Note:  Do not rely on this information. It is very old.

Raphides

Raphides, a Greek word meaning "needles," applied strictly, in botany, to the slender crystals of calcium oxalate, belonging to the Oblique system, which occur in bundles chiefly in the cells of Monocotyledons. The term is, however, often extended to any crystals occurring within the plant, those grouped in spherical clusters being distinguished as sphecraphides.