Noni (Morinda citrifolia, L. 1753)

Identity

Noni (Morinda citrifolia L., 1753), also known as Indian mulberry, is a shrub or small tree in the genus Morinda and the coffee family, Rubiaceae. Carl Linnaeus described the species in Species Plantarum in 1753. Plants of the World Online continues to accept that name. ^{1 2}

The trade name noni is relatively recent. It replaced nono, the original Tahitian name, when fruit juice was introduced to Western markets in the 1990s. Indian mulberry can mislead readers about its botanical relationships: only the surface of the fruit resembles a mulberry. Noni belongs to the Rubiaceae, while true mulberries (Morus) belong to the separate Moraceae family. ¹¹

Recognition

A conical crown and gray-brown bark characterize this tree, which reaches 3–8 m (10–26 ft) tall and sometimes 10 m (33 ft). Its taproot extends deep into the soil, explaining its resistance to drought once established. ⁵

Opposite, glossy leaves are elliptical to lance-shaped, measuring 15–50 cm (6–20 in) long and 5–17 cm (2–7 in) wide. Small tufts of hairs, called domatia, provide a useful identification feature. They occupy the junctions between the midrib and secondary veins on the underside of the leaf blade. ⁵

White, fragrant flowers form rounded heads on stalks 1–4 cm (0.4–1.6 in) long in the leaf axils. The resulting fruit is a syncarp, a fleshy mass formed by the fusion of dozens of small flowers from one head. This explains its surface of polygonal facets. Initially green, the fruit becomes translucent yellow-white at maturity and develops a rancid-cheese smell, earning the English name cheese fruit. ^{5 4}

Useful taxonomy

Several names have been used for this species before Morinda citrifolia became established as its accepted name. The principal synonyms to recognize are:

• Morinda tinctoria Noronha (historical name)
• Morinda citrifolia var. bracteata (Roxb.) Kurz
• Morinda citrifolia var. potteri O.Deg.
• Samama citrifolia (L.) Kuntze

Older botanical and horticultural literature sometimes uses Morinda tinctoria, a name referring to the root's use as a dye. The accepted scientific name remains Morinda citrifolia. ^{1 3}

Habitat and range

Tropical and subtropical Asia through northern Australia form the native range of Morinda citrifolia. Polynesian sailors later carried it across the Pacific as a canoe plant, alongside coconut and pandanus. Its status consequently varies among islands, from native to an ancient introduction or a recently cultivated crop for the juice trade. ^{6 11}

Coastal vegetation and secondary woodland following disturbance are typical habitats. Noni is among the first plants to establish on volcanic ground and poor or saline soils. Its tolerance of these soils explains why some risk assessments rate it as a strong colonizer of degraded ground, despite its native status across most of its range. ^{4 6}

The IUCN conservation assessment places the species in the Least Concern category, with no threat identified across its overall range. ⁷

Life cycle and reproduction

Winter brings no marked dormancy to noni, unlike a temperate tree. In favorable tropical conditions, flowering and fruiting continue almost year-round, without a clear seasonal peak. A plant growing in good conditions may flower and fruit in its first year. ^{4 11}

Seeds are the most common means of propagation. They germinate in 3–9 weeks and remain viable for at least six months in storage. Stem cuttings bring plants into fruit sooner than growing them from seed. ⁴

Uses and risks

Ripe fruit, young leaves and some roasted seeds are eaten. The leaves are rich in protein and vitamin A. More astringent, unripe fruit goes into curries and sambals in South Asia. Ripe fruit is mainly processed into juice because its powerful smell discourages eating it as it is. ^{4 5}

Traditional medicine uses the root for urinary disorders, the bark during childbirth and the fruit for respiratory complaints. These are documented traditional uses and do not amount to clinical validation. ⁴

No toxicity from contact with the plant is documented in cats, dogs or humans. The debate concerns concentrated juice instead. Two hepatitis cases were reported in Austria after prolonged, heavy consumption, while a broader clinical and toxicological study found no evidence of liver toxicity at usual doses. Both interpretations appear in the medical literature, calling for caution with concentrated courses rather than a general warning about the plant. ^{10 9}

Varieties, look-alikes and related plants

Noni has no established horticultural cultivars comparable to the variegated forms of other ornamental plants. Trade descriptions mainly distinguish round-fruited and elongated-fruited plants. These reflect natural differences in shape, without a separate botanical status. ¹

Potential sources of confusion include:

• Morinda tinctoria Noronha, a historical synonym of the same taxon rather than a separate species;
• Morinda royoc, a separate Caribbean species with much smaller fruit;
• true mulberries in the genus Morus, botanically unrelated despite the shared common name.

A rancid-cheese smell at full ripeness, polygonal facets on the syncarp and domatia on the leaf undersides remain the most reliable features for distinguishing Morinda citrifolia from these other plants. ⁵

Main sources

• Plants of the World Online / Kew, Morinda citrifolia L.
• International Plant Names Index (IPNI), Morinda citrifolia L.
• GBIF Backbone Taxonomy, Morinda citrifolia L.
• Plants For A Future (PFAF), Morinda citrifolia
• World Agroforestry Database, Morinda citrifolia species profile
• Pacific Island Ecosystems at Risk (PIER), Morinda citrifolia risk assessment
• IUCN Red List, Morinda citrifolia assessment (de Kok 2024)
• INPN, Morinda citrifolia L. 1753, noni
• West et al., World Journal of Gastroenterology, noni juice is not hepatotoxic
• Hepatotoxicity of NONI juice, report of two cases
• CTAHR / University of Hawaii, Noni resources