( I2 °) 



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 11 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 

 by cycads, conifers and both monocotyledonous and dicoty- 

 ledonous plants closely related to our living flora. 



