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Exhibits: 1. Stems of Xanuthoxylum, Euonymus, Liquidambar 
and Quercus. 2. Microscopic preparations and plates. 
{15. COMPARATIVE ANATOMY OF THE PULVINUS OF VARIOUS 
LEAF PETIOLES. By Bertha Dow. 
The pulvinus: is the organ by which the so-called sleep 
motions of leaves are brought about. The investigation is 
intended to show to what extent this organ is necessary. 
Many leaves change their positions day and night, which have 
the pulvinus very slightly developed. 
Exhibits: 1. Plant with fully developed pulvinus and plant 
without. it. 2. Microscopic preparations showing cellular 
structure of the organ and its adaptation to motion in Arachis, 
Wistarza and Oxalis. 
116. THE COMPARATIVE ANATOMY OF COREMA ALBA AND 
COREMA CONRADII. By Marion McEwen. 
The genus Corema (natural order Empetracez) includes only 
these two species, the first native of Portugal and the Azores, 
the second of Eastern North America, extending from New 
Jersey to Newfoundland. The present study was undertaken 
to ascertain how far their anatomic characters support their 
generally accepted relationship, it having been suggested that 
they might represent two different genera. The investigation 
showed that the accepted notion is correct. 
Exhibits: 1. Examples of the two species, mounted as her- 
barium specimens. 2. Microscopic preparations with draw- 
ings, showing leaf and epidermis sections. 
117. STUDY OF SCHWENDENER’S MECHANICAL SYSTEM IN THE 
ANATOMY OF PLANTS. By Alexandrina Taylor. 
The work illustrates the theory that the first function of thick- 
walled or woody tissues of plants is that of support and not 
that of water conduction. It shows that the principles 
applied by the engineer to bridges and other structures where 
economy of material is required are the same as those followed 
in plant development. 
Exhibits: Microscopic preparations with drawings of cross- 
sections of the stems of the following monocotyledonous 
plants: Indian Corn, Lily, /Jwucus, Grasses. 
