SKETCHES 
OF THE 
DEVELOPMENT AND DISTRIBUTION OF VEGETATION, 

READ BEFORE THE SCIENTIFIC ASSOCIATION JANUARY 28, 1887, 
BY T. J. BURRILL, PH. D.. A. A. A.S., ETC., 
Professor of Botany University of Lilinois. 

Ir is universally admitted that the Earth as such had a beginning, and 
that, from that beginning, gradual progress has at length made it what we 
now know it to be. School children study in the geographies the distribution 
of the land and the water into great continents and oceans. They learn of 
islands, of peninsulas, of mountains, of plains, of barren deserts and fertile 
valleys, and of seas, of lakes, of rivers and of springs. They have pictured 
for them the plants and the animals of the polar, the temperate and the 
tropical zones —the wonderful diversity and abundance of the vegetable and 
animal kingdoms. Man himself is presented to them in a variety of races, 
differing from each other in the size and proportions of the body, the com- 
plexion of the skin, the nature of the hair, the peculiarities of the skull and 
the qualities and relative activities of the mental and moral natures. Under 
proper instruction the study is an exceedingly interesting one, to a child, and 
the interest never abates as in maturer years we try to gain wider and deeper 
knowledge of the wonderful facts and marvellous forces of the mysterious 
origin and development of the inorganic and organic world. 
It is the purpose of the present paper to present, with no ostentation of 
learning, a few sketches in the history of the vegetable world. To give a 
suitable basis to our story some preliminary topics must be briefly treated. 
THE GENERAL STABILITY OF THE GREAT GEOGRAPHICAL FEATURES 
OF THE EARTH. 
We take it as acceptably proved that the great physical features of our 
earth,— the general size'and shape of the continents and seas, the great eleva- 
tions of land and the vast areas and prodigious depths of the ocean reservoirs 
— have been permanent characteristics of our earth. 
There have been many local and temporary fluctuations between the level 
of sea and parts of the land, but the fabulous continents of Lemuria and of 
Atlantis are relegated to the brain of their discoverers, and the oceans from 
which in imagination, lost continents reared their dripping heads in the misty 
ages of the past have no place in the latest scientific deductions concerning 
the geological history of the world. Shallow seas of great extent have in- 
deed occupied areas which are now dry land and what was once dry land is 
now covered with some fathoms of water; but the great trough of the Atlan- 
tic ocean, with its almost soundless bottom, has had an existence from the 
