292 INTRODUCTION 



many of which originated from the Greek. Commonly the names 

 express some prominent characteristic of the group. The names 

 of the divisions end in fhyta, commonly written — p/iyfe, from 

 the Greek word phyton, meaning plant. The names of classes 

 commonly end in —ineae or eae. Thus the Monocotyledoneae 

 is the class consisting of Monocotyledons and Dicotyledoneae the 

 class consisting of Dicotyledons. The names of orders usually 

 end in —ales and usually the name is derived from the name of 

 some prominent family included, as the Rosales from the Rosaceae, 

 the Rose family, one of the important families of the order. 

 Families are commonly designated by terms ending in —aceae, 

 and commonly the terms are derived from some prominent genus 

 of the family, as the Magnoliaceae from the genus Magnolia and 

 Lihaceae from the genus Lily. A species has two names. For 

 example the scientific name of Red Maples is Acer rubrum. 

 Acer is the name of the maple genus and rubrum, the Latin 

 word for red, is the term which designates the species. Juglans 

 nigra is the scientific name for Black Walnuts and Juglans cinerea 

 for White Walnuts or Butternuts. Juglans is the name of the 

 genus while nigra and cinerea are the names of the species. 



The Divisions of the Plant Kingdom. — The phylogenetic 

 divisions of the Plant Kingdom arranged in phylogenetic 

 order are Thallophytes, Bryophytes, Pteridophytes, and Spermato- 

 phytes. 



The Thallophytes are the simplest plants and are regarded as 

 the lowest and most primitive from the standpoint of evolution. 

 The word means thallus plants. As previously stated the 

 ending -phyte always means plant. Thallus refers to the fact 

 that the plant body has a simple organization. It is not differen- 

 tiated into roots, stem, and leaves'. Bacteria, Toadstools, and 

 Algae are familiar Thallophytes. The plant body of some of 

 them consists of a single cell, which is the simplest plant body 

 possible. 



The Bryophytes are so named because they are chiefly Moss 

 plants. Besides the Mosses, they also include the Liverworts. 

 The Bryophytes have better organized plant bodies than the 

 Thallophytes and are, therefore, considered higher in the scale 

 of evolution. 



The Pteridophytes are so named because they include the Fern 

 plants. Most Pteridophytes are Ferns, but this group includes 



