the bread-fruit (similar to our tropical form) grew in Oregon. 
Palms flourished in Colorado. Conifers were extremely abundant 
and of many kinds. Sequoias (redwood, “big trees” of Califor- 
nia) of many varieties during this era were distributed all over 
the world, both south and north, instead of being confined to their 
present small Pacific coast area. Europe, perhaps, in its flora, 
was more like the India of to-day — a mixture of temperate and sub- 
tropical plants. Little is known of the North American flora just 
preceding the glacial period, but in Europe tropical and sub- 
tropical forms gradually disappeared .while temperate forms, such 
as tulip trees, poplars, and oaks, took their place. Plant life just 
before the reign of ice approximated very closely that of to-day, 
though it was differently distributed. Tulip trees, sequoias, and 
magnolias, once plentiful, have long been absent from European 
floras, while the ranges of many of our North American plants 
have been much altered. 
While the earlier part of this era was marked by great volcanic 
activity all over the northern hemisphere, the latter part is re- 
markable for its reign of ice. Several great ice sheets swept over 
parts of the northern and southern hemispheres, and reindeer 
lived as far south as France and Arkansas. Arctic plants came 
south during the glacial period and retreated north again during 
the periods of mild climate, or up the mountain peaks, which 
answered the same purpose; e. g., the Alps and the White Moun- 
tains. Climatic changes resulted in the extinction of much of the 
northern flora; hence, to-day the southern hemisphere, where 
climatic changes perhaps were not so destructive, is a vast 
museum of relics of a flora that was once world wide, while in 
the northern hemisphere, in general, the plants are much more 
modern. Somewhere during this era, possibly in Malaysia or 
southern Asia, man appeared, and, at the time of the ice age, he 
had discovered Europe. 
Since his coming, changes in geography, climatic and plant 
distribution have been and still are in progress, as any serious 
student of these subjects will tell you. New forms of plants are 
still arising, as any plant-breeder or modern-trained student of 
plant evolution will’affirm. These are no longer subjects for argu- 
ment; from the realm of theory they have been transferred to that 
of fact. To-day the oldest living things are the giant sequoias or 
redwoods of California, some of which are over 3,000 years old. 
To-day the plant world is largely dominated by the flowering 
plants, both in number of species and individuals. From this 
standpoint the following list of plant species belonging to each of 
the large groups maybe interesting, though the number of species 
sheds but little light upon the actual numerical predominance of 
individuals of a species in a given flora. These figures are ap- 
proximations: 
Flowering plants 125,000 
Conifers 450 
Ferns 3,500 
*Club-mosses and allies 500 
Mosses and liverworts 12,000 
Fungi and bacteria 64,000 
Lichens.. 5,500 
Algae (seaweeds, pond slimes, etc.) 14,000 
224,950 
♦From the standpoint of the fossil record and those who study it, there is 
no justification, save that of custom, for considerine the club-mosses as fern 
allies. If these students have correctly interpreted the rock-wriften records, 
the ancestors of our present-day ferns and lycopods are much further apart 
than ferns and flowering plants, at least as regards the time element. 
7 
