Bagnall : Sexual Reproduction of Ferns and Mosses. 89 



confervoid thread-like growth, called the pro-embryo, or protonema. 

 In some mosses, however, such as the Sphagna, or bog mosses, the 

 spores, on germinating, give rise to a flattened MarchantiaASkoi 

 structure, somewhat similar in appearance to the prothallus of a fern, 

 agreeing, however, in similarity only. The protonema is formed by 

 the protrusion of the inner coat of the spore. This, by rapid cell 

 division, becomes much elongated and branched. The primary 

 branch, at first green, frequently turns brown, and in some cases 

 penetrates the ground, thus performing the functions of a root. The 

 secondary branches, however, are well charged with chlorophyll, and 

 branch and branch again repeatedly. The protonema of mosses may 

 constantly be seen forming a green, velvety mass where mosses are 

 found fruiting, more especially after wet warm weather, and looks 

 very like the smaller conferva. If a little of this mass be examined 

 with a moderate magnifying power, it will be seen that at or near the 

 base of some of the secondary branches a sm'all bud-like body is 

 developed. This is the first bud of the moss plant, and this bud-like 

 body grows by continually repeated divisions of the apical cell, until 

 at length the first rudimentary leaf is given off ; growth still con- 

 tinues, and ultimately the leafy moss is developed. 



The various stages of development may often be traced by carefully 

 examining a small mass of protonema. In most mosses this proto- 

 nema is short-lived, and perishes before the moss is fully grown ; but 

 in some of the lower forms, such as PJiascim serratum^.it is permanent, 

 lasting throughout the life-time of the plant. The examination of 

 such mosses is both instructive and interesting, as we may often see 

 at one glance the whole life history of the plant—the germinating 

 spore, the protonema, the fruit and its spores. 



We saw that in the case of the ferns the organs of reproduction 

 were developed on the Marchantia-like structure, formed from the 

 inner coat of the germinating spore ; but in the mosses these organs 

 are not developed until the leafy moss plant is fully grown, and occur 

 as bud-like bodies in the axils of certain of the leaves, either at the 

 top, the side, or the base of the stem, according to the class or 

 species examined. 



These may be seen with an ordinary field lens, and if carefully 

 dissected will be found to consist of a number of leaves enveloping 

 the organs of reproduction — the antlieridia and arcliegonia. The leaves 

 surrounding the antheridea are called the perigonial leaves, whilst 

 those surrounding the archegonia are called the perichsetial leaves ; 

 and I may also state here that the male bud is usually smaller than 



