Piper macropiper Pennant

Gardner, R. O., 2013, Piper (Piperaceae) in New Guinea: the climbing species, Blumea 57 (3), pp. 275-294 : 287

12. Piper macropiper Pennant — Fig. 4c, d, 5a, b, 6a– o

Piper macropiper Pennant (1800) 242; Merr. (1948) 191; Chew (1972) 10; Peekel (1984) 124; R.O. Gardner (2006) 582; Spokes (2007) 236; R.O. Gardner (2010) 12. — Type: Rumphius, Herb.Amb.5 (1747) 46,t. 28, f. 1.

Distribution — Taiwan, throughout Malesia, also Vanuatu, Micronesia, Australia, and the Pacific Ocean region (Wallis & Futuna Is., Samoa).

Habitat — In forest, 0 – 2000(–c. 3300) m altitude.

Notes — As noted in the Introduction, the New Guinea plants under this name are treated here as a species-complex. The four major named variants are as follows. (For types and publication data see ‘Incertae Sedis’. The ‘ List of Collections’ indicates which specimens best fit the circumscriptions here). See Fig. 6 for the variation in leaf size and shape, etc. Additionally, a new large-leaved variety is described further below .

1. Piper macropiper s.str. – Leaves with a unilateral basal lobule, nerves basal or nearly so, glabrous or hirsute to villous; throughout New Guinea incl. Bismarck Archipelogo, 0–1500 (– 2500) m altitude.

2. Piper breviantherum – Leaves relatively short and narrow, without a basal lobule, nerves basal or nearly so, indument usually sericeous; infructescence relatively slender (6–9(–13) by 0.35 cm; central part of New Guinea, from the Star Mts (West Sepik Province) to the Eastern Highlands and Morobe Provinces, (490 –)2000 –2500(–c. 3000) m altitude.

3. Piper novoguineense – Leaves without a basal lobule, nervation usually palmate-pinnate (i.e., usually one or more nerves suprabasal), usually conspicuously red-glandular, glabrous; mainly in Morobe Province (absent from the Bismarck Archipelago and islands of the Milne Bay District), c. 75– 2800 m altitude .

4. Piper rodatzii – Leaves relatively broad, without a basal lobule, nervation palmate-pinnate (uppermost nerve from up to c. 1/3 way along midrib), chartaceous, glabrous; infructescence usually relatively short and stout (to c. 10(–14) by 0.7 cm), bracts with red-brown hairs spreading from near top of bract-stalk for up to c. 0.4 mm beyond margin of head, surface of bract-heads usually glaucous; throughout New Guinea, but apparently rare in the western half of island and in the Bismarck Archipelago and islands of the Milne Bay District, (100 –)500– 2500(–3290) m altitude.

These four variants, if interpreted strictly according to the given characters, take in much of the variation in this complex, but nevertheless a considerable number of specimens cannot be placed into one or the other. This is not to say that all kinds of intermediates occur: a basal lobule, for example, is never found in a rodatzii - or breviantherum -kind of leaf blade.

Another difficulty is that I have seen far too few specimens from West New Guinea to be sure that the last three taxa, all typified on Papuan New Guinea collections, properly represent the range of geographical variation on the island as a whole. For this reason especially, I am not willing to change their taxonomic status (say, to subspecies rank).

Piper macropiper in the strict sense is common in New Guinea up to c. 1500 m, but above that one or other of the three variants seem to predominate. The four can certainly grow in the same general area – I have seen them thus in the Kaironk Valley, Schrader Range, between c. 1500 and 2500 m altitude. Specimens of climbing pipers are sometimes labelled as ‘epiphytes’ or ‘shrubs’. This is most often said about P. rodatzii – I have seen more than a dozen such examples, including two of my own from the Kaironk Valley at 1700 – 2200 m: Gardner 7078, “low epiphyte on relict streamside-forest tree”; 9681, “bushy plant c. 1 m tall on open gully floor in primary forest, perhaps originally climbing?”. Similarly, the label of Grubb & Edwards 187 (Fatima River, 2600 m) has: “Scrambler/climber up lower boles, or, apparently, independent shrub”, and that of Takeuchi 10541 (Bismarck Range, c. 2400 m): “Epiphytic shrublet”. Only a very few specimens elsewhere in the P. macropiper complex (e.g. P. breviantherum, LAE 65805 and P. macropiper s.str., Brass 13976) note such a habit.

Specimens with small dendritic hairs (Fig. 4c), these sometimes accompanied by a typical coarser indument, are from low to moderate altitude (to c. 1000 m) in Morobe District, e.g. Clemens 1257, 1721, 7959, 10824, 40849, Hartley 9765, NGF 26030, Takeuchi 4572) with one from nearby East Sepik District ( LAE 73630). All belong to P. macropiper s.str. Other members of the complex from this region, including the new large-leaved variety described below, lack such hairs.

In addition to the above-described variation in P. macropiper across the island there is one well-marked local variant, newly described as follows.

Figures

Fig. 6 Piper macropiper complex. Fertile-shoot leaves and ripe infructescences (shortened by half in h, k). — a–e: P. breviantherum C.DC.; a. Craven & Schodde 1093, Aseki Patrol District 1600 m; b. Gardner 7068 (AK), Kaironk Valley 1700 m; c. Hoogland & Pullen 6163, Mt Hagen Ra. 2550 m; d. Hoogland & Schodde 6914, Yaki River 2450 m; e. Kalkman 5200, Mt Ambua 2650 m. — f –i: P. macropiper s.str.; f. Brass 13976, Idenberg R. 55 m; g. Brass 25216, Goodenough I. 150 m; h. Brass 31596, Okapa, Eastern Highlands 1950 m; i. Takeuchi 5337, Hunstein Ra.; j. Schodde 1556, Anga Valley 2000 m. — k, l. P. novoguineense Warb.; k. Gardner 9009 (AK), Kaironk Valley 2100 m;l. Pullen 411, Asaro-Mairifutica Divide 2600 m. — m –o. P.rodatzii K.Schum.& Lauterb.; m.Brass 24658, Goodenough I. 1600 m; n. Brass 30479, Mt Wilhelm 2770 m;o.Takeuchi 20143, Porgera 2900 m (all from A except as noted). — Scale bar = 5 cm.