338 HOW CROPS GROW. 



as regards the structure of their fruit. They are accord- 

 ingly grouped together into a natural family or order, 

 which differs from all others. 



Classes, Series, and Classification — Classes are 

 groups of orders, and Series are groups of classes. In 

 botanical classification, as now universally employed — 

 classification after the Natural System — all plants are 

 separated into two series, as follows : 



1. Flowering Plants [Phanerogams), which produce 

 flowers and seeds with embryos, and 



2. Flowerless Plants [Cryptogams), that have no 

 proper flowers nor seeds, and are reproduced, in part, 

 by spores which are in most cases single cells. This 

 series includes Ferns, Horse-tails, Mosses, Liverworts, 

 Lichens, Sea-weeds, Mushrooms, and Molds. 



It was belieyed, until recently, that there exists a sharp and abso- 

 lute distinction laetween flowering and flowerless plants, but our 

 larger knowledge now recognizes that here, as among genera, species, 

 and varieties, kinds merge or shade into each other. 



The use of Classification is to give precision to our 

 notions and distinctions, and to facilitate the using and 

 acquisition of knowledge. Series, classes, orders, genera, 

 species, and varieties are as valuable to the naturalist as 

 pigeon-holes are to the accountant, or shelves and draw- 

 ers to the merchant. 



Botanical Nomenclature. — The Latin or Greek 

 names which botanists employ are essential for the dis- 

 crimination of plants, being equally received in all coun- 

 tries, and belonging to all languages where science has a 

 home. They are made necessary, not only by the confu- 

 sion of tongues, but by confusions in each vernacular. 



Botanical usage requires for each plant two names, 

 one to specify the genus, another to indicate the species. 

 Thus all oaks are designated by the Latin word Quercus, 

 while the red oak is Quercus rubra, the white oak is 

 Quercus alba, the live oak is Quercus virens, etc. 



