SEA WEEDS 347 



In the Angiosperms the ovules are always enclosed in an ovary, 

 and the pollen grains, alighting on the stigma, are held by a gummy 

 secretion. The tubes they produce then penetrate through the 

 underlying tissues, and thus come into contact with the ovules. 



The Gymnosperms include a group of small palm-like trees and 

 shrubs (the Cycadece), of which the so-called Sago Palm is a repre- 

 sentative ; and the Coniferce or cone-bearing shrubs and trees, which 

 may be spoken of collectively as the Pines. In the latter the leaves 

 are either stiff, linear, and needle-like, or short and scale-like, or are 

 divided into narrow lobes ; and the plants are noted for their resinous 

 secretions. The flowers are always unisexual, and are generally 

 arranged in cylindrical or short catkins, where they are protected 

 by closely packed scales ; but the female flowers may be solitary. 

 There is no calyx or corolla, but the naked ovules and seeds are some- 

 times more or less enclosed in the scales (bracts) or in a fleshy disc. 



The Angiosperms form the highest division of the flowering 

 plants ; and are subdivided into two extensive groups the Mono- 

 cotyledons and the Dicotyledons. The chief distinguishing feature 

 of these is that implied in the above names, the embryo of the 

 former containing but one rudimentary leaf (cotyledon), while that 

 of the latter contains two. The Monocotyledons are also charac- 

 terised by having the bundles of vessels (vascular bundles) of the 

 stems dispersed ; the veins of the leaves are also usually parallel, 

 and the parts of the flower are arranged in whorls of three or six. 

 In the Dicotyledons the vascular bundles of the stem are united 

 into a ring which surrounds a central pith ; the veins of the leaves 

 form a network, and the parts of the flower are arranged in whorls 

 of four or five. 



We are now enabled to understand the relative positions of the 

 principal groups of plants in the scale of vegetable life, and to locate 

 approximately the forms with which we have to deal ; and to aid 

 the reader in this portion of his work we present a brief summary 

 of the classification of plants in the form of a table for reference : 



THE CLASSIFICATION OF PLANTS 



I. CRYPTOGAMIA Flowerless plants. 



(a) THALLOPHYTES Leafless, cellular plants. 



1. Protophyta Unicellular plants. 



2. Algae Sea weeds, <fec. 



3. Fungi Mushrooms, <fec. 



