Horsfieldia sect. Irya

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Horsfieldia sect. Irya

Description

Flowers pedicelled, not articulated at base, solitary or in loose clusters;

Distribution

Asia-Tropical: Philippines (Philippines present), E Malesia present
Mainly E Malesia (including the Philippines), and one species, H. irya, distributed over almost the whole area of the genus.
(p. 4).

Taxonomy

Almost all of the 40 species of this section have predominantly 2-lobed perianths, with a more or less zygomorphic androecium, because it is laterally compressed or with the anthers at apex incurved from two sides into an apical hollow of the column.

Aberrant are H. olens and H. sepikensis with 3- or 4-lobed perianths, but with the androecium tending to be zygomorphic. Horsfieldia angularis has 2-4-lobed perianths.

Also aberrant are the species of the group of H. clavata, with a 2-lobed perianth but a club-shaped non-zygomorphic androecium.

A few mutually related species from continental SE Asia, placed in section Pyrrhosa, viz. H. longiflora, H. thorelii and H. amygdalina, have (partly) a 2-lobed perianth, and a zygomorphic androecium, especially H. longiflora. They blur the distinction between sections Irya and Pyrrhosa. Section Irya occurs mainly in East Malesia, with only H. irya extending far beyond the main range of distribution of the section. Within section Irya, eight groups of species can be distinguished, a survey of which is given by De Wilde ('1984', 1985: 128).

Citation

WJ. de Wilde – In: Gard. Bull. Sing. p 127
Miq. 1858 – In: Fl. Ind. Bat. p 64
A. DC 1856 – In: Prodr. p 202
Miq. 1858 – In: Fl. Ind. Bat. p 64
Benth. & Hook, f. 1880 – In: Gen. PL. p 137
A.DC. 1856 – In: Prodr. p 202
King 1891 – In: Ann. Roy. Bot. Gard. Calc. p 284