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Leaf and flower. Copyright CSIRO

Flowers and immature fruit. Copyright CSIRO

Cotyledon stage, epigeal germination. Copyright CSIRO

10th leaf stage. Copyright CSIRO

Hyptis suaveolens

Family

Lamiaceae

Botanical Name

Hyptis suaveolens (L.) Poit.

Poiteau, P.A. (1806) Annales du Museum National d'Histoire Naturelle 7: 472. Type: ?.

Synonyms

Ballota suaveolens L., Systema Naturae ed. 10: 1100(1759), Type: ?.

Common name

Mint Bush; Hyptis; Horehound; Wild Spikenard

Weed

Stem

Flowers and fruits as a herb but frequently grows into a shrub.

Leaves

Leaf bearing twigs +/- 4-angled, twigs and leaves very aromatic when crushed. Leaf blades about 3-5 x 2-4 cm. Pale glands visible on both the upper and lower surfaces of the leaf blade. Septate hairs present on the upper surface of the leaf blade.

Flowers

Inflorescence a 2-5-flowered cyme on peduncles which are usually longer than the petioles. Calyx about 5-5.5 mm long, lobes linear, all parts of the outer surface of the calyx clothed in long white hairs and short glandular hairs or spherical hyaline stalked glands. Corolla about 4-5 mm long, outer surface clothed in white hairs. Anthers pink, red or purple, borne obliquely on the filaments, filaments hairy. Style glabrous, inserted in the centre between the lobes of the ovary.

Fruit

Fruit resembles a capsule but actually consists of a persistent ribbed calyx about 8-10 mm long and contains 1-4 nutlets. Nutlets flattened, narrowly oblong, about 1.2-4 mm long. Nutlet surface +/- smooth when dry but producing a dense mass of fine white hairs when boiled in water.

Seedlings

Cotyledons about 9-12 x 7-11 mm, purple on the underside, petiole slightly shorter than the cotyledon blade. Stout septate hairs present on the upper surface of the first pair of leaves. At the tenth leaf stage: leaf blade about 30-35 x 25-30 mm, stout septate and fine simple hairs present on the upper surface.

Distribution and Ecology

An introduced species originally from tropical America but now pantropic, which has become naturalized in WA, NT, CYP, NEQ and southwards as far as south-eastern Queensland. Altitudinal range from near sea level to 750 m. Usually grows on heavily grazed open forest areas but also found in monsoon forest and vine thickets.

Natural History

This species may have medicinal properties. (http://squid2.laughingsquid.net/hosts/herbweb.com /herbage/A13720.htm)