CHAP. III. LICHENS. 229 



not dividing into leaves and stems, but lying horizontally upon 

 the ground, and emitting roots from its under surface. The 

 organs of reproduction consist, firstly^ of a stalked fungus-like 

 receptacle, carrying on its apex a calyptra, and bearing tlieccR 

 on its under side ; secondly^ of a stalked receptacle, plane on 

 the upper surface, with oblong bodies imbedded vertically in 

 the disk, and called anthers ; thirdly, " of little open cups 

 {cystulce), sessile on the upper surface of the fronds, and con- 

 taining minute green bodies {germnce), which have the power 

 of producing new plants." The first kind is usually con- 

 sidered a female flower, its sporules intermixed with elaters : 

 the second male, and the third viviparous apparatus. In 

 the opinion of many modern botanists, the granules of both 

 the two first are sporules : about the function of the last there 

 is no difference of opinion. Mirbel considers the first to be 

 male and female ; but it must be confessed that in structure 

 there is but little analogy between them and the organs of 

 more perfect plants. 



In Anthoceros, while the vegetation is the same as in Mar- 

 chantia, the organs of reproduction are very different. They 

 consist of a subulate column, issuing from a perichaetium 

 perpendicular to the frond, and opening halfway into two 

 valves, which discover, upon opening, a subulate columella, 

 to which sporules are attached without any elaters. There 

 are also cystulse upon the frond, in which are enclosed pedi- 

 cellate, reticulated bodies, called anthers. 



Sjjhcerocarpus consists of a delicate roundish frond, on the 

 surface of which are clustered several cystula?, each of which 

 contains a transpai'ent spherule filled with sporules. 



In Riccia the spherules are not surrounded by cystulse, but 

 immersed in the substance of the frond. 



7. Lichens. 



These have a lobed frond or thallus, the inner substance 

 of which consists wholly of reproductive matter, that breaks 

 through the upper surface in certain forms, which have 

 been called fructification. These forms are twofold ; firstly, 

 shields or scutella, which are little coloured cups or lines with 

 a hard disk, surrounded by a rim, and containing asci, or 



Q 3 



