Hapteron, aerial organ of attachment, [94], [122].
Haustorium, outgrowth or branch of a hypha serving as an organ of suction, [32].
Helotism, state of servitude, term used to denote the relation of alga to fungus in lichen organization, [38], [40].
Heteromerous, fungal and algal constituents of the thallus in definite strata, [13], [68], [305] et passim.
Hold-fast, rooting organ of thallus, [109], [122] et passim.
Homobium, interdependent association of fungus and alga, [31].
Homoiomerous, fungal and algal constituents more or less mixed in the thallus, [13], [68], [305] et passim.
Hymenial gonidia, algal cells in the hymenium, [30], [314], [315], [327].
Hymenium, apothecial tissue consisting of asci and paraphyses; [cf. thecium], [157].
Hymenolichens, lichens of which the fungal constituent is a Hymenomycete, [152-154], [342].