Dipterocarpaceae is a family of 16 genera and about 695 known species of mainly tropical lowland rainforest trees. The family name, from the type genus Dipterocarpus, is derived from Greek (di = two, pteron = wing and karpos = fruit) and refers to the two-winged fruit. The largest genera are Shorea (196 species), Hopea (104 species), Dipterocarpus (70 species), and Vatica (65 species). Many are large forest-emergent species, typically reaching heights of 40–70 m, some even over 80 m (in the genera Dryobalanops, Hopea and Shorea), with the tallest known living specimen (Shorea faguetiana) 93.0 m tall. The species of this family are of major importance in the timber trade. Their distribution is pantropical, from northern South America to Africa, the Seychelles, India, Indochina, Indonesia, Malaysia and Philippines. The greatest diversity of Dipterocarpaceae occurs in Borneo. Some species are now endangered as a result of overcutting, extensive illegal logging, and habitat conversion. They provide valuable woods, aromatic essential oils, balsam, and resins, and are a source for plywood. Classification The dipterocarp family is generally divided into two subfamilies: Dipterocarpoideae: the largest of the subfamilies, it contains 13 genera and about 475 species. Distribution includes the Seychelles, Sri Lanka, India, Southeast Asia to New Guinea, and a large distribution in Borneo, where they form the dominant species in the lowland forests. North Borneo (Brunei, Sabah, and Sarawak) is the richest area in the world for dipterocarp species. The Dipterocarpoideae can be divided morphologically into two groups, and the tribe names Shoreae and Dipterocarpeae are sometimes used, but genetic evidence so far does not support this division: Valvate - Dipterocarpeae group (Anisoptera, Cotylelobium, Dipterocarpus, Stemonoporus, Upuna, Vateria, Vateriopsis, Vatica). The genera of this group have valvate sepals in fruit, solitary vessels, scattered resin canals, and basic chromosome number x = 11. Imbricate - Shoreae group (Balanocarpus, Hopea, Parashorea, Shorea). The genera of this group have imbricate sepals in fruit, grouped vessels, resin canals in tangential bands, and basic chromosome number x = 7. A recent molecular study suggests that the genus Hopea forms a clade with Shorea sections Anthoshorea and Doona, and should be merged into Shorea. Monotoideae: three genera, 30 species. Marquesia is native to Africa. Monotes has 26 species, distributed across Africa and Madagascar. Pseudomonotes is native to the Colombian Amazon. A recent genetic study found that the Asian dipterocarps share a common ancestor with the Sarcolaenaceae, a tree family