(120) 
occur locally, and the characteristics of the several groups 
as mentioned under the synoptic collection also apply here. 
(d) The Plant Photograph Exhibit. A series of over 200 
enlarged photographs, illustrating plant societies, habit- 
characters, flower-characters, and fruit-characters of the 
higher plants, as well as habit and structural characters of 
some of the larger algae and fungi, is displayed in frames 
fastened to the walls of the systematic museum. As far 
as practicable, they have been placed near the cases con- 
taining representatives of the species illustrated. The 
photographs are II x 14 inches in size and are mounted in 
glazed frames, some frames containing 4 and others 6 
photographs. 
3. THE MUSEUM OF FOSSIL BOTANY 
This collection, installed in the basement, is designed to 
show the successive stages of evolution through which the 
ancestors of our living flora have passed since the time of 
the first appearance of plant life on the earth, as far as the 
remains of extinct plants have been preserved. The 
general arrangement adopted is therefore based upon the 
sequence of the geological time divisions: Eozoic, Paleozoic, 
Mesozoic, and Neozoic, and their subdivisions into periods; 
Laurentian, Cambrian, Lower Silurian, Upper Silurian, 
Devonian, Carboniferous, Triassic, Jurassic, Cretaceous, 
Tertiary, Quaternary, and Modern. ‘This arrangement is 
therefore geological, but incidentally it is also biological, 
and follows the same system as that on which the synoptic 
collection of the museum of systematic botany is arranged, 
inasmuch as the plants of the earlier periods are low in the 
scale of life, consisting of thallophytes and pteridophytes 
and plants of uncertain botanical determination, while 
those which appear in the successively later periods are of 
successively higher and more complex types, represented 
y cycads, conifers and both monocotyledonous and dicoty- 
ledonous plants closely related to our living flora. 
