MUSCINEM. 20^ 



The sexual organs are Antheridia and Archegonia. The mature Anther idiwn is 

 a body with a longer or shorter stalk, of a spherical, ellipsoidal, or club-shaped form, 

 the outer layer of its cells forming a sac-like wall, while each of the small and very 

 numerous crowded cells enclosed within it developes an antherozoid. The anther- 

 ozoids are freed by the rupture of the wall of the antheridium at the apex ; they 

 are spirally coiled threads thicker at the posterior and tapering to a fine point at 

 the anterior end, at which are placed two long fine cilia, the vibrations of which 

 cause their motion. The female organs, which since the time of Bischofif have been 

 called Archegonia, are, when in a condition capable of being fertilised, flask-shaped 

 bodies bulging from a narrow base and prolonged into a long neck. The w^all 

 of the ventral portion encloses the central cell, the protoplasm of which, contracting 

 and rounding off, forms the oosphere. Above this begins a row of cells which 

 passes through the neck in an axial direction, and is continued as far as the cells 

 which form the so-called ' Stigma.' The cells of this a,xial row become broken up 

 before fertilisation, and transformed into mucilage which finally swells up and forces 

 apart the four stigmatic cells. In this manner an open canal is formed, which 

 leads down as far as the oosphere, and enables the antherozoids to enter it. This 

 mucilaginous axial row of cells occurs also in the archegonium of Ferns, but in 

 Rhizocarpese and Lycopodiacex is reduced to a single rudimentary cell. 



The great diversity in the origin of the sexual organs of Muscinese is of 

 extreme importance. In the thalloid Hepaticae these organs arise below the 

 growing apex from the superficial cells of the thallus or of the prostrate thalloid 

 stem, or on specially metamorphosed branches (as in the Marchantieae) ; in the 

 foliose Jungermannie^e and in the Mosses not only the antheridia but also the 

 archegonia may be formed from the apical cell of the shoot or from segments 

 of it ; in this case they may take the place of leaves, or of lateral shoots, or 

 even of hairs. Thus the antheridia appear as metamorphosed trichomes in the 

 axils of the leaves of Radula, as metamorphosed shoots in Sphagnum, as apical 

 structures and also as metamorphosed leaves in Fontinalis. In the same manner 

 the first archegonium of the fertile shoots of Andraea and Radula arises from the 

 apical cell, the later ones from its last segments ; and this is probably the case in 

 Sphagnum. 



Antheridia and archegonia are usually produced in great numbers in close 

 proximity ; in the thalloid forms of the Hepaticse they are generally enveloped 

 by later outgrowths of the thallus ; in the foliose Jungermanniese and in Mosses 

 several archegonia are commonly surrounded by one envelope formed of leaves 

 which is termed the PerichcEtium ; in Mosses a male flower (sometimes a her- 

 maphrodite one) is usually formed in this manner, while the antheridia of the 

 Jungermanniese and of Sphagnum stand alone. Very commonly, especially in the 

 foliose kinds, Paraphyses, i. e. articulated threads or narrow leaf-like plates of cells, 

 are formed in the male and female flowers by the side of the sexual organs. 

 Besides the envelopes just named, there is also often in Hepaticse (but not in 

 Mosses) a so-called Perianth, which grows as an annular w^all at the base of the 

 archegonium, and finally surrounds it as an open sac. 



The Asexual Generation or Sporogonitwi, arises in the archegonium from the 

 fertilised oosphere or oospore. It first developes by repeated cell-divisions into an 



