78 



BEGINNERS' BOTANY 



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from leaves. As a rule leaves can be distinguished by 

 the following tests: (i) L,&a.ves are temporary s/ructu/rs, 

 sooner or later falling. (2) Usually iicds are borne in their 

 axils. (3) Leaves are usually borne at joints or 

 7wdes. (4) They arise on wood of the current 

 years growth. (5) They have a more or less 

 definite arrangement. When leaves fall, the twig 

 that bore them remains ; when leaflets fall, the 

 main petiole or stalk that bore them also falls. 



Shapes. — Leaves and leaflets are infinitely 

 variable in shape. Names have been given to 

 some of the more definite or regular shapes. 

 These names are a part of the language of bot- 

 any. The names represent ideal or 

 typical shapes ; there are no two 

 leaves alike and very 

 few that perfectly con- 

 form to the definitions. ^ 

 The shapes are likened 

 to those of familiar ob- 

 jects or of geometrical 

 Fig. 102.— figures. Some of the 

 Linear- commoner shapes are as 



ACUMINATE ^ ,, , ... 



LEAF OF follows (name origmal fig. ios.-Short-obi.ong 

 Grass. examples in each class): Leaves of Box. 



Linear, several times longer than broad, with the sides 



\ nearly or quite parallel. Spruces and most grasses 

 are examples (Fig. 102). In linear leaves, the main 

 veins are usually parallel to the midrib. 

 Oblong, twice or thrice as long as broad, with the sides 



\ parallel for most of their length. Fig. 103 shows the 

 short-oblong leaves of the box, a plant that is used 

 for permanent edgings in gardens. 



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