l99sl ESSIG:PALMS OF BISMARCKARCHIPELAGO Principes,39(3), I995, pp. 123-129 A Checklistand Analysisof the Palmsof the Bismarck Archipelago FneoenlcrB. Essrc Institutefor Systematic Botany, Department ofBiology, (Jniuersity ofsouth Florida, Tampa, FL 33620 This analysisof the palm flora of the Bismarck them. However,surprisingly few New Guineapalms Archipelago, although certainly incomplete, is have crossedthe small gap. The Solomon Islands intended both as a practical guide to the palms, begin officially with Bougainville, some 120 miles and as a small contribution to the phytogeography east of New Ireland, with only a few very small of the region. The Bismarck Archipelago is a sub- islandslying betweenthe two archipelagos.A num- stantial chain of islands off the north-east coast ber of palms have apparently migrated from the of New Guinea, and is part of the independent Solomonsto the Bismarck Archipelago. nation of Papua New Guinea. The chain itself is Most palm fruits in the western Pacific region "U," bent into I Iying on its side just south of are fleshy and rather heavy, and are presumably the equator. The two large islandsof New Britain dispersedonly short distancesby animals (Nypo and New Ireland form the bulk ofthe archipelago, and Cocosare obvious exceptions).Some genera but both sidesof the U-shapedchain extend west- with large fruits, such as Orania, are absentfrom ward in strings of small islands. The chain ter- the Bismarck Archipelago,although abundantand minates on the north side with Manus Island (the diverse on New Guinea and some of the islands Admiralty Islands), and on the south side with a to the southeast.Even genera with smaller fruits seiies of small volcanic islandslying closely along (e.9., Calamus, Gulubia, Gronophyllum, the north coast of New Guinea (Fig. l). Hydr i as t ele, Caly p t r oc alyx, H et er os p at h e, and. The largest of the islands, New Britain, is rug- Cyrtostachys) are each representedby only one ged and mountainous, consisting of over 36,000 or two speciesin the islands. On the other hand, squarekilometers, with peaks tp to 2,250 meters somegenera with large fruits(Ptychococcus, Acti- in elevation. The geology is complex, large areas norhytis) are found in the Bismarck chain and in of raisedlimestone alternating with extensiveareas the Solomons. of volcanic rock and a number of active volcanos. Genera with endemic speciesin the Bismarck New Ireland is much smaller and for the most Archipelago are Ptychosperma, Gronophyllum, part quite narrow, but the southeastern end is Heter os p athe, Hydr iastele, Caly p tr ocalyx, Cyr - broad and mountainous, with peaks over I,800 tostachys, Physolcentia and, Clinostigrna. The meters high. The higher elevationson both islands first six genera are widely distributed in New sustain montane forest and some of the unique Guinea. The last two are distributed through the elementsof the palm flora. Solomon Islands and down to but not in New Moore ( I 969b) consideredthe palm flora of the Caledonia. The remaining genera found in the Solomon Islands to be primarily an extension of region are represented by common, widespread that of New Guinea, with some contribution (Cli- species. nostigma, Physolcentia) from the ancient Pacific Genera for:nd on New Guinea but lacking in flora that survives primarily in New Caledonia.As the Bismarck Archipelago arei Bora.ssus,Bras- one would expect, the palms of the Bismarck siophoenix, Corypha, Daemonorops, KorthaL Archipelago show an intermediate character sia, Linospadix, Pinanga, Sommieria, andPiga- between those of New Guinea and those of the fetta. Most of these genera are fairly restricted Solomon Islands. New Britain is separated from in their distribution, even in New Guinea, and not New Guinea by only 83 kilometers, the volcanic suitably positioned for migration eastward. Kor- Umboi Island serving as a stepping stone between thalsia, however, is widespreadand common in t24 PRINCIPES [Vor.. 39 Manus I. EF New Hanovert] Long I. ""rr.,t"Ut\ (Solomon Is.\.-) "Q) (\1 Map of the Bismarck Archipelago. New Guinea, and its fruits are small. It \ryouldnot annotations(as well as some by Moore), and my be surprising eventually to find it somewherein mention of them in my Palm Flora of New Guinea the Bismarck Archipelago. (Essig1977), regrettablymay have lead to erro- Rhopaloblaste and,Liuistona are found in both neousreports of the occurrenceof Drymophloeus N_ewGuinea and the Solor4onIslands, but seem in the Bismarck Archipelago (as in Moore L969b, to be lacking from the Bismarck Archipelago. Hay 1984). Drymophloeus is found only in west- Moore's(1969b) indicationthat Liuiston@occurs ernmost West Irian, skips over the remainder of here appearsto have been in error, although one New Guinea,and reappearsin the SolomonIslands, would certainly expect it. Several speciesof this assuming one accepts the inclusion of Burret's genus occur in New Guinea, including L. wood- gentlrisR ehdero p hoenix in D ryrnop hloeus (Moore of fordii Ridley, which also occurs in the Solomon 1969a).The tremendousgeographic separation Islands(Tulagi, Esa'ala).To date, however, I have these two parts of the genus, and the fact that seen no collectionsfrom this region. the characters by which Drymophloeus is distin- One genusthat has diversified among the islands guished from the other genera of the Ptychos- is Ptychospenna) a large genus centered in New permatinae are primitive for the alliance as a Guinea, and representedby two endemic species whole, suggest that the issue should be further in the Bismarck Archipelago,and at leastone more examined. in the Solomon Islands. None of these seems to One final observation-These islandswere set- have any closerelatives in New Guinea, however, tled by seafaringpeoples many centuriesago, and with P. hentyi being an unusual endemic in New there has undoubtedly been much interaction Britain, andP. gracile appearingto be most closely among the peoplesof the islandsand New Guinea related to Solomon Island and Australian species. since then. We must take into consideration' Ptychosperma subgenusActinophloeus, on the therefore, the possibility of human introduction other hand, is lacking altogether from the islands, and cultivation of some of the palms. Ptychococ- although it is widespreadin New Guinea. cus and Caryota, for example, have very hard 'When "wood" I first encountered specimensof Pty- used by the local people throughout the chosperma hentyi, I assignedthem to Drymo- region for bows,spearheads and a variety of other phloeus based on the elongate peduncles of the purposes(pers. obs.).It is quite possiblethat early inflorescence,the broadly cuneate, apically con- settlers or traders brought seedsof these species vex leaflets,and the apparently globoseseeds. My with them. In both genera mentioned, the single r9951 ESSIG:PALMS OF BISMARCKARCHIPELAGO species present in the Bismarck Archipelago 9a. Palmswithstiltroots.. .....I0 appears to be indistinguishablefrom speciesdis- 9b. Palms without stilt root. : : : . : : : : . : : : : : : . : : Il tributed broadly through New Guinea and into the I0a. Fruits dark purple; seedsharply angled; montane for- Islands. est,NewBritain . ...... Physokentiaaaia Solomon Similar interpretations can be l0b. Fruits redi seedsterete in cross-section;montane for. argued for Cocos nucifera, Metroxyl.on sagu, est, New Ireland . .Clinostigma collegarum Areca catechu, andAreca macrocalyx, as lla, Palms massive, clumping, producing a massive inflo. all are ' of economic importance. rescence at the apex of the trunk; leaf bases with sinuous spiny ridges . .. Metroxylon sagu I lb. Palms of moderatedimensions, or with solitary tnmks, Synopsisof the Palmsof the producing inflorescencesin sequencefrom the axils .; BismarckArchipelago of the leaves;leaf basessmooth . ...... 12 I2a. Pinnae conspicuouslytoothed or ragged at the tips l3 The only previous work on the plant life of the I2b. Pinnae acute or briefly notched at the tips . .. 13 BismarckArchipelago was that of Peekel(1984), l3a. Pimae induplicate; chntering palrns with coarse fibrous leafbases;crownshaft lacking . -, Arenga microcarpa a German Catholic priest who resided on New l3b. Pinnae reduplicate; solitary or clustering palms with Ireland for many years. A truly enlightenedindi- non-fibrousleafbases; crownshaft present ....... 18 vidual, Peekel studied not only the botany of New I 4a. Staminate flowers soft, with long, pointed, loosely closed Ireland, but also the language and cultuie of the petals,mature when first exposed;fruit terete in cross- people there. We are indebted to Peekel for the section. .......... rJ I 4b. Staminateflowers hard, bullet-shaped,maturing slowly indigenousnames from New Ireland and much of after exposure of the inflorescence; seed Slobed in the ethnobotanicalnotes included in the followins cross-section,at least when immature .......... 16 list. I5a. Small,clustering palms .. .......Hydriastele kasesa ISb. Tall, solitarypalms; restricted to ManusI. ....... Kry ro Gronophyllum manusii rHE SpECTES I6a. Pinnae broad. wedge-shaped,apically "oru"*l .eed subteretein cross.section..... Ptychosperma hentyi la. Leaves palmate; small, solitary palms of the forest I6b, Pinnae lanceolate, apically oblique to concave; seed undergrowth ....... Licuala lauterbachii clearly SJobed in cross-section lb. Leaves pinnate or bipinnate; habits various . .. 2 17a. Fruits less than 2,5 cm long, with thin, fibrous endo- Leavesbipinnate; large solitary palms producing inflo- carp . .. .. Ptychospermagracile rescencesfrom