34 LIVERWORTS. MARCH ANTIA. 



Mosses, being distinguished by certain peculiarities of fructifi- 

 cation. Others, however, have no distinct stem or separate 

 leaves; but extend horizontally into a flat leaf-like expansion; 

 the fructification is sometimes elevated above this on a little 

 stalk; but in the tribes most nearly allied to the Lichens, it is 

 imbedded in it, as it is in that group. Their general habits 

 closely resemble those of the Mosses. Their leafy expansions 

 are soft and green ; differing much, therefore, from the dry scaly 

 crusts of the Lichens. They are capable of reviving, like the 

 Mosses, after being dried up; and, from the rapidity of their 

 growth, and a peculiarity in their mode of propagation, they are 

 often seen to spread over a damp surface 

 with great rapidity. One of the most 

 common species is the Marchantia poly- 

 morpha, which will be often referred to 

 in this treatise, on account of the many 

 interesting facts which the attentive study 

 of it has disclosed. It is usually found 

 growing on moist surfaces, and often where 

 there is little or no soil ; it is very com- 

 mon in the chinks between paving-stones 

 F.G. 6.-M A R,HANTTA POLY- in unfrequented places, and on the surface 



eof the commonest of the earth contained in garden-pots, as 



of the Liverworts. 6 



also upon walls which from any cause are 

 kept constantly damp. 



33. Besides the regular fructification, this little plant has a 

 very curious apparatus, for the production of small leafy bodies, 

 which may be regarded as buds, and which spontaneously sepa- 

 rate from the parent structure and develop themselves into new 

 beings. As these, when mature, are liable to be washed out of 

 their receptacle by rain, and to be carried to different parts of 

 the neighbouring surface, and as they grow very rapidly whilst 

 supplied with moisture, the rapid extension of the plant under 

 such circumstances is easily accounted for. The little receptacles 

 of a basket-form, in which these are produced, may be generally 

 seen in some stage of their growth, on the upper side of the 

 leafy expansion of which the plant consists ; and they constitute 



