Osbeckia is a genus of herbs and shrubs found across the Old World tropics, from Africa through South and Southeast Asia to parts of Australia. It also carries an interesting historical footnote: it was named after Pehr Osbeck, a Swedish naturalist and student of Carl Linnaeus.
Quick facts. Family: Melastomataceae. Range: tropical Africa, Asia and parts of Australasia. Habitat: open grassland, forest edges, stream margins and roadsides. Growth form: bristly herbs to small shrubs. Flowers: pink to purple, four or five petals.
A historical name
Osbeck sailed to China in the eighteenth century as a ship's chaplain and collected plants, insects and other natural history specimens, which he sent back to Sweden. Linnaeus honoured him with the genus name. Plant names often preserve this kind of history; see reading a botanical name for how to decode them.
Appearance
Osbeckia plants are typically bristly or hairy, with opposite leaves showing the characteristic three to five longitudinal veins. The flowers are usually pink to purple, opening wide in sun and displaying the curved stamens of the family. They are followed by small urn-shaped capsules full of tiny seeds.
Habitat
Many Osbeckia species prefer open, sunny, moist places. They are common in grassland, along tracks and on cleared land, and some thrive in the burned or grazed landscapes of the monsoon tropics. Others occur in forest margins and along streams. This tolerance for open habitats sets them apart from the shade-loving herbs described in Sonerila and Bertolonia.
Pollination
Like many melastomes with pore-opening anthers, Osbeckia flowers are visited by bees that vibrate the flower to release pollen. The flowers often have two kinds of stamens, one set that supplies pollen to feed bees and another that deposits pollen onto the bee's body. See the anatomy of a melastome flower for the detail.
Cultivation
A few species are grown in warm climate gardens for their flowers. They generally want:
- Full sun to light shade.
- Acidic, moisture-retentive soil that still drains well.
- Warmth, with protection from frost.
- Regular pruning to keep a tidy shape.
They are not widely available, and anyone planting outside their native range should check whether the species is considered weedy in their region.
Traditional uses
Several Osbeckia species appear in ethnobotanical records from Asia and Africa. These records are interesting as cultural history, but they should not be read as proof of medical benefit; see Melastomataceae in traditional medicine for a careful look at the evidence.
Takeaway
Osbeckia is a widespread Old World representative of a family that is mostly Neotropical, and it shows that melastomes can thrive in open, sunny habitats as well as in forest shade.