TEXTURE OF THE LEAF. 136 



trees of Equinoctial regions are perpetually verdant, 

 and the same leaves which have been noticed as unusu- 

 ally large, are equally remarkable on account of their 

 longevity, as they rarely fade till they are six years 

 old ; yet these very trees, when removed to a colder 

 region, are in some cases annually stripped of their 

 foliage. In its native country, the far famed Cydon, 

 and also when cultivated in the South of Europe the 

 Quince tree is evergreen, though here, as we have had 

 an abundant opportunity to see, it annually parts with 

 its leaves. On the other hand the Currant, which was 

 originally an inhabitant of the northern countries of 

 Burbpe, when transferred to the Island of St. Helena 

 was soon crowned with perennial leaves, but it there 

 produces less fruit than in its native country. 



11. TEXTURE OF THE LEAF. 



in examining the texture of the leaf, we shall find 

 the vessels of its petiole diverging in various directions, 

 imbedded in cellular substance, and enclosed by an ex- 

 terior membrane or Epidermis. The latter is trans- 

 parent and delicate, but at the same time sufficiently 

 firm to answer the object for which it was designed, to 

 secure from injury the vessels of the leaf, and to ex- 

 pose its fluids to the necessary agency of air and light. 

 It is sometimes covered with wool or hair, which seems 

 to afford an additional security against the vicissitudes 

 of climate. Plants thus protected are capable of endu- 

 ring a greater degree of heat than any others, and they 

 abound chiefly in the hottest sections of Europe and 

 America. More frequently, however, the epidermis 

 <\f\ f ■:■;■ \« rrv« red w : th v +r .nsparent varnish, which 

 f&ds ic tnur brilliantey, and secures them from the 



