4io 



DIVISION III. MODE OF LIFE OF THE FUNGI. 



and in Sticta, and Scytonema or Stigonema in Stereocaulon. In many forms, for 

 example in Sticta and Stereocaulon, the Nostocaceae are localised in peculiarly shaped 

 branched or convex outgrowths from the thallus, which have received the name 

 of cephalodia. 



The Alga is firmly attached to the adjoining hyphae ; where the structure is a dense 

 pseudo-parenchyma as in Endocarpon it is squeezed in between the hyphae ; where it 

 is filamentous and lacunose the hyphae send out branches, which attach themselves 

 firmly to the algal cells ; it not unfrequently happens that the hypha comes into contact 

 with the new cells formed by division of the algal cells, and in that case it sends out 

 small branches from the point of contact which embrace the Alga closely in the way 



FIG. 175. Thelidium minutulum. A perithecium on the thallus ; a groups of Algae, FIG. 176. v d CystocoUus the- 



M the part of the thallus without Algae spreading in the substratum, f the perithecium nuts, Thw. a extremity of a branch 



cut through the middle, represented diagrammatically and slightly magnified. B a group seen from without. 4 a similar one 



of Algae with hyphae growing round them, magn. 480 times. After Stahl. in optical longitudinal section ; x the 



Algae ; a and h from preparations 

 made transparent by Schulze's solu- 

 tion, r, d transverse sections. 



e , fCcenogonium Linkii, Ehrb. ; 

 c slender branch of the thallus with a 

 ateral branch in optical longitudinal 

 section, /"transverse section through 

 a stronger branch. After Schwen- 

 dener. a, b, c, d, e magn. 390, f 300 

 times. 



described above in the case of germ-tubes (Fig. 167 E). The Stigonema which is 

 peculiar to the cephalodia of Stereocaulon furcatum is seized by the hyphae in the 

 same way as in Ephebe which will be noticed further on. 



2. There are a considerable number of Lichens, which are reckoned in 

 descriptive works among the heteromerous species and agree with them on the whole 

 in the manner of their growth, but which depart from the scheme of the heteromerous 

 thallus in having no differentiation of a rind, and having the Algae scattered among 

 the hyphae* Of this kind are the marine fruticose Lichinae which have Calothrix 

 scopulorum, Ag. for their Alga 1 , the frondose Pannarieae with Algae frcm the groups 

 of Nostoc and Scytonema, a large number of Graphideae of different genera, 



1 See Kny in Sitzgsber. d. Naturf. Freunde 1874, and Bornet in Ann. d. So. Nat. ser. 5, XVII. 



