﻿On Pa ? m Trees. 



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of the trunk, enclosed in a spathe or sheath. The staminate flowers are 

 nearer the top, and the pistillate nearer the bottom of the same spadix, and 

 l^oth are sessile. The staminate flowers have a three-leaved calyx, a three- 

 petaled corolla, and six stamens. The pistillate flowers have three sepals 

 and three petals, with three sessile stigmas. The flowers are of a pale 

 yellow color. 



The drupes are fibrous ; there are from 12 to 20 in a bunch. They are at 

 first green, then orange, then brown, when mature. The nut is familiar to 

 all. It has three round scars at the base, out of one of which the embryo 

 plant shoots forth. 



The vernation of the cocoanut tree can be best described as consisting 

 of a great number of cones formsd around a common axis and fitted com- 

 pactly one on. top of the other, beginning with one of extreme minute- 

 ness, which is situated exactly at the apex of the trunk of the tree. 



The phyllotaxy of the palm plants is typified in a fossil belonging to the 

 carboniferous age, called Archimedes, and in living mollusks by the 

 Turritella and Scalaria. If you conceive of a vertical axis, with an in- 

 clined line touching it, and gradually ascending with a uniform motion, the 

 free end revolving in space about the vertical axis, the line thus moving 

 will generate a helicoidal surface, and the point, or moving end of the 

 line, will generate a helix. Upon such a helix the leaves on the trunk of a 

 palm tree are arranged. 



This spiral formation exercises a dominant control in the formation of 

 fish, birds and animals. 



In many monocotyledons, as in the maize, in all grasses, in spider-wort, 

 bell-wort and iris, the numerical symbol is the fraction -J, in which the 

 numerator expresses the number of turns around the stem for completing 

 one cycle, or set of leaves, while the denominator expresses the number 

 of leaves in the cycle. 



The general form of the palm carries us back to the fern trees of the 

 carboniferous age, which Caruthers suggests as foreshadowing the mono- 

 cotyledons, and also the dicotyledons, " and that they are probably the 

 progenitors, not only of the tree ferns of the present day, but also of the 

 palms and the foliferous exogens." 



Le Conte's drawing of an ideal section of the Lepidodendron, displays 

 distinctly the manner of growth of the vascular bundles from the central 

 axis of the tree toward the base of the leaf petioles on the periphery. 

 (See Figure 1.) 



