28 A MANUAL OF FARM GRASSES 



one species. Timothy is also known as Herd's grass and 

 the name Herd's grass is also applied to redtop. In order 

 to standardize names, that they may be understood by 

 botanists in all countries, Latin names have been applied 

 to plants. Botanists have classified plants into families, 

 the families into genera, the genera into species. The 

 grasses form a distinct family among plants. For con- 

 venience, the grasses have been divided into smaller 

 groups. There are about 20,000 species or kinds of 

 grasses. These have been grouped in about 400 genera. 

 Each genus includes the species that resemble each 

 other, the classification being based on the structure of 

 the flowers. A Latin name has been given to each genus. 

 To the bluegrasses, including Kentucky bluegrass, 

 Canada bluegrass, Texas bluegrass, and many wild 

 species all over the world, has been given the name Poa; 

 to the bent grasses, including redtop, Rhode Island bent, 

 carpet bent, and a large number of wild grasses that 

 closely resemble these, has been given the name Agrostis. 

 The species or particular kind in each genus has received 

 a Latin name. Botanically, each kind of grass is known 

 by the Latin name of the genus and species to which it 

 belongs. Bluegrass is called Poa pratensis; Canada 

 bluegrass, Poa compressa; Texas bluegrass, Poa arach- 

 nifera, and so on. The first part of the Latin designation 

 is called the generic name; the second part, the specific 

 name. In this book is given the Latin or botanical 

 name of each grass described. This is done in order 

 that botanists in this country and in other countries may 

 know with certainty the kind of grass described or 

 mentioned. 



