diaspore

Diaspore is a term used in mineralogy and botany with two primary senses. In mineralogy, diaspore denotes a specific aluminum oxide hydroxide mineral. In botany, a diaspore refers to any plant propagule or dispersal unit released from the parent, including seeds, spores, and fruits, often with structures that aid dispersal.

Mineral diaspore is an oxide-hydroxide mineral with the composition AlO(OH) and is the alpha polymorph of aluminum oxide hydroxide. It is related to other aluminum-based minerals such as boehmite and gibbsite, but forms distinct monoclinic crystals. Diaspore occurs in certain metamorphic rocks and bauxite deposits, where it can appear as colorless to white, pale yellow, or brown crystals or compact masses. It has a Mohs hardness around 5.5–6 and a vitreous to pearly luster. Economically, it is mined as a source of aluminum oxide and processed to produce alumina.

In plant biology, diaspores are the units responsible for dispersal away from the parent plant. A diaspore can be a seed with its coat, a fruit that releases seeds, a schizocarp that splits into mericarps, or even spores. Diaspores may bear adaptations for various dispersal modes, such as wings or hairs for wind, fleshy arils for animals, or hooks for attachment to fur or feathers. The concept is used to study and compare dispersal strategies and germination patterns across species.