_c._ PERIPHYSES AND STERILE FILAMENTS. In a few species, _Roccella tinctoria_, _Pertusaria globulifera_, etc., short one-celled sterile hyphae are formed within the spermogonium near the ostiole, towards which they converge. They correspond to the periphyses in the perithecia of some Pyrenolichens, Verrucaria, etc. (described by Gibelli[720] 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. 114). These latter were first described and figured by Tulasne[721] 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 barbata_ and in several species of _Parmelia_, and have been compared by Nylander[722] to paraphyses. They are usually colourless, but, in the _Parmeliae_, are often brownish and thus easily distinguished from the spermatiophores. 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[723] who described them as paraphyses, and also in _Steganosporium cellulosum_ (Melanconieae). These observations have been confirmed by Allescher[724] in his recent work on _Fungi Imperfecti_. Keiszler[725] has described a _Phoma_-like, pycnidium parasitic on the leprose thallus of _Haematomma elatinum_. It contains short slender sporophores and, mixed with these, long branched sterile hyphae which reach to the ostiole and evidently function as paraphyses, though Keiszler suggests that they may be a second form of sporophore that has become sterile. On account of their presence he placed the fungus in a new genus _Lichenophoma_. E. SPERMATIA OR PYCNIDIOSPORES _a._ ORIGIN AND FORM OF SPERMATIA. Lichen spermatia arise at the tips of the sterigmata either through simple abstriction or by budding. In the former case—as in the _Squamaria_ type—a delicate cross-wall is formed by which the spermatium is separated off. When they arise by budding, there is first a small clavate sac-like swelling of the end of the short process or sterigma which gradually grows out into a spermatium on a very narrow base. This latter formation occurs in the _Sticta_, _Physcia_ and _Endocarpon_ types. Nylander[726] has distinguished the following forms of spermatia: 1. Ob-clavate, the broad end attached to the sterigma as in _Usneae_, _Cetraria glauca_ and _C. juniperina_. 2. Acicular and minute but slightly swollen at each end, somewhat dumb-bell like, in _Cetraria nivalis_, _C. cucullata_, _Alectoria_, _Evernia_ and some _Parmeliae_, frequently borne on “arthrosterigmata.”