Arboretum Botanical Glossary

Abortive Only partially developed. This feature helps describe plant form, function, or identification.

Abrupt Ending suddenly (or appearing suddenly). This feature helps describe plant form, function, or identification.

Abscissing Separating from its point of attachment. This feature helps describe plant form, function, or identification. Did you know? Autumn leaf drop is controlled abscission. Trees form a clean separation layer at the base of each leaf stalk before the leaf falls.

Accumbent Lying against another organ. This feature helps describe plant form, function, or identification.

Acerose Needle-shaped, as in the leaves of pine or spruce. This feature helps describe plant form, function, or identification. Did you know? Needle-like leaves help conifers conserve water through winter, when frozen soil can make it hard for roots to replace lost moisture.

Achene A dry one-seeded fruit that does not normally split open Did you know? What most people call a sunflower seed is actually an achene. The striped shell is the fruit wall, and the edible kernel inside is the seed.

Acicular Needle shaped. This feature helps describe plant form, function, or identification.

Actinomorphic Radially symmetric, so that a line drawn through the middle at any angle will produce a mirror image on both sides Did you know? Radially symmetrical flowers can often be approached by pollinators from many directions, unlike irregular flowers that guide pollinators to enter one way.

Acuminate Having a tapering point. This feature helps describe plant form, function, or identification. Did you know? Many rainforest leaves have acuminate “drip tips” that shed water quickly, helping reduce fungal growth on constantly wet leaf surfaces.