Plectranthus

Plectranthus is a genus of annual and perennial herbs and some subshrubs in the Lamiaceae family. The family includes well-known cultivated plants like mint, rosemary, sage, salvia and thyme. The generic name is derived from the Greek words plektron meaning an instrument for striking like a lyre pick and anthos meaning flower, referring to the shape of the lower part of the corolla tubes of the flowers.

The stems and leaves are herbaceous, succulent or semisucculent. The simple leaves are opposite or whorled, sometimes aromatic. The leaf margins are often toothed. There are small bracts present, differing from the leaves.

The flowers usually grow in stem-tip spikes or racemes, sometimes branched into panicles. The flowers are solitary or in few-flowered cymes or dichasia (a central flower opening first, flanked by a pair of following flowers). The calyces are two-lipped to sub-equally five-lobed. The two-lipped corollas are tubular at the base, the tubes straight or variably curved or expanded. 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.

The genus 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, many in the eastern part of south Africa. Many Plectranthus species are common garden plants, while a large variety of cultivars and hybrids appear on the market. The plants are also widely used medicinally.

The plant in picture may be Plectranthus ecklonii (Leistner, (Ed.), 2000; Manning, 2009; Pooley, 1998).