our species are found in 
Africa. There is certainly nothing at all comparable with the 
close relationship which exists between our northern flora and 
that of Europe. 
Dr. Evans also discussed the recent studies of the morphology 
of the leafy Hepaticae in regard to (1) regeneration, (2) organs of 
vegetative reproduction, and (3) branching. 
Under the title of ‘‘Notes on the Ricciaceae,’’ Miss Caroline 
C. Haynes exhibited excellent drawings of habit and structure of 
several American species of the genus Riccia. The drawings of 
the surface markings of spores, which have been found of diag- 
nostic value in distinguishing species of Riccia, were especially 
noteworthy. Miss Haynes exhibited also the drawings for the 
plates that accompanied her revision of the genus Sphaerocarpos, 
published in 1910. 
“The Mitten and the Underwood Collections of Hepaticae”’ 
were described by Dr. Marshall A. Howe. The mosses and 
hepatics of the herbarium of William Mitten of Hurstpierpoint, 
England, were purchased by the Garden in 1906. This collection 
ranked among the largest of its kind and was said to contain 
50,000 specimens, of which about one third were Hepaticae. For 
nearly half a century Mr. Mitten received for study and deter- 
mination most of the foreign collections of mosses and hepatics 
that fell into British hands, such as those made by the naturalists 
of the famous Challenger Expedition, the Transit of Venus 
Expeditions, the Voyage of H. M. S. Herald, by Bishop Hanning- 
ton in Central Africa and by various other British explorers and 
