Plectranthus

The genus Plectranthus is large, comprising about 300 aromatic herbs, also some shrubs in tropical and warm regions in the Old World. About 45 species are indigenous to southern Africa.

The Lamiaceae family includes well-known cultivated plants like mint, thyme, sage and rosemary. Many Plectranthus species are common garden plants, while a large variety of cultivars and hybrids appear on the market.

Plectranthus flowers usually grow in spikes or racemes. They two-lipped corollas are tubular at the base, the tubes straight or curved. The lower lip is usually boat-shaped, the upper one shorter and four lobed. There are four stamens, sometimes only two functional ones. The style lies with the stamens on the lower lip. The stigma is two-lobed. The fruit is a one-seeded nutlet (Manning, 2009; Leistner, (Ed.), 2000).