Hypophloeodal, thallus growing within the bark, [78], [364].
Hypothallus, first growth of hyphae (proto- or pro-thallus) persisting as hyphal growth at base or margin of the thallus, [70], [257] et passim.
Hypothecium, layer below the thecium (hymenium), [157].
Intricate cortex, composed of hyphae densely interwoven but not coalescent, [83].
Isidium, coral-like outgrowth on the lichen thallus, [149-151].
Lecanorine, apothecium with a thalline margin as in Lecanora, [158].
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.]