tomentosa

Tomentosa is a Latin-derived epithet used in botanical nomenclature to indicate a plant surface that is densely covered with short, matted, woolly hairs, a condition known as tomentose indumentum. The word comes from tomentum, Latin for a woolly covering, and is the feminine form of the adjective, agreeing with feminine or feminized genus names in species designations.

In scientific naming, tomentosa is applied to species whose leaves, stems, fruits, or other organs present a conspicuous dense hairiness. This trait can help distinguish taxa in the field and in herbarium specimens, particularly when other morphological features are similar. The dense indumentum often gives a pale or grayish appearance and a soft, woolly feel to the touch, which can be evident on both surfaces of leaves or along the stems.

Tomentose surfaces are contrasted with other terms that describe plant hairiness, such as pubescent (fine, soft hairs), pilose (longer hairs), villose (long, soft hairs), or glabrous (lacking hairs). The presence and distribution of tomentose areas can be variable within a species, influenced by age, environmental conditions, or tissue type, and thus may be more pronounced in juvenile growth or under specific habitats.

The epithet tomentosa is widely used across plant groups and is one of several morphological descriptors employed to convey visible characteristics in species names. It provides a concise signal to researchers about a key diagnostic feature, aiding identification and comparison among related taxa.