areoles - circular clusters of spines on a cactus. Flowers bud at an areole and new stems branch from an areole.

cladode - a flattened stem that looks like a leaf.

cuticle - the outer layer of the epidermis, which is often waxy

floccose - covered with short hairs, like the areole of some cacti.

glochids - tufts of short, barbed spines that are found at the areoles of opuntia cacti.

glabrous - lacking hairs, usually applied to an old areole or a flower scale.

glaucous - covered with a wax-like layer, liek the cuticle of many cactus species.

globose - shaped like a globe (or sphere).

parastichy - the spiral line (invisible) of the pattern of the areoles on a cactus.

pericarpel - the tissue of the upper part of the flower stem, the receptable, and the lower part of the pistil.

spine - a sharp, pointed, modified leaf found in areoles of cacti.

stamen - the male reproductive parts of a flower. It consists of the filament and the anther.

stigma - part of the pistil, the female reproductive tissue of a flower.

succulent - a plant that has fleshy and juicy tissues, like cacti, sedums, aloes, and yuccas.

sulcus - a groove.

xeric - xeric environmental conditions are ones that are very dry.

xerophyte - a plant that is adapted to very dry conditions (like deserts and the emergent level of the rainforest). Succulents, bromeliads and cacti are xerophytes.