Sonerila is one of the Old World's most interesting melastome genera. It is mostly made up of small, delicate herbs of damp, shaded places, and it has a feature that makes its flowers easy to recognise: they typically have three petals, where most melastomes have four or five.
Quick facts. Family: Melastomataceae. Range: tropical Asia, including India, Sri Lanka, Southeast Asia and southern China. Habitat: moist, shaded forest floors, stream banks and rock faces. Size: well over a hundred species. Flowers: usually pink, three-petalled.
A genus of small, local species
Sonerila contains well over a hundred species of herbs and small subshrubs. Many species have tiny ranges. The Western Ghats of India and Sri Lanka, for example, hold a number of species found nowhere else, often restricted to particular hills or forest patches. This makes the genus important for studies of endemism and conservation in biodiversity hotspots.
New species continue to be described, often from specimens collected in forest remnants that few botanists have surveyed. See how new species get described for how that process works.
Spotting a Sonerila
- Flowers: three pink or purplish petals, often arranged in a one-sided, curving cluster.
- Leaves: opposite, often with the family's characteristic longitudinal veins. Some species have leaves that are dark green with rows of silvery spots or bands, which gives a jewelled look.
- Habit: soft, fleshy stems, often reclining and rooting where they touch damp soil.
The most commonly seen species in cultivation are the spotted-leaf forms, such as plants sold under the name Sonerila margaritacea, which are grown for their foliage in terrariums.
Ecology
Sonerila species grow where humidity is high and light is dim. They prefer rock crevices, mossy banks and streamside soils, where moisture is constant. Because of this tight dependence on microclimate, they are sensitive to forest clearance, drying of streams and changes to the canopy.
Growing Sonerila
The care requirements resemble those of other small melastome herbs such as Bertolonia.
- Keep humidity high and air still, in a closed or semi-closed terrarium.
- Provide gentle, indirect light.
- Use a light, moisture-retentive, slightly acidic mix and avoid soggy soil.
- Keep temperatures mild and stable.
- Propagate from stem cuttings, which often root readily in humid conditions.
Because these are delicate plants, sourcing matters. Look for plants raised in nurseries, and avoid any offered as wild-collected.
Why Sonerila matters
The genus illustrates a pattern repeated across the family: a few widespread, adaptable species and a long tail of narrow endemics. Those narrow endemics are vulnerable, and many are poorly documented. Herbarium specimens, discussed in herbaria: where melastome species are preserved, are often the only record of when and where a species was found.