Mesosphaerum pectinatum


Mesosphaerum pectinatum is a species of flowering plant in the family Lamiaceae commonly called comb bushmint. It is native to the tropical Americas, as well as being naturalized in parts of Africa, Asia, and Australia.

Description

This species is an annual or short-lived perennial herb growing tall, with the lower stems becoming softly woody with age.
The leaves are carried on stalks long. The blades are ovate to narrowly ovate, long and wide. They are sparsely hairy on the upper surface and paler beneath, where they are usually softly white-felted. The leaf tips are blunt, the bases truncate, and the margins finely and irregularly scalloped to toothed.
The inflorescence is terminal and often branched. Flowers are usually arranged in dense, horizontal, comb-like clusters, sometimes paired on a shared stalk, though looser arrangements also occur. The lower bracts resemble small leaves and become progressively smaller towards the tip; the bracteoles are narrow, bristle-like, and about long.
The calyx is about long at flowering and enlarges to in fruit, with dense hairs inside the throat. The corolla is whitish to pale mauve and approximately long.

Distribution and habitat

Mesosphaerum pectinatum′s native range extends from Mexico, Florida, and the West Indies in the north through Central America to Bolivia and Brazil in the south.
It is also naturalized in the Andaman Islands, Angola, north-east Argentina, Assam in India, Benin, Botswana, Burundi, Cape Verde, the Central African Republic, the Comoros, the Republic of the Congo, the Democratic Republic of the Congo, Equatorial Guinea, Eritrea, Ethiopia, Fiji, Gabon, Guinea, Hawaii, the Ivory Coast, Java, Kenya, Malawi, the Marianas, Mozambique, New Caledonia, New Guinea, the Philippines, Queensland in Australia, Rwanda, Samoa, South Africa, South Sudan, Taiwan, Tanzania, Togo, Uganda, Vanuatu, Zambia, and Zimbabwe. In Africa, it is long established and is often considered native.
It grows in hotter, wetter environments, often on disturbed ground, where it can become especially weedy.