EXCURSION ON THE RIO NEGRO. 337 



has its leaves arranged according to the fraction of -f^ ; but, 

 though the crown consists of several cycles of leaves, they 

 do not form a close head, because the older ones become 

 pendent, while the younger are more erect. The Pupunha, 

 or peach palm (Guilielma), follows the Phyllotaxis of ^ 8 T ; 

 but in this instance all the leaves are evenly arched over, 

 so that the whole forms a deep-green vault, the more beau- 

 tiful from the rich color of the foliage. When the heavy 

 cluster of ripe, red fruit hangs under this dark vault, the 

 tree is in its greatest beauty. As the leaves of this palm 

 are not so closely set in the younger specimens as in the 

 older ones, its aspect changes at different stages of growth ; 

 the leaves in the younger trees being distributed over a 

 greater length of the trunk, while, in the adult taller ones, 

 they are more compact. This arrangement is repeated in 

 the Javari and Tucuma (Astrocaryum) ; but in these the 

 closely-set leaves stand erect, broom-like, at the head of the 

 long stalk. In the Mucaja (Acrocomia) the leaves are ar- 

 ranged according to the fraction -J|. Thus, under the 

 same fundamental principle of growth, an infinite variety is 

 introduced, among trees of one order, by the slight dif- 

 ferences in the distribution and constitution of the leaves 

 themselves. In the Musacea3, or Scytamineae, the Bananas, 

 another order of the same class of plants, a diversity equally 

 remarkable is produced in the same way, namely, by slight 

 modifications of this fundamental law. What can differ 

 more in appearance than the common Banana (Musa par- 

 adisiaca), with its large simple leaves, so loosely arranged 

 around the stem, so graceful and easy in their movements. 

 and the Banana of Madagascar (Raven ala madagascariensis), 

 commonly known as the Traveller's tree, which, like the 

 Baccdba of Para, has its leaves alternating regularly on op- 



15 v 



