Teacher's Leaflet. 1217 



(8). Note whether the leaves are injured by insect enemies such as 

 aphides or plant-lice, leaf-miners or galls. 



Facts for Teachers. — The Linden's leaves grow alternately on the twigs and 

 unfold very late in the spring. But they make up for that in very rapid growth. 

 One week the tree stands among blooming elms and maples with its branches 

 naked and the swollen little dark-red buds very conspicuous on its numerous 

 twigs; the next, it is clothed all over with tender green leaves which stretch them- 

 selves like magic. Each leaf is heartshaped and about three fourths as wide as 

 it is long. Its edges are saw-toothed. Its sides are unequal,, particularly at the 

 base. Its stem is short, much paler in color than the leaf, strong, round and 

 swollen at both ends where it is attached to the twig and to its own blade. The 

 thickened part of the stem is sweet and full of mucilage, especially when the 

 leaf is growing. 



The tree's roots strike so deeply and spread so widely that it withstands drouth 

 well, and during the great famine in Russia the starving peasants not only saved 

 their cattle by feeding them on its leaves, but ground its thick, mucilaginous 

 inner bark and made nourishing porr dge for themselves. The veins of the leaves 

 are very pale green, very prominent on the under side and their main branches 

 all point toward the base of the leaf. All along the veins at the angles of the 

 branches are little tufts of yellowish brown hairs. 



The Linden holds its broad leaves almost horizontally and they are so numerous 

 that they overlap like the shingles of a roof. A tree that has had opportunity 

 to develop a wide-spreading crown gives a deep and most delightful shade, par- 

 ticularly in the hot days of early summer when it is loaded with fragrant flowers. 

 But alack! the tree is as hasty to doff its leaves in autumn as it was tardy in the 

 spring to don them. Their dull yellow is not so pleasing, either, as the brighter 

 co'ors of the maples. Like the maple, its leaves are infested with gall-mites and 

 leaf miners, which, though they disfigure its beauty, are most interesting to study. 

 Aphides also feed upon and blacken its leaves with sticky blotches of honey-dew, 

 but it has no insect enemy so destructive to its life and beauty as the elm leaf- 

 beetle is to that tree. 



Lesson XL 



THE FLOWER AND THE FRUIT 



Obseroaiions by Pupils: 



(i). When does the Linden bloom? 



(2). Where does it bear its flowers? Do they grow singly or in a 

 cluster? 



(3). Draw, as well as you can, a stem of the flowers and the curious 

 bract to which they are attached. What part of the length of the flower- 

 stem is fast to the bract? Is the bract largest at base or tip? 



(4). What color are the flowers? Are they fragrant? Do they seem 

 to yield much nectar and what insects have you observed visiting them ? 

 Where is the nectary? 



