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bling the Algae. They are included in the Bryophyta mainly 

 on account of their life-history and the structure of their 

 reproductive organs. Those which possess leaves usually have 

 the leaves inserted in two rows. 



Mosses. The mosses are small herbaceous plants, showing a distinct 



differentiation into a slender, often wiry, stem and small 

 green leaves, which are commonly found growing in damp 

 shady places, on the ground, on trees, rocks, etc. 



The leaves are usually arranged spirally and not in two rows 

 as in the Liverworts. They possess no true vascular bundles, 

 and consequently the leaves, which have a very simple 

 structure and are usually only one cell thick, exhibit no distinct 

 venation, although a rudimentary midrib may be present. 

 The roots of these plants do not possess the elaborate structure 

 of true roots, but are very simple organs, consisting of single 

 rows of cells and are known as rhizoids. The characteristic 

 fruit of a moss is a stalked capsule, called the sporogonium, 

 which contains microscopic spores. These, on germination, 

 develop a growth of minute green filaments called the protonema, 

 on which buds arise. From these buds are produced what we 

 know as the moss plant. The microscopic reproductive organs 

 arise in groups at the apex of the shoot, or in the leaf axils. 

 The male organs, termed antheridia, are stalked and club- 

 shaped and contain a number of small cells. When mature the 

 antheridium ruptures at the apex and expels these cells. 

 Each of the latter then liberates a minute twisted filament 

 called the spermatozoid which is provided with two long 

 cilia. The female organs, termed the archegonia, are flask-shaped 

 with a slender neck. The dilated basal portion contains a 

 , naked mass of protoplasm called the egg-cell, or oosphere, which 

 lies in the bottom of the archegonium like jelly in a flask. The 

 spermatozoids, swimming by means of their cilia, in the dew or 

 rain water with which the sponge-like moss tufts are so often 

 saturated, reach the archegonium, pass down its neck and one of 

 them penetrates the oosphere. With the fusion of the proto- 

 plasm of these two bodies fertilisation is accomplished and the 

 fertilised oosphere, which is now called the oospore, surrounds 

 itself with a cell-wall and at once begins to grow and to divide. 

 After the first cell-division has taken place, the body is no longer 

 called the oospore but the embryo. By further growth and 

 division this embryo eventually develops into the sporogonium, 

 bearing the well-known moss-capsule at its apex and with its 

 foot sunk in the tissues of the moss plant. The capsule itself 

 is called the them and it is often provided with a long stalk called 



