Leaf scales. Coloured scanning electron micrograph (SEM) of leaf scales (trichomes) on Spanish moss, or greybeard (Tillandsia usneoides). This is not a moss but an epiphytic bromeliad, a plant which lives on other plants but does not harm them. As it has no roots in the ground, this plant uses these wide scales, called shields, to extract moisture from the air. The shields also prevent the plant from drying out in dry conditions. Spanish moss grows on trees from the southern USA south to Argentina. Magnification: x100 at 6x7cm size. x160 at 4x5"~SQUARE"