n] 



SUN AND SHADE FORMS OF LEAVES 



39 



the Bracken and the Hart's Tongue. How direct the effect may be is shown 

 by Fig. 46, where (i) represents a section of a pinna of Pteridiuni which had 



Fig. 44. Odontosoria acuhata, a well known "Bramble Fern" from the West Indies. 

 (I size. After Christ.) (See text.) 



been exposed to sun and wind during development, while (ii) shows a section 

 of a pinna of the same leaf which developed in the shade. Such observations 

 give the key to certain features in the general habit of Fern-leaves. 



