200 



REPRODUCTION 



The three last named types of sporophores represent Nylander's section 

 of arthrosterigmata. Steiner has followed Nylander in also arranging the 

 various forms into two leading groups. The first, characterized by the 

 secondary branch or "sterigma," he designates "exobasidial "; the second, 

 comprising the three last types in which the spores are borne directly on 

 the cells of the sporophore or on very short processes, he describes as " endo- 

 basidial." Steiner also introduces a new term, fulcrum, for the sporophore. 

 The pycnidia in which these different sporophores occur are not, as a 

 rule, characteristic of one family. Peltigera type is found only in one family 

 and the Cladonia type is fairly constant in Cladoniae, but " Psora " pycnidia 

 are found on very varying lichens among the Lecideaceae, Verrucariaceae 

 and others. The Sqnamaria type with long bent spores is found not only in 

 Squamaria (Gliick's Placodium) but also in Lecidea, Roccella, Pyrenula, etc. 

 Parnielia type is characteristic of many Parmeliae and also of species of 

 Everma, Alectoria, Platysma and Cetraria. The Sticta type occurs in Gyro- 

 phora, Umbilicaria, Nepliromium and Lecanora as well as in Sticta and in one 

 species at least of Collema. To the Physcia type belong the pycnidia of most 

 Pliysciaceae and of various Parmeliae, and to the closely related Endocarpon 

 type the pycnidia of Endocarpon and of XantJioria parietina. 



c. PERIFHYSES AND STERILE FILAMENTS. In a few species, Roccella 

 tinctoria,Pertusariaglobulifcra,z\.c.,s\iort one-celled sterile hyphae are formed 

 within the spermogonium near the ostiole, towards which they converge. 



They correspond to the periphyses in the peri- 

 thecia of some Pyrenolichens, Verrucaria, etc. 

 (described by Gibelli 1 as spermatiophores); they 

 are also present in some of the Pyrenomycetes 

 (Sordaria, etc.), and in many cases replace the 

 paraphyses in function when these have broken 

 down. Sterile hyphae also occur, towards the base, 

 mingled with the fertile spermatiophores (Fig. 

 1 14). These latter were first described and figured 

 by Tulasne 2 in the spermogonia of Ramalina 

 fraxinea as stoutish branching filaments, rising 

 from the same base as the spermatiophores but much longer, and frequently 

 anastomosing with each other. They have been noted also in Usnea bar- 

 bata and in several species of Parmelia, and have been compared by Ny- 

 lander 3 to paraphyses. They are usually colourless, but, in the Parmeliae, 

 are often brownish and thus easily distinguished from the spermatio- 

 phores. It has been stated that these filaments are sometimes fertile. Similar 

 sterile hyphae have been recorded in the pycnidia of fungi, in Sporocladus 

 (Hendersonia) lichenicola (Sphaeropsideae) by Corda* who described them as 

 1 Gibelli 1866. 2 Tulasne 1852. 3 Nylander 1858. * Corda 1839. 



Fig. 114. Sterile filaments in 

 spermogonia of Leddea fus- 

 coatra Ach. much magnified 

 (after Lindsay). 



