The fruit resembles a mandarin orange; is round, oblate, or obovate, of irregular surface, the base becoming furrowed and slightly necked with age, the apex rounded or faintly nippled; 1 3/4 to 2 1/2 in (4.5-6.25 cm) wide, 1 5/8 to 2 1/4 in (4.1-5.7 cm) high; peel is reddish-orange, with large oil glands, thin, easily removed; pulp has limelike aroma, is deep-orange, in 8 to 10 segments having tender walls and separating readily from each other; melting, very juicy; flavor exceedingly sour but suggestive of orange; there may be 6-18 seeds, small, green within.
The tree is fast-growing, more or less spreading, reaching 15 to 20 ft (4.5-6 m); has short thorns; the flower buds and petals are purple-tinted. It is more cold-tolerant than the lime and in California has endured freezes better than the lemon. Unfortunately, it is highly subject to scab. It bears abundantly, from November through winter, and the fruits remain on the tree in good condition. It is a casual dooryard tree in Florida and a minor commercial fruit tree in California. Until the late 1930s, it was much used in Brazil and Argentina as a rootstock but trees budded onto it proved to be short-lived It is grown to some extent in Australia and the Hawaiian Islands, rarely in Trinidad where it was introduced from Montserrat in 1920.
In India, mandarin orange juice is improved by adding 20-40% Rangpur juice. Small, whole fruits can be candied or pickled, but the Rangpur is not fully appreciated until it is made into marmalade. This product is superb and rivals or excels that made from the sour orange.
2) Kusiae or kusiae lime is presumably a form of the Rangpur though it is even more limelike in aroma. It is believed to have evolved in India where virtually identical fruits are called nasaran and nemu tenga. Hawaiians believe that early Spanish settlers planted it on Kusiae, or Strongs Island, in the Caroline Islands of Micronesia. In 1885, Henry Swinton introduced it into Hawaii where it was described and pictured by Gerrit Wilder in 1911. Budwood was taken from Wilder's garden in Honolulu to the Citrus Experiment Station at Riverside, California, in 1914.
The fruit is oval, oblate or round, furrowed and sometimes faintly necked at the base, the apex rounded or with a slight pointed nipple; 1 1/2 to 2 1/2 in (4-6.25 cm) wide; the peel is deep-yellow with prominent oil glands, medium-thick to thin, leathery, easily removed; pulp is honey-yellow, in 8 or 9 segments having tender walls; melting, somewhat less acid than the true lime and not so rich in flavor; contains 6 to 10 small seeds; the abundant juice is colorless, transparent.
The tree is vigorous, of bushy habit, branched to the ground, but reaching 10 to 20 ft (4.5-6 m) in height; has only a few small thorns and oval to lanceolate leaves; new growth is pale-green; sends up many root sprouts, forming thickets. It is generally grown from seeds and seedlings may be less thorny and seedy than their parents; can be grafted onto sour orange or other non-sprouting citrus rootstocks to avoid root suckers. Fruiting begins in 1 1/2 to 3 years and the tree is nearly everbearing and prolific. In Hawaii, 11-year-old trees have borne 2,000 fruits, nearly 200 lbs (90.5 kg) per tree. The Kusiae lime is cold-tolerant, immune to withertip but prone to scab and root-rot. It is a common dooryard fruit tree in Hawaii and also grown in Trinidad, little-known elsewhere.
3) Otaheite, or Otaite, orange, or Otaheite Rangpur, formerly known as C. otaitensis Risso & Poit. (syn. C. taitensis Risso), is now thought to be a non-acid form of the Rangpur. Its origin is unknown. It was introduced into France from Tahiti by way of England in 1813; was being grown in Paris by the botanist Noisitte in 1915. It was catalogued by a San Francisco nurseryman in 1882.
The fruit is oblate to spherical, 1 1/2 to 2 in (4-5 cm) wide, furrowed and rounded or slightly necked at the base, the apex rounded or with a flat nipple; peel is orange with small oil glands; thin; pulp is orange, in 7 to 10 segments, juicy, slightly limelike in aroma and flavor but bland with scarcely any acidity; seedless, or with 3 to 6 small, abortive seeds.
The tree is a dwarf, spreading, thornless, with oblong to elliptic, finely-toothed leaves having narrowly-winged petioles; the new growth is deep-purple; flowers are fragrant and purple outside. Grown from cuttings or airlayers, the tree is widely sold in the United States as a potted "miniature orange", especially in the Christmas season when it bears flowers and fruits concurrently.