to 21; with line 21b, referring to 22; with 22b, referring to 29; with 

 29b, referring to 32; with 32c, referring to 47; with 47b, referring to 

 48; with 48b, referring to 51; with 51b, referring to number Ib in the 

 Beech Family. Turning to the proper number in this family, the plant 

 is referred to line 3; it agrees with line 3c, referring to 10; with lOa, 

 referring to 11; and with lib, which gives the name of the plant, White 

 Oak, Quercns alba. 



As a second example, suppose one has a common yellow-flowered 

 plant blooming on lawns and roadsides in spring. Under the Key to 

 the Groups, it agrees with Ib. referring to 2; with 2b, referring to 3; 

 and its net-veined leaves place it in 3b, referring to Group 4, Dicotyle- 

 dones. Under this group, its basal leaves place it in Ib, referring to 

 2; its simple leaves in 2b, referring to 18; the absence of stem-leaves 

 places it in 18b, referring to 23; its solitary flowers on each flower- 

 stalk place it in 23b, referring to 24; its yellow flowers agree with 

 24a, referring to 25 ; and its milky juice refers the plant to number 16, 

 in the Composite Family. In the key to this family, its lobed leaves 

 agree with 16b, referring on to 17; its large flowers with 17b, giving 

 one the common name Dandelion, and referring on to 18 to determine 

 which kind of Dandelion the plant may be. 



At some point in the key there will be found for each plant a 

 statement in parentheses. This is general information concerning the 

 height of the plant, the color of the flowers, or the season of bloom. 

 It must be remembered that the height of plants is subject to great 

 variation; that most plants have white-flowered varieties; and that 

 the month of bloom depends largely on the latitude and the climate. 

 Therefore this general information should not be used as means of 

 distinguishing species. 



The names of plants. Each plant bears a scientific name. This 

 is composed of two parts and is usually of Latin or Greek derivation. 

 In some cases these names are taken directly from the Latin language, 

 as Quercus, the Oak, or Acer, the Maple. In other cases the name may 

 indicate some characteristic feature of the plant, as Polygonum, many 

 joints, for the Knotweed, or Ammophila, sand-loving, for the Beach 

 Grass. 



An English name is also given for almost every kind of plant. In 

 a few cases there is no accepted English name, and none has been 

 given. In many cases the same English name applies to several kinds 

 of plants and has been repeated for each. When this is so, the common 

 name is given in the key in parentheses before the scientific name is 

 reached. Thus, if one is satisfied to know merely that his plant is a 

 dandelion, he learns it in line 17b of the key to the Composite Family, 

 but to discover which kind of a dandelion he has, he must follow 

 through the key and use the scientific name. 



There is in this book, therefore, no necessity of learning or using 

 scientific names. The less critical may be satisfied with an English 

 name, and others may use the scientific names as they see fit. 



