6. Morinda citrifolia Linnaeus, Sp. Pl. 1: 176. 1753.
海滨木巴戟 hai bin mu ba ji
Morinda bracteata Roxburgh.
Evergreen shrubs or small trees, to 5 m tall, often fleshy; branches subquadrangular, glabrous. Leaves opposite or solitary opposite an inflorescence; petiole 5-20 mm, glabrous; blade fleshy, drying papery, elliptic-oblong, elliptic, or ovate, 10-25 × 5-13 cm, glabrous and shiny on both surfaces, base acute or acuminate, apex acute to obtuse; secondary veins 5-7 pairs, with pubescent domatia; stipules interpetiolar, free or shortly fused to petioles, broadly triangular to ovate, 4-16 mm, obtuse or rounded. Inflorescence solitary and leaf-opposed; peduncle 1-1.5 cm; head 1, oblong to subglobose, 5-10 mm in diam., many flowered; bracts absent. Flowers with hypanthia partially fused, distylous. Calyx glabrous or puberulent; limb subtruncate to truncate, 0.2-0.5 mm, sometimes in 1 to numerous flowers of a head with 1(-3) calycophylls, these white, narrowly elliptic to oblanceolate, 5-16 mm, obtuse to acute. Corolla white, funnelform, outside glabrous; tube ca. 15 mm, densely villous in throat; lobes 5, ovate-lanceolate, ca. 6 mm. Drupecetum white, irregularly ovoid to subglobose, 2.5-5 cm. Drupes not distinguishable individually. Fl. and fr. year-round.
Flat land on seashores, sparse forests; below 100 m. Guangdong, Hainan, Taiwan [?Cambodia, India, Indonesia, Japan (Bonin and Ryukyu Islands), Malaysia, Myanmar, Papua New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; N Australia, Solomon Islands; introduced in tropical America and Pacific islands].
The distinctive form called Morinda bracteata has well-developed white calycophylls that give the plants a markedly different appearance and may function in pollination, but these two forms have generally been considered conspecific. Nelson and Elevitch (Noni, 42-43. 2006) noted that plants with bracteate inflorescences produce smaller fruit and that the cultivated plants with variegated leaves are called M. citrifolia ‘Potteri.’ Both of these forms are found in Taiwan (e.g., Yang & Chuang 11410, MO, "citifolia" form; Yang & Chuang 12060, MO, "bracteata" form). The fruit of this species are edible (though not particularly palatable) and said to have medicinal and/or tonic value; they are sold by natural food vendors under the name "noni" or "nona." This species is increasingly widely cultivated, as detailed by Nelson and Elevitch (loc. cit.).