214 ON THE STUDY OF THE MOSSES. 



head ; these antheridia may be readily obtained by carefully dissecting away 

 the leaves of the catkins, which are usually reddish or brown, and often 

 occur near the summit of the stem. If the antheridia of ordinary 

 mosses are examined mici'oscopicallj' with a J or ^-inch objective, 

 they will be seen to contain a number of closely packed cellules, and in 

 each of these cellules a spiral thread-like body may be seen. This 

 spiral body is the antherozoid or fertilising principle of the antheridium 5 

 and, supposing that the antheridium is ripe, a very slight pressure of 

 the cover glass will cause it to burst at the apex, and the enclosed 

 ceUules wiU be seen swarming out with a sort of jerky motion, (7 c.) 

 In a few minutes the cellulose coat of the cellules is dissolved, and the 

 spiral bodies, the antherozoids, thus hberated, commence moving about 

 in the water, much like some infusoria. 



This beautiful sight may be seen readily, and the star-like male 

 flowers of Polytrichum are the most easil}' examined. These should be 

 got about the end of May or in June. The outer leaves of the iiowers 

 should be dissected away, and some of the ripe antheridia shoiild be 

 examined in water with the 4-lOth or J-inch objectives. 



The archegouia, (9,) (which, with the exception of the Sphagnums, 

 are also surrounded by paraphyses,) are somewhat flask-shaped bodies, 

 the upper part consisting of a slender neck, (9 a,) the lower part being 

 somewhat pear-shaped, (9 b.) In the centre of the pear-shaped body, 

 and near the top, is a small cavity, within which a nucleated cell is 

 developed, called the germinal vesicle, (9 c ;) and after the archegonium 

 has acquired some size, a closed canal will be seen passing down tho 

 neck, (9 d,) into that part of the pear-shaped body in which the germinal 

 vesicle, (9 c,) is situated. After a while, as growth goes on, the cells 

 bounding the top of the neck fall away, thus leaving an open passage 

 down the canal to the germ cell. Down this canal the antherozoids 

 pass, and reaching at length the germ cell bring about impregnation. 



After impregnation has taken place ceU-division commences in the 

 germinal vesicle, and continues until by frequent repetition the fruit 

 rudiment is formed. During this time the archegonii;m increases in 

 size, the rudiment growing longitudinally, and striking deep down into 

 the base of the archegonium. This continued upward and downward 

 pressure on the delicate tissues of the archegonium causes it to rupture 

 near the base ; the upper part being carried upwards by the growing fruit 

 rudiment, (10 d,) forms tho hood or calyptra, (10 a,) the lower part is left 

 surrounding tho base of the rudiment and forming a sheath, which is 

 caUcd tlie vaginula, (10 c,) (Lat., a little sheath.) At the top of the fi'uit 

 rudiment the capsule is formed within which the spores are developed. 



By virtue of the insertion of tho fruit-stalk mosses are divided into 

 two sections, Acrocarpi, or those mosses which have tho fruit-stalk 

 terminating tho main stem, (•!,) as in Pottia trnncata, and Pleurocarpi, or 

 those mosses which have tho fruit-stalk arising from the side of the stem, 

 (5,) as in Iljipintvi riitobulum. 



The fruit-stalk, which is always present, varies in length ; in some cases, 

 as in Phascum .lerratum, it is very short, in other cases it may be long 

 and conspicuous; it is usually smooth, but sometimes the surface is 



