ANTHERIDIA. 361 



side by side now end the series. These now go on 

 developing other cells, by division both transverse and 

 longitudinal ; the result of which is, that the tip of 

 the confervoid rapidly assumes a flat, fan-like shape, 

 and is recognisable as the protliallium ; a condition 

 in which the new growth very closely resembles the 

 common Liverwort (Marckantia) , which spreads its 

 expansions so commonly over the earth in damp 

 situations. 



We shah 1 be greatly mistaken, however, if we sup- 

 pose these green laminae which lie so thickly over- 

 lapping each other, and sparkle so prettily, in our 

 seed-pan, to be the future Ferns. The protliallium 

 does not enter into the composition of the future plant 

 at all ; it is but a sort of foster-mother by which it is 

 reared. In it, however, occur a series of develop- 

 ments of most remarkable character. When the 

 prothallium has attained dimensions which make it 

 distinctly visible to the naked eye, minute warts begin 

 to form on its under surface, which are called the 

 antJieridia, from their performing functions analogous 

 to the male organs (anthers) of higher plants. Each 

 antlieridium is composed of a large central cell, sup- 

 ported by one cylindrical or two semi-cylindrical cells, 

 covered by a cell having the form of a segment of a 

 sphere, and surrounded by a ring of several smaller 

 cells. By and by the central cell, having increased 

 in size, is transformed by internal divisions into a 

 globe containing several cubical cells ; and in each of 

 these latter there is now produced what has the form, 



