Coralline

Coralline (Corallina officinalis), a limy seaweed, exceedingly common on British coasts, where it adds much to the beauty of the rocky pools. It is a hardy perennial plant, and envelops the rocks and almost any object between tide marks with its beautiful branching fronds. In spring it appears as a thin crust, with a fresh delicate pinkish or purplish colour. With the increasing sunshine it grows into prettily jointed and branched tufts, spreading like brushwood over the surface of the rock. Its purple colour increases in depth, till the plant grows old and begins to die; then the brightness pales, and the limy incrustation finally remains as a white skeleton. The purple colour soon fades on exposure; a bright white light is produced by holding a piece of the alga in a candle flame; an unpleasant smell lingers for years about the dried specimen. The coralline was formerly regarded as an animal, 'since all lime,' Linnaeus said, 'is most truly a product of animals.' But neither for this, nor for its supposed medicinal (vermifuge) virtues was there any warrant. Technically, the common coralline, along with a few other species, forms a genus of alga in the family Corallineæ, the section Rhodospermeæ, and the group Florideæ. Melobesia is an allied form of similar stony character. It is sometimes used for manuring fields, and is said to have been one of the principal constituents in the mortar of Iona cathedral. The name coralline is sometimes extended vaguely to certain Zoophytes or Hydroids (q.v.). See Landsborough's British Seaweeds, Harvey's Phycologia Britannica, Johnston's British Sponges and Corallines.