WItHERED LEAVES. 2ll 



annular rings discovered in a transverse section of its trunk. 

 Further, we gather that the flowers possess a symmetrical arrange- 

 ment of four or five parts, or their multiples. For instance, the 

 flower of the apple-tree has a five-toothed calyx, five petals, 

 numerous stamens, styles one to five, and ovaries one to five, deve- 

 loping into one to five seeds in the fleshy pome, which is generally 

 spoken of as the fruit of the apple. On the other hand, the 

 embryo of the monocotyledon has but one seed-lobe or coty- 

 ledon (or, if two, then the accessory one is imperfect and alter- 

 nate with the other, not opposite as in the other class) ; the trunk 

 is composed of cellular tissue, among which the vascular tissue is 

 mixed in close bundles, without any distinction of pith, wood, and 

 bark ; the leaves are parallel veined ; and the several parts of the 

 flowers are arranged in threes or their multiples. A familiar in- 

 stance of an endogenous stem may be seen in a piece of common 

 cane, cut across in transverse section. 



Plate 39, Figure i, shows the single cotyledon in a germinating 

 grain of Indian Corn. Figure 2 is a diagram of the arrangement 

 of floral parts in a monocotyledonous plant, in which the three 

 sepals of the calyx, and the three petals of the corolla alternate 

 with each other. In this example there are six stamens (a multiple 

 of three), disposed in two whorls of three each, also alternating 

 with each other, and with the three pistils. 



Figure 3 exhibits the mode of germination of a bean (Dicoty- 

 ledon), with its two cotyledons opposite to each other, and above 

 these, two of the true leaves, and the growing bud at the apex of 

 the stem. Figure 4 is a diagrammatic representation of the 

 flower of a Dicotyledon, in which all the parts are in fives, or 

 quinary arrangement. 



Perhaps among the withered leaves at our feet may be found a 

 piece of the stem which has been broken off by some strong gust 

 of wind. Let us take it up and examine it. We shall find from 

 the scars of the severed petioles, that the leaves were inserted in 

 what at first sight may appear an irregular and accidental manner, 

 but further observation will reveal a beautiful law and order in 

 their arrangement, and this is technically known as the phyllotaxis 

 of plants, which simply means the relative positions of leaves on 

 the axis. If the broken piece of branch in our hand is from the 



