Plectranthus

Plectranthus verticillatus 3

Plectranthus ecklonii

Plectranthus is a genus of perennial plants and shrubs in the family Lamiaceae, with a wide distribution in the Old World tropics and subtropics, particularly in Africa and Asia, with a few species extending into warm temperate regions as well. The genus includes over 350 species, making it one of the largest in its family. Plectranthus species are known for their attractive foliage, aromatic qualities, and in some cases, traditional medicinal uses. They are commonly used in horticulture as ornamental plants and have been used in traditional medicine for a variety of ailments.

Description

Plectranthus species vary greatly in appearance. They can be low-growing, spreading ground covers, upright shrubs, or herbaceous perennials. The leaves are often highly aromatic when crushed and can be simple, toothed, or deeply lobed, depending on the species. The flowers of Plectranthus are typically borne in spikes or racemes and can be blue, purple, pink, or white. The distinctive feature of Plectranthus flowers is the two-lipped corolla, common to many members of the Lamiaceae family.

Cultivation and Uses

Plectranthus are valued in gardens for their attractive foliage, which may be green, variegated, or purple, depending on the species and variety. They are versatile plants, used in hanging baskets, as ground covers, or as specimen plants. Many species prefer shaded to semi-shaded conditions, making them ideal for understory plantings and for brightening up shaded areas of the garden.

In addition to their ornamental value, several species of Plectranthus have been used in traditional medicine across different cultures. For example, Plectranthus amboinicus, commonly known as Cuban oregano or Spanish thyme, is used in folk medicine for its supposed anti-inflammatory and antimicrobial properties. However, scientific evidence supporting these traditional uses is limited.

Taxonomy and Systematics

The taxonomy of Plectranthus has been complex and subject to revision. It is closely related to the genera Coleus, Solenostemon, and Ocimum, with some species being moved between these genera over time. Molecular phylogenetic studies have helped clarify the relationships within this group, leading to the reclassification of some species.

Conservation

While many Plectranthus species are common and widely cultivated, others are rare and face threats from habitat loss and overcollection. Conservation efforts are necessary to ensure the survival of these species in their natural habitats.

Selected Species

• Plectranthus amboinicus – Cuban oregano, Spanish thyme
• Plectranthus barbatus – Indian Coleus
• Plectranthus scutellarioides – Coleus
• Plectranthus verticillatus – Swedish ivy

Gallery

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See Also

• Lamiaceae – The mint family
• Horticulture
• Traditional medicine

References

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