Durian trees are relatively large, growing up to 25–50 metres (80–165 ft) in height, depending on species. The leaves are evergreen, opposite, elliptic to oblong and 10–18 centimetres (4–7 in) long. The flowers are produced in three to thirty clusters together on large branches and the trunk, each flower having a calyx (sepals) and 5 (rarely 4 or 6) petals. Durian trees have one or two flowering and fruiting periods each year, although the timing of these varies depending on species, cultivars and localities. A typical durian tree can bear fruit after four or five years. The durian fruit, which can hang from any branch, matures in about three months after pollination. Among the thirty known species of Durio, so far nine species have been identified to produce edible fruits : D. zibethinus, D. dulcis, D. grandiflorus, D. graveolens, D. kutejensis, D. lowianus, D. macrantha, D. oxleyanus and D. testudinarum. However, there are many species for which the fruit has never been collected or properly examined, and other species with edible fruit may exist
Durio graveolens, also known as red-fleshed durian. The colour of its flesh ranges from orange to bright red.D. zibethinus is the only species commercially cultivated on a large scale and available outside of its native region. Since this species is open-pollinated, it shows considerable diversity in fruit colour and odour, size of flesh and seed, and tree phenology. In the species name, zibethinus refers to the Indian Civet, Viverra zibetha. There is disagreement regarding whether this name, bestowed by Linnaeus, refers to civets being so fond of the durian that the fruit was used as bait to entrap them, or to the durian smelling like the civet.Durian flowers are large and feathery with copious nectar, and give off a heavy, sour and buttery odour. These features are typical of flowers which are pollinated by certain species of bats while they eat nectar and pollen. According to a research conducted in Malaysia during 1970s, durians were pollinated almost exclusively by cave fruit bats (Eonycteris spelaea). However, a more recent research done in 1996 indicated that two species, D. grandiflorus and D. oblongus, were pollinated by spiderhunters (Nectariniidae) and that the other species, D. kutejensis, was pollinated by giant honey bees and birds as well as bats.