Combava

Combava is a shrub of the Papeda subgenus native to the Indonesian archipelago.
It is now widespread from Sri Lanka to the West Indies.

The medium-sized fruits (10cm), with their acidic, slightly green pulp, are very bumpy and often very numerous.
They are remarkable and appreciated for their zest, rich in oils with powerful fragrances dominated by lemongrass.
All parts of the fruit, and even the infused leaves, are used in Asian cuisine.

The tree is elegant, with a fairly slender trunk and branches, and typical Papeda two-lobed foliage.
With the right pruning, it can be kept in a pot or a temperature-controlled greenhouse.

Note:
Cold hardiness is not sufficient for outdoor planting in Switzerland.

References:
https://idtools.org/tools/1076/index.cfm?packageID=1179&entityID=8421
https://citrusvariety.ucr.edu/crc2454