104 REPORT — 1851. 



published, in opposition to Schleiden's observations, an account of the pro- 

 duction of spiral filaments from the small spores of Pilularia, and finally 

 M. Mettenius* discovered them in the small spores o{ Iso'ctes. Thus they 

 were shown to exist in all the families above enumerated, with tlie exception 

 of the Lycopodiaceae, in which they have recently been stated to exist by 

 M. Hofmeisterf . Before entering into a detailed account of their discoveries, 

 it may be mentioned, that, besides their well-known occurrence in the Cha- 

 racese, which most authors consider as Thallophytes, antheridia are stated by 

 Niigeli to exist on the Florideaj, among the Algae ; and peculiar bodies to 

 which the same nature has been attributed, were recently discovered by M. 

 Itzigsohn in the Lichens; a discovery confirmed by Messrs, Tulasne, who 

 state that analogous bodies exist in many Fungi. Our knowledge of these 

 latter points is, however, far less definite than that concerning the higher 

 tribes, and I shall not include them in the following summary. 



One of the most remarkable circumstances concerning the antheridia of 

 the leaf-bearing Cryptogams, is the very varied nature of the time and place 

 of their development ; so great indeed is this, that it is only their essential 

 structure, and the production of the moving spiral filaments in particular, 

 which warrants the assumption of their identity of function in the different 

 families. In order to make these variations clearly comprehensible, it will 

 be necessary to describe the characters exhibited in the germination of the 

 spores in each tribe, as it is only by this means that the important peculia- 

 rities of each case can be made evident. It will be most convenient to give 

 a separate sketch of all that is known of the process of reproduction in each 

 family, taking these separately and in succession; after this we shall be in a 

 position to compare them together, and trace out their differences and ana- 

 logies ; the advantage of recalling all the essential facts to memory will, I 

 trust, serve as an apology for the introduction of much that is already fami- 

 liar to most botanists. 



Mosses. — 'i'he antheridia of the Mosses occur in the axils of the leaves 

 or collected into a head, enclosed by numerous variously modified leaves, 

 at the summit of the stem. Tliey are produced either on the same heads as 

 the pistillidia, or in distinct heads on the same individuals, such Mossesbeing 

 called monoecious ; or tlie heads are found only on distinct individuals, such 

 Mosses being termed dioecious. 'J"he structure of the anthcridium is ex- 

 ceedingly simple; it consists of an elongate, cylindrical or club-shaped sac, the 

 walls of which are composed of a single layer of cells, united to form a de- 

 licate membrane. Within this sac are developed vast numbers of minute 

 cellules, completely filling it, and, the sac bursting at its apex at a certain 

 period, these vesicles are extruded. When the nearly perfect sacs are 

 placed in water, the vesicles within appear to absorb water, and swell so as 

 to burst the sac of the antheridium, and often adhering together, they col- 

 lectively appear to form masses larger thnn the cavity from which they have 

 emerged. Through the transparent walls may be seen a delicate filament 

 with a thickened extremity, coiled up in the interior of each vesicle. Often 

 before the extrusion, but always shortly after, a movement of this filament 

 is to be observed when the object is viewed in water under the microscope. 

 The filament is seen to be wheeling round and round rapidly within the 

 cellule, the motion being rendered very evident by the distinctness of the 

 thickened extremity of the filament, which appears to be coursing round the 

 walls of the cellule in a circle. According to Unger, this filament breaks 



* Beitrage im Botanik, Heft 1. Heidelberg, 1850. t Flora, 1850, p. 700. 



