A modified leaf bud that defines members of the Cacti Family. Spines, flowers, or roots can originate from this growth region.

A specialized spin-bearing structure found on the stems of all members of the cactus family. It is basically a modified stem that spines grow out of in place of leaves.

(1) in Cactaceae, a cluster of hairs and/or spines borne at the node of a leafless stem; (2) a space in any reticulated surface, e.g. space between veins. adj. areolate.

[Venation] -- Any small, discretely bounded area. in leaf venation, the space bounded by the finest veins on the lamina, adj. areolate.

A generally circular cluster of spines on members of the cactus family.

A space between the threads of a net, in the family Cactaceae, a cluster of hairs/spines/bristles borne at the node of a leafless stem, in Mimosaceae (for example), a distinct, oblong or elliptical area on the face of a seed, bounded by a fine line. Adj. Areolate. (09 Oct 1997)

A bounded space, as with leaves with net-like venation.