Mesosphaerum pectinatum (L.) Kuntze

Kuntze, C.E.O. (1891) Revisio Generum Plantarum 2: 525.

Comb hyptis; Hyptis, Comb

Usually flowers and fruits as an erect herb but may reach 4 m.

Leaf bearing twigs +/- 4-angled, twigs and leaves aromatic or not aromatic when crushed. Leaf blades about 2-8 x 1-4.5 cm. Hairy on both leaf surfaces, usually denser on underside.

Inflorescence a 6-15-flowered cyme. Calyx about 2.5 mm long, 10-ribbed, lobes linear, all parts of the outer surface of the calyx clothed in hairs. Corolla white to pale blue or pink-tinged, 3-3.5 mm long.

Fruit resembles a capsule but actually consists of a persistent ribbed calyx about 8-10 mm long and contains 1-4 nutlets. Nutlets oblong, to 2 mm long. Nutlet surface smooth when dry.

Cotyledons about 3-5 x 4-6 mm, reniform. First pair of leaves opposite, margins crenate with about 3-5 teeth, upper and lower surfaces of the leaf blade hairy. At the tenth leaf stage: crushed plant parts emit an odour like that of mint (Mentha sp.) leaf margin irregularly serrate. Leaf petiolate. Stem square in transverse section.

An introduced species originally from tropical America, which has become naturalised in NEQ and CEQ. Altitudinal range near sea level. Usually grows along roadsides, under powerlines and other disturbed areas.

A serious tropical weed.

Hyptis pectinata (L.) Poit., Ann. Mus. Par., vii: 474 (1806). Nepeta pectinata L., Systema Naturae Edn. 10, 2: 1097 (1759), Type: Browne s.n., Jamaica.