BY F. HILTON CROWE.

Botany and zoology are replete with the evidences of how versatile a performer is Nature. At Castillo de San Marcos (now Fort Marion National Monument), the ancient coquina stronghold built by the Spaniards to guard Saint Augustine, Florida, she has played expertly in the role of interior decorator.

The photograph at the right shows the arched ceiling and one of the aged gray walls of a room in the fort. That room, unlike some of the others, is not grim and bleak and bare; it is fresh with a verdant tapestry of living lace: the Southern Maidenhair fern.

Maidenhair (Adiantum Capillus-Veneris) is characterized by the glossy, lustrous, hairlike branches of the frond which give to the fern its popular name. Its resplendent pinna are divided in turn into pinnules or sections with scalloped or crenate edges. Under these tips, hidden within tiny chests of fiber, lie almost microscopic spores. Unaided by human hands, the tiny life germs broke free from the mother pinna and, borne by the wind, found a haven in the porous rock of which the fortress was constructed in the years following 1672. Seepage of moisture down through the walls and arches of the casemate has kept the plants alive because the minute chemical "laboratory" of the organism requires only moisture and a small amount of sunlight to enable it to manufacture food from the calcium of the shelly stone.

During the recent work program designed by the National Park Service to preserve the ancient casemates, or bomb-proof chambers, by waterproofing the roof, the needs of the maidenhair were not forgotten. The section of the roof covering the fern room was allowed to remain porous so that moisture could continue to percolate through the walls and feed the delicate fern.

Most of the quarter-million-odd visitors recorded each year at Fort Marion pause to ask questions when they reach the fern room, and many hundreds attempt, without spectacular success, to photograph the dainty fronds which sway almost continuously in their shaded retreat. ---F. Hilton Crowe.