High in the Andes, above the continuous forest and below the permanent snow, lies a landscape of tussock grasses, cushion plants and low shrubs known as the páramo. Among the most characteristic shrubs here are species of Brachyotum.
Quick facts. Family: Melastomataceae. Range: the Andes, from Venezuela through Colombia and Ecuador to Peru and Bolivia. Habitat: páramo and upper montane forest, commonly 2,500 to 4,000 metres. Growth form: compact evergreen shrubs. Flowers: nodding, bell-shaped to tubular.
A genus built for altitude
Brachyotum includes roughly fifty species, most of them confined to the Andes. They range from knee-high shrubs to plants a few metres tall. The environment they live in is demanding: intense ultraviolet light, large daily temperature swings, frequent frost at night, strong winds and thin, often waterlogged, acidic soils.
Several features help them cope:
- Small, thick leaves. Compared with the large, thin leaves of lowland melastomes, páramo species have small, leathery leaves that lose less water and resist wind damage.
- Hairs and bristles. Fine hairs on leaves and stems trap a layer of still air, which buffers against cold and drying wind.
- Compact growth. Dense, low branching keeps the plant within the warmer layer of air near the ground.
- Evergreen habit. There is no time to regrow a whole canopy during a short, cold growing season, so the leaves persist.
The flowers
Brachyotum flowers hang down, usually in shades of yellow, orange, red or purple, with a bell or tube shape. This shape and colour is consistent with visits from hummingbirds and other nectar-feeding birds, and with bees in some species. As in most melastomes, the anthers release pollen through pores, and many species display different stamens with different functions within the same flower.
Role in the ecosystem
In páramo and high cloud-forest margins, shrubs like Brachyotum provide shelter for insects and small animals and nectar for pollinators during seasons when few other plants are in bloom. Páramo ecosystems are also important water regulators, soaking up rain and mist and releasing it slowly, which supplies many Andean cities and farms.
In the garden
A few Brachyotum species have been trialled in mild temperate gardens, for example in the British Isles and the Pacific Northwest, where winters are cool and wet rather than severely cold. They generally need acidic, well-drained but moist soil, shelter from harsh winds, and protection from hard freezes. They do not tolerate hot, dry summers well, since their native habitat stays cool all year.
Why it matters
Because páramo species occupy narrow elevation bands, they are sensitive to climate change. As temperatures rise, suitable habitat can shift upslope, and plants at the summit of a mountain have nowhere further to go. Brachyotum is therefore a useful group for studying how mountain plants respond to warming. See melastomes of the Andes for more.