C 103 ] 



XII. On the Development of the Spores and Maters of Marchantia polymorpha. 

 By Arthur Henfrey, Esq., F.B.S., F.L.S. fyc. 



Read November 20, 1849. 



M. MIBJBEL*, in the first of his celebrated essays on the structure and development of 

 Marchantia polymorpha, expresses himself in a note in the following terms : — " The 

 origin of the elaters would, I think, be a curious discovery. I should not be astonished 

 if most direct and positive observations led one day to the conclusion that these organs 

 are but one of the numerous modifications which the utricles undergo. Such a result would 

 decide many questions which we have long been endeavouring to solve." 



In his second memoir on the same subject f, he announced the fact that he had 

 observed the development of these bodies from the utricles ; and the progress of vegetable 

 anatomy since that time has made it a matter of certainty, that all the forms of the 

 elementary tissues are to be referred to a cellular type. But so far as I can discover, all 

 observers, who have hitherto investigated the development of the spores and elaters of the 

 Hepaticce, have overlooked certain important points. In the course of a series of observa- 

 tions on the development of spores, made in reference to the theories of cell- development 

 in general, my attention was strongly attracted to a very peculiar condition which I met 

 with in the young sporangia of M. polymorpha, and as I can find no notice of the phe- 

 nomena in the works of previous authors, I am induced to publish an account of them. 



The spores of Marchantia are produced, as is well known, in sporangia enclosed in 

 peculiar receptacles or involucres situated at the base of the rays of the stellate body 

 borne on the pedicel, on the under side. It is unnecessary to notice the characters pre- 

 sented by the envelopes of the sporangia, as these have long since been well described 

 and figured ; the whole course of development of these parts is beautifully illustrated in 

 the memoirs of M. Mirbel already referred to. 



The first indication of the production of the sporangia is the appearance of the organs 

 called pistillidia, exactly resembling those of the other Sepaticce and of the Mosses. 

 Within the enlarged base of the pistillidium a small globule of a green colour is soon met 

 with; this is the nascent sporangium, and in its subsequent development it enlarges 

 within the expanding cavity of the pistillidium, acquiring a pyriform shape, and exhibit- 

 ing at one period a little filamentous process at its apex. The nature or import of this 

 process I cannot make out, but I found it also in Sphcerocarpus terrestris, and it is 



* Recherches anatom. et physiol. sur le Marchantia, &c, Mem. de l'Acad. Roy. des Sc. de l'lnstitut de France, 

 vol. xiii. p. 337. 



t Complem. des Observ. sur le Marchantia, &c. loc. cit. xiii. p. 375. 



p2 



