OF THE OUGANS 



77 



theca for it. We distinguish also the operculum, which, when 

 the fruit is fully ripe, loosens itself all round. This loosen- 

 ing is often assisted by a fringed ring {annulus ftmhriatus), 

 which is placed horizontally between the operculum and cap- 

 sule, and by its elasticity throws off the operculum. 



The mouth of the Moss capsules {os, stoma) is ihe upper, 

 circular part, which is either naked {nudum), or is furnished 

 with teeth, cirrhi, and membranes, which arise from the pro- 

 longation of the capsular partitions, and are called perisfomi- 

 urn-, (Tab. II. Fig. 7 8.) Sometimes also a membrane, 

 which in Polytrichum and some others is called epiphragma^ 

 passes across the mouth of the capsule, 



118. 



In Lichens, the whole thallus is capable of producing gra- 

 nular germs, destined for propagation. Yet there are apotlie- 

 cia, which contain apparent, frequently twin-seeds, in peculiar 

 layers; (Tab. II. Fig. 2.) Formerly the various forms of 

 these apothecia were furnished with peculiar names, which, 

 however, are no longer in use. Lirella is a linear longitudi- 

 nally opening apothecium, as in Opegrapha. 



Tric(B are closed, twisted seed-beds, of a black colour. 



Thalamia are close round seed-beds, in the substance of 

 the leaf, surrounded by a peculiar membrane, within which 

 the seeds are enclosed in peculiar bags. 



Tuhercula are close, roundish or spherical seed-beds, which 

 project from the leaf. 



Cephalodia are highly coloured, roundish, open, and com^ 

 monly stalked apothecia, covered with a seed-bed, which 

 passes off like a powder. 



Orbilla are jflat, slightly coloured, open fruits, without a 

 raised margin, covered with a thin seed-bed. 



ScutelliE are open, circular, hollowed fruits, the m.argin of 

 which is formed by the substance of the leaf. 



Patellcc are open, flat or elevated fruits, without a raised 

 margin, 



