Botany
Small tree or shrub, 2-4 meters high, smooth throughout, branching with slender, solitary, sharp spines 1 cm or less. Leaves are oblong-ovate to elliptic-ovate, 4-6 cm long. Petioles are 1-1.5 cm long. Racemes are short, bearing few flowers, white and fragrant. Petals are 4, oblong, 10-12 mm long. The fruit is almost spherical, 3-5 cm in diameter, yellow, thin-skinned, 10-celled or more.

Distribution
Planted throughout the Philippines in settled areas.

Constituents
Pulp: citric acid, 4.24%; protein, 0.94%; sugar, 0.5%.
Juice: citric acid, 7.67%; vitamin C.

Parts used and preparation
Fruit.

Uses:
Folkloric
Nausea and fainting: Squeeze rind near nostril for irritant inhalation.
Decoction of roots used for dysentery; root-bark as febrifuge.
Mouthwash and gargle for sore throat and thrush.
Externally, fresh juice is used to clean wounds; roasted, for chronic sores.
Others
Flavor: Use juice and grated rind. A pleasant ade.
Substitute for true lemon.
Good source of vitamin C.
As fumigant, steaming brew of leaves under the blanket.

Availability
Commercial cultivation.