Spiraeopsis
Description
Shrub or small to large trees.
Leaves opposite and decussate, imparipinnate (commonly 2-4-jugate) or trifoliolate;
Stipules interpetiolar, one pair per node, ± orbicular with apex rounded and somewhat curled back, or reniform, ± caducous.
Inflorescences axillary, paniculate thyrses, many-flowered, branching at the proximal nodes opposite, then often soon becoming alternate, the main axes often strongly dominant and flowers borne singly or in small fascicles on relatively short, lateral axes.
Flowers 4-5-merous (except gynoecium), petaliferous, ± sessile or shortly pedicellate, bisexual but markedly protandrous;
Sepals valvate, ovate to triangular, attached to hypanthium at their greatest width, not connate, glabrous above.
Petals elliptic with the base attenuate, to obovate, ± equal in length to sepals, fugaceous.
Stamens with filaments thin, subulate, glabrous and anthers broadly cordate, the connective shortly extended.
Ovary syncarpous, superior, carpels 2-5, hairy, each bearing a glabrous, cylindrical style;
Fruit dehiscent, capsular, the valves boat-shaped, as many as carpels, coriaceous in central part and thin at the edges (lateral extensions of the endocarp), the margins (placentae) of each valve often partially detaching to form a persistent replum, the margin on each side of a valve detached from valve at base but connate with margin of adjacent valve, then distally free from both valve and adjacent margin, and finally reunited with valve at apex;
Seeds several, small, elongate, with narrow, sub-equal wings at each end.
Distribution
Asia-Tropical: Maluku (Maluku present); New Guinea present ‒ present; Philippines (Philippines present); Sulawesi (Sulawesi present), New Britain present, New Ireland present, Solomon Islands present
Solomon Islands and Malesia: Philippines, Sulawesi, Moluccas, New Guinea, New Britain&New Ireland. Six species, one of which is widespread; the others are confined to New Guinea.
Morphology
2. In the open flowers, the alternisepalous stamens are slightly longer and less deeply impressed in the outer edge of the disc than are the alternipetalous ones. In bud however, the alternipetalous stamens are distinctly longer and apparently more advanced than the alternisepalous ones.
3. Protandry is marked in most flowering collections. Usually all flowers in one inflorescence, and often most inflorescences on one tree, are at approximately the same stage, thereby giving the impression that the species are dioecious.
1 In addition to the stellate hairs, shortly stalked, orbicular, glandular, peltate hairs occur in this genus (see p. 60-62). They are especially noticeable in Spiraeopsis celebica and S. clemensiae, where they are most obvious on the lower surface of the leaves, but they may occur also on the upper leaf surface, on vegetative branchlets, on the inflorescence up to the pedicel and outer surface of the calyx, and sometimes amongst the hairs on the ovary. In herbarium material they are usually bright orange and appear ± spherical at low magnification. They are referred to in the key and descriptions as glandular trichomes or glandular hairs.
Citation
L.M. Perry 1949 – In: J. Arnold Arbor. 30: 145
Hutch. 1967 – In: Gen. Flow. Pl. Dicot.: 11
Engl. 1928 – In: Nat. Pflanzenfam., ed. 2: 241
Hutch. 1967 – In: Gen. Flow. Pl. Dicot.: 10
Engl. 1928 – In: Nat. Pflanzenfam., ed. 2: 244
Miq. 1857 – In: De Vriese, Pl. Ind. Bat. Orient.: 155
Baill. 1871 – In: Adansonia: 152
Boerl. 1890 – In: Handl. Fl. Ned. Ind.: 443
Blume 1858: p. 31. – In: C. Muell., Walp. Ann. Bot. Syst. 5: ‘Dichynchosia’.