CHAPTER XXV. 



THE REPRODUCTION OF MOSSES AND LIVERWORTS 

 (BRYOPHYTA). 



PRINCIPAL MATERIALS USED. 



Marcliantia polymorpha (Liverwort), with gemmae ; preferably fresh. 



The same, with male and female receptacles. Preferably fresh. May be 



kept in alcohol. 

 Male " flowers " of a Moss, e.g., Mnium liornum, or Polytrichum. Fresh, 



dried, or in alcohol. (Mnium liornum is very common in woods and 



on shady banks.) 



Female " flowers" of the same. Fresh, dried, or in alcohol. 

 (Both of these gathered in April, May or June.) 

 Spore-capsules of the same. Fresh or in alcohol. 



PRINCIPAL REAGENTS USED. 



Osrnic acid, 1 per cent. Iodine. 



Vegetative Reproduction of Marcliantia. The universally dis- 

 tributed Liverwort, Marchantia polymorpha, the structure of 

 which we studied in chap, xviii., rapidly multiplies vegetatively 

 by its gemmae. These are common amongst liverworts in 

 general, and are here met with in especially beautiful form. The 

 gemmae of Marcliantia, arise upon the dorsal (upper) surface of the 

 thallus in cup-shaped receptacles or cupules (see Fig. 122, B). 

 The cups have a beautifully-toothed rim, and at their bottom the 

 bright green gemmae are visible. 



A median longitudinal section through the cupule, parallel to 

 the long axis of the shoot which bears it, shows that the cup is 

 at first slightly narrowed upwards, and then somewhat suddenly 

 expands into the broad rim. The tissue which forms the air- 

 chambers passes into the exterior of the cup, to above the point 

 where its outward broadening begins. The bottom of the cup is 

 occupied by unicellular club-shaped papillae, the membrane of 



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