=Lecideine=, apothecium usually dark-coloured or carbonaceous and without a thalline margin, 158. =Leprose=, mealy or scurfy, like the old form genera, _Lepra_, _Lepraria_, 191. =Lichen-acids=, organic acids peculiar to lichens, 221 _et seq._ =Lignicolous=, living on wood or trees, 366. =Lirella=, long narrow apothecium of Graphideae, 158. =Mazaedium=, fructification of Coniocarpineae, the spores lying as a powdery mass in the capitulum, 176. =Medulla=, the loose hyphal layer in the interior of the thallus, 88 _et passim_. =Meristematic=, term applied by Wainio to growing hyphae, 48. =Microgonidia=, term applied by Minks to minute greenish bodies in lichen hyphae, 26. =Multi-septate=, term applied to spores with numerous transverse septa, 316 _et seq._ =Murali-divided=, =Muriform=, term applied to spores divided like the masonry of a wall, 187. =Oidium=, reproductive cell formed by the breaking up of the hyphae, 189. =Oil-cell=, hyphal cell containing fat globules, 215. =Orculiform=, see polarilocular. =Orthidium=, supposed new type of fructification in lichens, 192. =Palisade-cells=, the terminal cells of the hyphae forming the fastigiate cortex, 82, 83. =Panniform=, having a felted or matted appearance, 260. =Paraphysis=, sterile filament in the hymenium, 157. =Parasymbiosis=, associated harmless but not mutually useful growth of two organisms, 263. =Parathecium=, hyphal layer round the apothecium, 157. =Peltate=, term applied to orbicular and horizontal apothecia in the form of a shield, 336. =Perithecium=, roundish fructification usually with an apical opening (ostiole) containing ascospores, 158 _et passim_. =Pervious=, referring to scyphi with an opening at the base (_Perviae_), 118. =Phycolichens=, lichens in which the gonidia are blue-green (Myxophyceae), 52 _et passim_. =Placodioid=, thallus with a squamulose determinate outline, generally orbicular; cf. effigurate, 80. =Placodiomorph=, see polarilocular. =Plectenchyma= (=Plectenchymatous=), pseudoparenchyma of fungi and lichens, 66 _et passim_. =Pleurogenous=, borne laterally on hyphal cells; see spermatium, 312. =Pluri-septate=, term applied to spores with several transverse septa, 321 _et seq._ =Podetium=, stalk-like secondary thallus of Cladoniaceae, 114, 293 _et seq._ =Polarilocular=, =Polaribilocular=, two-celled spores with thick median wall traversed by a connecting tube, 188, 340-341. =Polytomous=, arising of several branches of the podetium from one level, 118. =Proper margin=, the hyphal margin surrounding the apothecium, 157. =Prothallus=, =Protothallus=, first stages of hyphal growth; cf. hypothallus, 71. =Pycnidiospores=, stylospores borne in pycnidia, 198 _et passim_. =Pycnidium=, roundish fructification, usually with an opening at the apex, containing sporophores and stylospores; cf. spermogonium, 192 _et seq._ =Pyrenolichens=, in which the fructification is a closed perithecium, 173 _et passim_.