Apical - Apex, the uppermost part, tip.

Arborescent- Tree-like in character.

Areole- A small specialized area where spines are produced.

Axil - Angle at which a leaf joins its stem.

Clavate - Club-like or club shaped.

Diurnal - During the daytime.

Indefinite - Slight, barely noticeable.

Globus - Spherical, round.

Globular - Round, spherical.

Glochida - A cluster of many small bristles, usually mound shaped.

Hydroponic - Growing in a water/nutrient solution without soil.

Ramified - To divide into branches.

Stomates- An epidermal pore for gas exchange.

Tubercles - A stem projection bearing an Areole

Tuberculate- Having tubercles

Umbricated - Having a cup-like depression.

Vegetative reproduction - Propagation by cuttings, grafts.