1. (n.) One of a class of cellular, flowerless plants, (technically called Lichenes), having no distinction of leaf and stem, usually of scaly, expanded, frond-like forms, but sometimes erect or pendulous and variously branched. They derive their nourishment from the air, and generate by means of spores. The species are very widely distributed, and form irregular spots or patches, usually of a greenish or yellowish color, upon rocks, trees, and various bodies, to which they adhere with great tenacity. They are often improperly called rock moss or tree moss.

2. (n.) A name given to several varieties of skin disease, esp. to one characterized by the eruption of small, conical or flat, reddish pimples, which, if unchecked, tend to spread and produce great and even fatal exhaustion.

acne acne vulgaris algae autophyte bean bracken brown algae climber conferva confervoid creeper dermamycosis dermatitis dermatosis diatom eczema elephantiasis epithelioma erysipelas erythema exanthem fern fruits and vegetables fucus fungus grapevine green algae gulfweed heat rash herb herpes herpes simplex herpes zoster heterophyte hives impetigo itch ivy jungle rot kelp legume lentil leprosy liana lichen primus liverwort lupus lupus vulgaris miliaria mold moss mushroom parasite parasitic plant pea pemphigus perthophyte phytoplankton planktonic algae plant families prickly heat pruigo pruritus psora puffball pulse red algae ringworm rockweed rust saprophyte sargasso sargassum scabies sea lentil sea moss sea wrack seaweed shingles skin cancer smut succulent tetter toadstool vetch vine wort wrack