Samanea saman, the rain tree, is a huge umbrella-shaped tree from tropical America whose leaflets fold up at night and on cloudy days. The Tamil name thoongu moonji, “sleeping face”, comes from that habit. It was planted along Indian roads and estates for its enormous shade, and its sweet pods are good fodder for cattle.
- Botanical name
- Samanea saman (Jacq.) Merr.
- Family
- Fabaceae
- Tamil
- Thoongu moonji
- Hindi
- Vilayati siris
- Parts used
- Shade, Pods (fodder)
- Habit
- Umbrella rain tree; siris is A. lebbeck
- Last updated
- 2026-10-26
How to recognise Rain tree
It grows into a massive tree with a broad, dome-shaped crown wider than it is tall, on a short, thick trunk.
The leaves are twice-pinnate, with oval leaflets that fold together at dusk and in rain.
Flowers are pink and cream powder-puffs made mostly of long stamens, appearing in the dry season.
The pods are long, thick and dark brown, with sticky, sweet pulp around the seeds. Siris, Albizia lebbeck, has flat, papery, rattling pods.
Traditional use of Rain tree
Planting
Rain trees were planted along roads, in plantations as shade for tea and coffee, and in parks in Kolkata, Bengaluru and Chennai.
Indian planting history
Fodder
Fallen pods are collected and fed to cattle and goats.
Indian farm practice
Modern notes on Rain tree
As a nitrogen-fixing legume it enriches the soil beneath it. Its rapid growth makes it a useful agroforestry tree.
Its wide, heavy branches need space and regular checks near roads and buildings.
Rain tree safety
The pods are fodder. Old trees can drop heavy limbs.
Ecology and sourcing
It is native to Central America and northern South America and has been planted throughout the tropics.
The folding leaves let rain reach the ground beneath, so grass grows under it, which is one explanation for the name rain tree.
It spreads from seed and can be invasive in some Pacific islands.
Related plants
Also in Fabaceae
Questions about Rain tree
Why rain tree?
Its leaves fold before rain and at night.
What older names does Samanea saman go by?
Albizia saman and Pithecellobium saman.
Is Rain tree siris?
No. Siris is Albizia lebbeck.
How big does Rain tree get?
Its crown can spread wider than a large house, often thirty metres or more.
Sources
- Samanea saman (Jacq.) Merr. — Plants of the World Online, Kew (search) (accessed 2026)
- Wikidata item Q259500 (Samanea saman)
Educational page about a plant. It is not medical advice, not a diagnosis, and not an offer to sell. Traditional use is historical. If you need care, ask a licensed clinician. Questions: hello@meevamed.com.