Trees or shrubs, rarely epiphytes and stranglers. Leaves opposite and decussate or very rarely whorled (outside Malesia), simple, trifoliolate or imparipinnate, usually petiolate; Stipules interpetiolar, one pair per node, elliptic, ovate, orbicular to subreniform, often constricted at the base, often caducous in adult foliage; a pair of opposite stipules often salverform, amplexicaul and ± persistent in juvenile foliage; Inflorescence racemose; Flowers unisexual or bisexual, hypogynous or somewhat perigynous, petaliferous, pedicellate, 4(-5)-merous or commonly 5-merous outside Malesia except for gynoecium. Petals 4(-5), sometimes fugaceous (outside Malesia), usually elliptic, ovate or obovate, constricted at the base, rounded or irreg-ularly emarginate at the apex, membranous, often ciliolate. Stamens twice as many as calyx lobes; Fruit a septicidal or septifragal capsule dehiscing from the apex; Seeds elliptic in outline and circular in transverse section, minutely sculptured, usually comose with a tuft of hairs at each end or sometimes hairs arising all over.
Africa: absent Asia-Tropical:, Malaya (Peninsular Malaysia ‒ present); Thailand (Thailand ‒ present) Australasia: Latin America: present islands of the western Indian Ocean: present mainland Asia: absent southern Pacific: present
Widespread in Latin America (c. 80 species), the islands of the western Indian Ocean (c. 30 species) and the southern Pacific (c. 25 species), and throughout Malesia (c. 17 species), though represented by few species in the western part. Absent from Africa, mainland Asia (except Peninsular Malaysia and Thailand) and Australia.
Bernardi (1961, 1963, 1964) divided the genus into six sections. A phylogenetic study by Bradford (1998) confirmed the utility of five of these, with minor modifications. In Malesia, most species belong to sect. Fasciculatae Hoogland & H.C. Hopkins, which is largely Malesian but extends into the Pacific as far as Fiji, and a single Malesian species, W. croftii, belongs to sect. Leiospermum (D.Don) Engl. (sect. Racemosae of Bernardi), which is predominantly Pacific and found on most of the high islands or island groups south of the equator, including New Caledonia and New Zealand, as far E as the Marquesas. Sections Fasciculatae and Leiospermum can be readily distinguished from each other by the structure of the inflorescence. In addition, the flowers are usually inserted on the axes of the racemes singly in sect. Leiospermum and in small fascicles in sect. Fasciculatae (exception in W. descombesiana).
5. Two collections from Irian Jaya are highly unusual in having flowers arranged not in racemes but appearing directly from woody stems, i.e. cauliflorous. 3. Flowers and fruits within Malesia are remarkably uniform in structure. Dimensions are included for all species but they provide few useful characters. 2. Within Malesia, Weinmannia appears to be predominantly dioecious, individuals bearing morphologically unisexual flowers. Exceptions include W. descombesiana, W. furfuracea and some populations of W. fraxinea, which have morphologically hermaphrodite flowers. Evidence for polygamodioecy (or subandroecy?, with male and hermaphrodite flowers on the same plant) is rare in Malesia, but this condition appears to occur sometimes in W. eymaeana, W. fraxinea and W. urdanetensis. 1 Weinmannia is the largest genus in the family, containing about half the species. With the exception of W. fraxinea, most Malesian species have a rather limited geographical distribution and Sulawesi, with seven species, has the highest number of taxa of any island within our area. The number of taxa recognised within Malesia depends partly on the circumscription of W. fraxinea, a widespread, variable species, and its satellites. In addition to the named taxa described here, unplaced material from Sulawesi and Irian Jaya may represent a handful of additional species (see Hopkins 1998). 4. The flowers are typically white, cream or pale pink, or occasionally bright pink, with a slight sweet fragrance. The disc lobes may be either pale and inconspicuous or dark and contrasting with the pale corolla, and at least in some species they are nectari-ferous. A high proportion of female or hermaphrodite flowers in any raceme produces fruit. Young stems and leaves are often conspicuously tinged red.
L. - in Humbert, Fl. Madag. 93. 1965: 3
H.C. Hopkins, Adansonia. 1998: 5, 43, 67, 107
L. - in Adansonia n.s. 1963: 404
J.C. Bradford - in Ann. Missouri Bot. Gard. 1998: 565
Bernardi - in Candollea. 1963: 285
Engl. - in Nat. Pflanzenfam., ed. 2. 1928: 250
Bernardi - in Candollea. 1961: 123
L. - in Bot. Jahrb. Syst. 1964: 126, 185
Kuntze - in Revis. Gen. Pl. 1891: 228
Hutch. - in Gen. Flow. Pl. Dicot. 1967: 9