144 



LIVERWORTS AND SCALE MOSSES. 



*" 



known as the sporangium or theca, and its contents are called sporules ; but besides these, 

 there are several bodies called prosphyses, enveloped in a membrane which subsequently 

 bursts, and is curved to form the calyptra. The calyptra is termed dimidiate when the 

 sporangium bursts on its side, and milriform when the membrane is detached at its base. 

 The sporangium is covered by a lid or operculum, and incloses a multitude of sporulea 

 surrounding the central axis, or columnella, and oftentimes inclosed in several cells, 

 with their septa attached to the columnella. The whole rests upon an elevated stalk, or 

 seta. It is lined and also inclosed by two membranes the inner and outer peristomin 

 which have a toothed edge ; and by closing the orifice, especially when moistened, as 

 by the breath, constitute the tympanum. It is bounded above by an elastic external 

 ring, or annuls. 



Whether any, and what part of the above organs can be appropriated to the 

 sexes, is a subject of much dispute ; but it is highly probable that the sporules are 

 the analogues of the pollen in flowering plants, and it has been ascertained that they emit 

 tubes very similar to pollen tubes. 



7 There is an arrangement of the internal parts 



of the organs of fructification in the Horse-tails 



which greatly resembles that described in the 



Lycopodium viz., a spiral 



fibre moving with great 



rapidity, and influenced, as 



in the Funaria, by mois- 



ture. There are usually 



* or ore suet fibres 



having an enlargement at 



their free ends, and connected to a central organ, around which 

 they wrap themselves spirally (Fig. 289). On the application of 

 moisture they instantly wrap themselves around the spore, b, but 

 on it its withdrawal they relax their hold, a. These structures are 

 contained with cases or sporangia, which are arrarged around 

 the apex of the stem in the form of a cone (Fig. 290). It is 

 probable that the elaters represent the male, amd the spores the 

 female parts of the sexual organs. 



In Liverworts, as Marchantia polymorpha, the foliaceous organ 

 is termed thatttis or frond indifferently, and is a flat lobed organ, 

 lying flat upon the ground. Its reproductive organs are three in 

 number . 1st., little green bodies, or buds, placed in cups (Cys- 

 tulae) on the upper surface of the frond, believed to be a vivi- 

 parous apparatus ; 2nd., sporangia, or female parts, placed beneath. 

 calyptra, or a stalked receptacle ; and 3rd., oblong bodies, or 

 anthers, found in other sporangia on the upper surface of the 

 frond. These last resemble the spiral fibres of the Chara vul- 

 gar is (Fig. 291). 



The Scale Mosses (Jungermannia) have a pericladium arising amongst the leaves, 

 from which a seta proceeds, and bears a valvular brown case, or sporangium, containing 

 a number of spiral fibres (Fig. 295), which are highly hygometric, and are intermixed 

 with sporules, or female organs. There is also a calyptra or the ruptured membranous 

 bag (Ej)igonium}. 



290. The Equise- 

 turn, or Horse -tail, 

 with fructification. 



