Piper decumanum

Gardner, R. O., 2013, Piper (Piperaceae) in New Guinea: the climbing species, Blumea 57 (3), pp. 275-294 : 283

7. Piper decumanum L. — Fig. 3b , 4b

Piper decumanum L. (1754) 19; Quisumb. (1930) 42; Chew (1972) 6; R.O. Gardner 2006 (581). — Type: Rumph., Herb. Amb. 5 (1747) 45, t. 27.

Distribution — Celebes, Molucca Is., Philippine Is., New Guinea (western part of island, also Sepik and Madang regions); possibly also Micronesia. Habitat & Ecology — In forest, to c. 500 m altitude.

Notes — This species is apparently uncommon in New Guinea, just as it is in the Philippines, where Quisumbing (1930: 42) saw only four collections, all from ‘medium altitude’. The New Guinea specimens I know of – those I have seen myself, and others cited by Chew (1972: 7) – are from the northern side of the island, from the Vogelkop east to Madang Province (NGF 24752, near Aiome).

I have seen only a few specimens of the Micronesian ( Palau Is.) taxon P. hosokawae Fosberg ( P. decumanum var. palauense Hosok. ), none of which have mature infructescences. Their leaves, e.g. as in Takamatsu 1784 (B) are relatively small (c. 18 by 10 cm) compared to those typical of Malesian P. decumanum but are not otherwise unusual. Fosberg & Sachet (1975) do not mention anything distinctive about the female parts of P. hosokawae .

The stomata of P. decumanum leaf are borne singly on low pustules scattered across the blade underside (Fig. 4b).

Figures

Fig. 3 Specimens of Piper species. – a. P. caninum Blume. – b. P. decumanum L. – c. P. insectifugum Seem. – d. P. lessertianum C.DC. (a: NGF 26031, A; b: Darbyshire & Hoogland 8124, A; c: Brass 23997, A; d: Cuming 1343, BM).