14 



character your specimen does not have. Then outside aid must be sought. 

 One who is interested in naming the flora of a region should have one or 

 more manuals of botany that go into more detail than can be given in a 

 flora of this kind. An illustrated manual will be of great assistance. 



After you have reached the family name, turn to the page in the book 

 where the family is found and proceed through the family key to the 

 species. 



Sequence of families and genera. — The sequence of families and genera 

 and their interpretation is that of the "Genera Siphonogamarum" by 

 C. G. de dalla Torre and Dr. H. Harms. This sequence is in accord with 

 the "Engler and Prantl" system of classification which is in current use 

 by most authors. I am aware that several newer systems of classification 

 have been offered but students are not unanimous in accepting them. An 

 exception has been made in the Graminae in which the sequence is that 

 of Hitchcock's Manual of Grasses which is used by most students of grasses. 



It is to be noted that the numbers that precede family and generic names 

 in our manuals and floras differ. This disagreement follows because each 

 author treats a different area and he numbers only the families and genera 

 that are found within the area he considers. The innovation in this flora 

 is that the numbers of families and genera refer to the families and genera 

 of the whole plant kingdom and are the numbers assigned to them by dalla 

 Torre and Harms. This system places no limit upon expansion if one 

 wishes to build up an herbarium and makes it easy to incorporate it into a 

 large herbarium. Plants in an herbarium should not be arranged alpha- 

 betically but according to their relationship. 



Indiana, its location, drainage, and climate. 



Indiana is one of the north-central states. It is about 153 miles wide 

 and 275 miles long between the most distant points. The southern boun- 

 dary is low water line of the north side of the Ohio River and the northern 

 boundary is Lake Michigan and the state of Michigan. The most southern 

 point is in 37° 40' north latitude and the most northern point is in 41° 50' 

 north latitude. In longitude it lies between 84°49' on the east and 88°2' 

 on the west. 



The land area occupies 36,045 square miles besides 280 square miles of 

 rivers and interior lakes and 230 square miles of Lake Michigan. 



The whole of the state has been glaciated except the south-central and 

 southwestern parts (see map on page 1164). The highest point in the state 

 is in Randolph County, 1,285 feet above sea level, and the lowest is at the 

 mouth of the Wabash River, 313 feet. The average elevation is about 

 700 feet. 



About nine-tenths of the state drains westward and south westward into 

 the Mississippi Basin and about a tenth, located in the northern part, 

 drains into the St. Lawrence Basin. 



The average annual precipitation is about 39 inches. The average 

 annual temperature is about 52 degrees Fahrenheit. The average growing 

 season is about 158 days in the northern part of the state and 188 days in 

 the southern part. (See plates on pages 1162 and 1163.) 



