Annonaceae in the Western Pacific : geographic patterns and four new species

Abstract. The taxonomy and distribution of Pacific Annonaceae are reviewed in light of recent changes in generic delimitations. A new species of the genus Monoon from the Solomon Archipelago is described, Monoon salomonicum I.M.Turner & Utteridge sp. nov., together with an apparently related new species from New Guinea, Monoon pachypetalum I.M.Turner & Utteridge sp. nov. The confirmed presence of the genus in the Solomon Islands extends the generic range eastward beyond New Guinea. Two new species of Huberantha are described, Huberantha asymmetrica I.M.Turner & Utteridge sp. nov. and Huberantha whistleri I.M.Turner & Utteridge sp. nov., from the Solomon Islands and Samoa respectively. New combinations are proposed: Drepananthus novoguineensis (Baker f.) I.M.Turner & Utteridge comb. nov., Meiogyne punctulata (Baill.) I.M.Turner & Utteridge comb. nov. and Monoon merrillii (Kaneh.) I.M.Turner & Utteridge comb. nov. One neotype and four lectotypes are designated. The geographic patterns exhibited by nine native Annonaceae genera, that range in the Pacific beyond New Guinea, are discussed.


Introduction
There has been considerable change in the classification of the large tropical family the Annonaceae over recent decades (Chatrou et al. 2012).An area for which this has been particularly marked is the islands of the Pacific north and east of New Guinea.In this region (here taken as the Solomon Archipelago and beyond but not including the Bismarck Archipelago) the realignment of genera and the correction of faulty generic placements have led to name changes in a relatively high proportion of the native species.This reorganisation has bearing on the geographical ranges of a number of genera which have not yet been analysed in detail.The purpose of this study was to investigate the distribution patterns of the native Annonaceae genera in the Western Pacific.The currently accepted scenario for colonisation of this region by Annonaceae genera is one of dispersal from West Malesia to East Malesia, Australia and the Pacific, probably in the Miocene (5-23 Ma), during periods of relatively low sea levels resulting in larger and more closely spaced stepping stones that facilitated such migration.This has been inferred from molecular phylogenies and estimated divergence times in the Annonaceae genera Meiogyne (Thomas et al. 2012), Pseuduvaria Miq.(Su & Saunders 2009) and Uvaria (Zhou et al. 2012).Johnson et al. (2013) suggested that the Xylopia species in New Caledonia may include pre-Oligocene relict taxa.However, in general, Xylopia shows the typical pattern of west to east migration probably involving long-distance dispersal (Stull et al. 2017).
In working on the Pacific material, we realised that there are undescribed species present.So our first aim was to produce a list of species present in the region incorporating the recent nomenclatural changes.We have included the description of four new species, three from the region and one from New Guinea.

Material and methods
The study was based on the relevant literature (Guillaumin 1948;Whitmore 1966;Foreman 1972;Smith 1981;Hancock & Henderson 1988) on the flora of the region and recent revisionary works (cited below) plus specimens in the herbarium of the Royal Botanic Gardens Kew (K).We focussed on genera that extend out into the Pacific beyond New Guinea and its near neighbours.In other words, those that reach at least the Solomon Archipelago (Solomon Islands plus Bougainville which is politically part of Papua New Guinea).As only a few extra species are involved, we also include the species from Micronesia.Cananga (Dunal) Hook.f.& Thomson was excluded from the analysis, as the only representative, Cananga odorata (Lam.)Hook.f.& Thomson, has a history of cultivation in the region and has probably been spread by human introduction (Florence 2004).Annona L. was also omitted for the same reasons.
For conservation assessments, the IUCN (2012) criteria were followed.The Extent of Occurrence (EOO) and Area of Occupancy (AOO) were calculated using the Geocat software (http://geocat.kew.org; see Bachman et al. 2011).The EOO was estimated as the surface of the smallest convex polygon encompassing all locations but where large areas of unsuitable habitat occur (especially germane to island groups), then EOO was estimated by using an online Google Maps Area Calculator (https://www.daftlogic.com/projects-google-maps-area-calculator-tool.htm).The AOO was calculated as the sum of the surfaces of 2 km × 2 cells in which the species occurred (e.g., 4 km 2 × number of cells occupied by the species).A 2-km grid size was used in order to be able to apply the thresholds defined by the IUCN, as recognised in the guidelines.

Results
Based on our survey of herbarium specimens and the literature, excluding Cananga, nine genera (Drepananthus, Goniothalamus, Huberantha, Meiogyne, Monoon, Polyalthia s. str., Popowia, Uvaria, and Xylopia) as currently recognised and represented by at least 40 species, are found in the Western Pacific beyond New Guinea.Of these, the occurrence of Monoon in the Solomon Archipelago seems not to have been previously reported.We describe two new species of Monoon and two new species of Huberantha.

Monoon in Melanesia
The generic name Monoon was recently taken up again (Xue et al. 2012) for a group of 60-70 species, mostly formerly included in Polyalthia, Enicosanthum, Cleistopetalum and Woodiellantha.The genus has not been monographed, but in listing the species that they recognised in the genus and making many new combinations, Xue et al. (2012) included three species from New Guinea: Monoon chloranthum (Lauterb.& K.Schum.)B.Xue & R.M.K.Saunders, Monoon chloroxanthum Miq. and Monoon polycarpum (Burck) B.Xue & R.M.K.Saunders.In going through the material of Monoon from New Guinea and the Solomons, it became obvious to us that more species were present than these three.One group of specimens with very thick, fleshy petals clearly differed from the described taxa which all have relatively thin petals.The fleshy-flowered group included a New Guinea gathering distributed as Polyalthia pachypetala Diels.However, this name appears never to have been published.The thick-petaled specimens from the Solomons differ significantly from the New Guinea material, so we describe both as new.There is possibly a third species with fleshy petals represented by a specimen from New Britain (NGF 22441), but the material is too limited to describe.
We consider these species to belong in Monoon due to the possession of eucamptodromous leaf venation, decurrent insertion of lateral nerves to the midrib, uniovulate carpels and (where available) relatively soft seeds with an irregular longitudinal groove and lamelliform endosperm quartering the seed in transverse section.

Diagnosis
Differs from the other described species of Monoon from Melanesia in its relatively short and thick flower pedicels and broadly ovate, thick fleshy petals.Differs from Monoon salomonicum sp.nov. in having a distinctly asymmetric leaf base and subsessile monocarps.

Etymology
We maintain the epithet chosen by Diels which reflects the thick petals of the new species.

Description
Tree to at least 10 m tall, 10 cm dbh.Twigs drying blackish or dark brown, longitudinally wrinkled, sometimes with small brown, round or oval lenticels; youngest parts with pale brown tomentum, otherwise glabrous.Leaves chartaceous, drying grey-brown above, brown or grey-brown below with darker brown midrib and lateral nerves, midrib slightly sunken above in dry leaves, prominent below, lateral nerves more or less flush above, raised below, glabrous or sparsely hairy along midrib above, glabrous or with scattered hairs on nerves below, lamina ovate-elliptic to obovate, 7-21 × 2.5-8 cm, apex shortly acuminate, base obtuse to cordate, distinctly asymmetric with one side more markedly lobed, lateral nerves 9-12 pairs, arching forward and running more or less parallel before looping obscurely just within margin, intersection of laterals with midrib decurrent, tertiary venation scalariform, distinct from both surfaces in dry leaves; petioles 4-6 mm long, drying blackish, minutely wrinkled, sometimes with brown hairs.Inflorescences axillary, solitary, single-flowered.Flowering pedicel 7-15 mm long, 1-1.5 mm diameter, widening distally, drying dark brown, wrinkled, sparsely hairy; medial bract broadly ovate ca 1 × 2 mm, hairy outside, glabrous within; calyx connate forming 3-pointed cup, each sepal broadly ovate 2 × 4-5 mm, sparsely short brown hairy outside, glabrous, drying blackish, within; outer petals broadly ovate ca 13 × 10 mm, base truncate, apex acute, drying ca 1 mm thick in upper portion, externally verruculose but obscured by dense brown or pale adpressed tomentum, similar inside except for glabrous region near base; inner petals ovate-lanceolate ca 10 × 7 mm, brown tomentose except for basal part of adaxial surface which dries black, sometimes longitudinally grooved distally and warty proximally, otherwise smooth; stamens many in 4-5 rows, ca 1 mm long, connective apex polygonal; carpels many.Fruiting pedicel to 25 mm long, 2 mm thick, widening distally, drying brown, longitudinally striate, very short pale hairs, monocarps ca 10, drying dull dark brown with very short brown tomentum, ellipsoidal ca 2.5 × 1.5 mm, subsessile.Seeds 1.

Distribution and habitat
Lowland forest in New Guinea (Fig. 2).

Conservation status
Currently known from only three collection sites in Indonesian New Guinea: one on the south of the central range just to the north of Tanah Merah, one on the north coast near Sarmi and the other in the Vogelkop coastal area near Manokwari.All three sites appear to be relatively undisturbed when using Google Earth imagery, or close to undisturbed areas, and it is to be expected that Monoon pachypetalum sp.nov. is found in lowland forest throughout Indonesian New Guinea.Using the known collection data, it is difficult to accurately estimate the EOO using GeoCat because of large areas of unsuitable habitat (the high elevations of the central range and the Cendrawasih Bay).An approximate EOO is 55,400 km 2 (based on two polygons of 49,000 + 6,400 km 2 excluding unsuitable habitat and encompassing the collection sites) which is outside any of the IUCN threat criteria.However, the AOO is 12 km 2 which falls within the EN category and the species is also known from only three locations.However, because the habitat in the environs of the collection localities appears to be intact, we are currently unable to know if the quality of the habitat is declining, etc., and thus the species does not fulfil the two criteria for a geographic range assessment.We thus estimate Monoon pachypetalum sp.nov.as Near Threatened (NT) noting that further collection locations are needed, as well as better observations of population size and habitat quality.

Distribution and habitat
Papua New Guinea (Bougainville) and the Solomon Islands (Fig. 4) in lowland to montane forest.

Conservation status
The species is known from four collections from four locations and is distributed throughout Bougainville and the northern part of the Solomon Islands.The EOO (excluding unsuitable habitat) can be estimated from the areas of Bougainville (9,318 km 2 ), Choiseul (3,837 km 2 ), Kolombangara (680 km 2 ) and northern Santa Isabel island (1,000 km 2 ), totalling 14,835 km 2 below the threshold for Vulnerable, and the AOO is only 16 km 2 within the Endangered criteria.Because of the very few localities and the continued forest exploitation in the Solomon Islands, we give this species a provisional conservation rating of EN B2 ab(iii, iv).

Notes
There are at least two more species of Monoon from the Solomon Archipelago but the material available to us (BSIP 15202, BSIP 13474, Craven 537) is too limited to describe.

Huberantha in the Pacific
Huberantha was only recently recognised as an independent genus; excised from the amorphous Old World Polyalthia s. lat.After a false start with the name Hubera (Chaowasku et al. 2012), some 27 species ranging from East Africa and Madagascar to the South Pacific were transferred to Huberantha (Chaowasku et al. 2015), to be followed by one more from India (Muralidharan et al. 2015) and 4 from Vietnam, the Philippines and New Guinea (Turner 2016).However, the taxonomy of genus is poorly known, particularly in New Guinea and the Pacific.Herbarium material from the Pacific islands included at least 2 new species of Huberantha, which are described below.
We consider these species to belong in Huberantha because they have uniovulate carpels, brochidodromous venation with non-decurrent insertion of lateral nerves to the midrib and more or less cuneate, rather than subcordate leaf bases, and relatively hard seeds.

Diagnosis
There are three species of Huberantha in Papuasia and the Pacific that exhibit similar tomentose twigs to the material from the Solomons.The poorly known Huberantha hirta (Miq.)Chaowasku and Huberantha trichoneura (Diels) Chaowasku from New Guinea differ in leaf shape (Huberantha hirta: symmetrical, oblong-ovate; Huberantha trichoneura: symmetrical, oblanceolate with an acute base vs asymmetrical, typically lanceolate with base rounded to obtuse in Huberantha asymmetrica sp.nov.) and in having more or less globose fruits vs conical to ellipsoidal in Huberantha asymmetrica sp.nov.Huberantha loriformis (Gillespie) Chaowasku from Fiji, is distinctly hairier than Huberantha asymmetrica sp.nov.with dense tomentum on the lower lamina and often hairs on the upper lamina giving a soft furry feel below and a scabrid one above.The hairs on the flower pedicels and calyx are longer and denser, and the petals are more distinctly lanceolate with long acute apex in Huberantha loriformis compared to Huberantha asymmetrica sp.nov.The stipes of the monocarps in Huberantha loriformis are shorter (3-5 mm vs 5-15 mm) but thicker (2 mm vs 1 mm).

Etymology
The chosen epithet reflects the asymmetical leaves.

Description
Tree to 12 m tall, 30 cm dbh.Twigs variably tomentose, from densely and persistently red-brown or pale brown hairy, at least on youngest parts, to sparsely so; otherwise drying brown, longitudinally striate, often with impressed lozenges.Leaves chartaceous, drying brown or grey-brown generally with midrib below appearing a darker brown, midrib flush to slightly sunken above, prominent below, lateral nerves flush to very slightly raised above, raised below; hairs, sometimes dense, on nerves and midrib below and along midrib above, sometimes scattered on lower lamina surface; lamina oblong-ovate or oblongobovate to more typically elliptic-lanceolate to lanceolate, 3.5-19 × 1.7-7 cm, usually asymmetric with one half slightly larger, most obvious as a lopsided base to the leaf, apex acute to more frequently acuminate, base obtuse to rounded, lateral nerves 8-14 pairs, looping distinctly well within margin, tertiary venation reticulate, distinct on both surfaces in dry leaves; petioles 3-5 mm long, 0.5-2 mm thick, sparsely to densely hairy.Inflorescences axillary, peduncle ca 1 mm long, densely red-brown hairy, apparently bearing a single flower at a time.Flowering pedicel 22-24 mm long, ca 1 mm wide, broadening distally slightly, drying dark brown or black, longitudinally striate, minutely pimpled with sparse red-brown hairs; sepals ovate-lanceolate ca 5 × 3 mm, drying dark brown or black with scattered red-brown hairs externally, glabrous within, calyx lobes distinctly separated, not touching even at base; petals linear-lanceolate, ca 3 cm long, drying black or dark brown with scattered pale hairs, inner petals slightly wider (9 vs 7 mm); stamens many, ca 1 mm long, drying pale brown, connective apex truncate, very minutely hairy or papillose; carpels many, ca 1 mm long, densely pale hairy, stigmas ca 1 mm long.Fruiting pedicel 1.5-4 cm long, 1-2 mm diameter, drying dark brown, striate, with scattered hairs, monocarps few to at least 20, rather variable in shape from conical to ellipsoidal but generally broadest near base and tapering to an acute apex, 15-18 × 5-10 mm, drying black with a few coarse wrinkles and pimples and scattered red-brown hairs, stipe 5-15 mm long, ca 1 mm wide, drying longitudinally striate with a scattering of red-brown hairs.Seeds 1.

Distribution and habitat
Solomon Islands (Fig. 6) in lowland and hill forest, to 600 m a.s.l.

Conservation status
This new species is endemic to the Solomon Islands but is known only from 10 collections from 10 locations, with the last collection made in 1968.The EOO (excluding unsuitable habitat) is 15,600 km 2 falls within the Vulnerable criterion, and the AOO of 40 km 2 is within the Endangered criterion.Because of the number of collections (10 or less) and the amount of excessive logging in the Solomon Islands (Katovai et al. 2015), we give Huberantha asymmetrica sp.nov. a preliminary conservation assessment of VU B1ab(iii, iv).

Diagnosis
Similar to Huberantha amoena of Fiji but with broader leaves in absolute (4-6.5 cm vs up to 4 cm) and relative terms (length: breadth ratio of less than 3 vs 3-4), less slender flowering pedicel (0.75 vs 0.5 mm diameter), broader stamen connective apex (1.5 vs 0.5 mm), and longer stipes to the monocarps (12-15 vs 10-11 mm).Huberantha amoena appears habitually to have tiny hairy domatia in the axils of the lateral nerves on the abaxial lamina surface which are absent in the material of Huberantha whistleri sp.nov.

Eponymy
We are pleased to name this species in honour of W. Arthur ("Art") Whistler, the discoverer of this and many other Pacific taxa.

Description
Tree 8 m tall.Twigs drying dark brown or grey-brown, longitudinally striate or with impressed lozenges, glabrous.Leaves membranous to chartaceous, glabrous, drying grey above with midrib pale brown, paler grey below with midrib dark brown, midrib slightly sunken above in dry leaves, prominent below, lateral nerves slightly raised on both surfaces, lamina oblong-ovate to oblong-lanceolate, 11-18 × 4-6.5 cm, apex acuminate, base obtuse to rounded, ultimately slightly decurrent to petiole, lateral nerves 9-12 pairs, initially running out at about 70˚ to the midrib then arching forward and looping some 1-4 mm within margin, tertiary venation reticulate and visible from both surfaces in dry leaves; petiole drying blackish or dark brown, 6-9 mm long, 1-

Distribution and habitat
Samoa (Fig. 8) in hill forest.

Conservation status
The species is currently only known from the northern slopes of Savai'i (we have not had access to the second sterile collection Whistler 9481a -above Sāsina in lowland forest at 270 m a.s.l.).Whistler (2011: 75) has noted that the species is "rare in lowland to foothill forest" in this location, but he gives no further information on the habitat or the population size.From Google Earth imagery, the habitat is disturbed in some areas on the north coast around Sasina (but this may be natural disturbance due to typhoons), but also shows some areas with complete tree cover, and with only two points we are unable to calculate an EOO; we therefore we give this species a preliminary conservation rating of Near Threatened (NT).

A list of the Annonaceae species of the Western Pacific
Species are listed alphabetically within genera.Synonymy and typification are included.The regional distribution (in the Western Pacific) of each taxon is given.For genera, this is summarised as a distribution map.For species, a listing by island or island group is made citing representative collections, if a relevant type specimen is not already cited.

Notes
In their paper confirming the phylogenetic separation of Drepananthus from Cyathocalyx, Surveswaran et al. (2010) considered Cyathocalyx novoguineensis as a synonym of Drepananthus petiolatus (Diels) Survesw.& R.M.K.Saunders.In our opinion these two taxa can be distinguished.The petal blades are generally much shorter in Drepananthus petiolatus (to 1 cm long compared to at least 6 cm in Cyathocalyx novoguineensis from New Guinea), more strictly linear rather than long tapering, and glabrescent vs densely pale hairy.Drepananthus petiolatus appears to be a highland species and Cyathocalyx novoguineensis a lowland one, though there may be some overlap in altitudinal ranges.However, there is no indication that the different morphologies are simply an effect of altitude.We therefore make a new combination here for Cyathocalyx novoguineensis in Drepananthus.
There is a species of Drepananthus widely collected in the Melanesian Solomon Islands.Morphologically the specimens are similar to Drepananthus novoguineensis (Baker f.) I.M.Turner & Utteridge comb.nov.The specimens seen have shorter petal blades than the New Guinea material (to 2 cm long vs up to 6 cm) and they are less densely hairy, but otherwise flower and fruit forms are congruous.We therefore include this Solomon Islands' material in Drepananthus novoguineensis (Baker f.) I.M.    (Smith 1943).-Type: Fiji, Viti Levu, Naitasiri Province, Tamavua woods, 7 miles from Suva, 9 Aug. 1927, J.W. Gillespie 2198 (holo-: A00039617; iso-: GH00039618).

Regional distribution
Fiji.

Regional distribution
Palau.

Notes
Kanehira cited two specimens in the protologue of this species; his numbers 477 and 531, both collected in Palau.Images of the specimens in the Herbarium of Kyushu University (FU) show that either the original field labels or the Flora of the Caroline Islands labels have got transposed between the sheets (477 on the field label is mounted with 531 on the FCI label and vice versa).In the lectotype designation above it is the number on the field label that is followed.An annotation of 477 in red indelible pencil on the paper wrapping the material in the packet on the lectotype sheet seems to indicate that it is the Flora of the Caroline Islands labels that are in error.This means that the specimen in US with 477 on a FCI label is probably not an isolectotype.(Smith 1936).

Regional distribution
Fiji.

Regional distribution
New Caledonia.

Regional distribution
Fiji.

Notes
Some fruiting specimens from the island of Vanikoro in the Santa Cruz group, and one from Pentecost Island in Vanuatu, appear similar to Huberantha capillata, a poorly known species from Fiji.They are referred to the species with some doubt.

Regional distribution
Fiji.

Regional distribution
Fiji.
See page 12 of this article for description and distribution.

Notes
There is a second Huberantha species from the main islands of the Solomons.It has glabrous twigs and unbeaked ellipsoidal monocarps which distinguish it from Huberantha asymmetrica sp.nov.However, in the absence of flowers it is difficult to be certain that it is not one of the species from New Guinea.1912).-Type: Oncodostigma leptoneurum Diels.

Regional distribution
Tonga.

Regional distribution
Fiji.

Regional distribution
Fiji.

Notes
The only part of the holotype in BISH that could not be traced recently was a wood specimen (B.Kennedy, pers. com.).

Regional distribution
Fiji.

Regional distribution
New Caledonia.

Notes
Baillon described Melodorum punctulatum from New Caledonia.The reference to Pancher in the opening sentence of the protologue is the only clue to the type of the name.Guillaumin (1932) reported that Baillon's type was lost; as did van Heusden (1996) who treated the name as dubious.She stated that Baillon's description did not "fit exactly any of the "varieties" of Meiogyne tiebaghiense".As an exact fit is not required, rather a lack of serious conflict between the description and the type, we feel Baillon's name cannot simply be ignored and make a new combination for it in Meiogyne.We follow the suggestion of Guillaumin (1932) that Balansa 1174 can be considered representative of Baillon's species and designate the duplicate in the Paris Herbarium with Balansa's original label as neotype.(Rauschert 1982).

Notes
The presence of Popowia in the Solomon Islands can be confirmed from the herbarium material available.These specimens have previously been assigned to Popowia pisocarpa.Moeljono (2012) did not record Popowia pisocarpa from mainland New Guinea or from the Pacific Islands, so the identity of the plant from the Solomons remains doubtful.

Notes
The Uvaria material from the Solomons has generally been referred to Uvaria rosenbergiana Scheff., a species described from New Guinea.The correct name for the Solomon plant will only become clear after revision of the genus in the Asia-Pacific Region.Pseudannona Saff., Journal of the Washington Academy of Sciences 3: 17 (Safford 1913).-Type: Pseudannona amplexicaulis (Lam.)Saff.

Regional distribution
Fiji.

Notes
The only part of the holotype in BISH that could not be traced recently was a wood specimen (B.Kennedy, pers.com.).

Discussion
Of the nine genera in the south-west Pacific, four (Monoon, Polyalthia s. str., Popowia and Uvaria) have not been recorded beyond the Solomons.Drepananthus, Goniothalamus and Xylopia all occur in Fiji, with the latter two also in New Caledonia.Meiogyne, reaching Tonga, and Huberantha, making it to Samoa, are the two genera with the most extensive ranges.Surprisingly, Meiogyne has not been recorded from the Solomons.However, it does occur in Guam and the Northern Marianas making it the Annonaceae genus with the most extensive range in the Pacific.Biogeographical analysis based on molecular phylogenies supports a post mid-Miocene divergence within Huberantha of an Africa-Madagascar clade from the ancestral Asian taxa (Thomas et al. 2015).This represents a dispersal direction counter to the general trand in the family of migration from Africa to Asia (Thomas et al. 2015), and for Huberantha, implies successful long-distance dispersal from Asia to Africa which is also likely to have occurred from mainland Asia to the Pacific.Huberantha species have relatively small fruits and seeds which may facilitate endozoochory, and they are represented in more markedly seasonal climates (Thomas et al. 2015), which may contribute to successful long-distance dispersal.However, it is perhaps more difficult to identify such characteristics in Meiogyne that would explain its success in colonising the Pacific, or, for instance, why Polyalthia s. str., which occurs in seasonal sites and often has small fruits, has not done so.
The Annonaceae in Australia are closely confined to the mesic strip of the north-eastern coast of the continent with a few outliers on the northern promontories (Jessup 2007) (Fig. 20).Success at colonising Australia is no absolute guarantee of success at colonising the Pacific islands.While Huberantha and Meiogyne reach New South Wales on the Australian mainland, reflecting their spread in the Pacific, Uvaria, the third Annonaceae genus to reach New South Wales, is not a great success in the Pacific, with a single species making it to the Solomon Islands.In contrast, genera such as Drepananthus, Goniothalamus and Xylopia, which have been successful in the Pacific are either absent from mainland Australia altogether or have very restricted ranges in northern Queensland.
Uvaria is the only climbing genus of Annonaceae to be found on the Pacific Islands.There is a clear decline in the proportional abundance of Annonaceae climber species compared to tree species as one moves eastwards in Malesia.For instance, while climbers make up more than 25% of the species in Borneo, they barely exceed 15% of the species in New Guinea and only a single climber species gets to the Solomons.
The common pattern of zoochorous dispersal (frugivourous birds and bats in the Pacific) and ecological dependence on forest (intolerance of open, drought-prone habitat) among members of the Annonaceae are likely to make them slow colonisers (Thomas et al. 2015;Stull et al. 2017).The rather 'hit-and-miss' geographical pattern exhibited by the various Annonaceae genera across the south-west Pacific seems to reflect random dispersal events as much as any adaptive colonising ability in these phylogenetic lines.
It may be that the poverty of climbing taxa in the Pacific is also a random effect but it could also reflect a more marked dispersal and colonisation limitation in the lianoid, compared to the arborescent, clades.

Fig. 9 .
Fig. 9. Regional distribution of the genus Drepananthus (Annonaceae) in the Pacific.Base map sourced from CartoGIS, College of Asia and the Pacific, The Australian National University, Australia.

Fig. 10 .
Fig. 10.Regional distribution of the genus Goniothalamus (Annonaceae) in the Pacific.Base map sourced from CartoGIS, College of Asia and the Pacific, The Australian National University, Australia.

Fig. 12 .
Fig. 12. Regional distribution of the genus Huberantha (Annonaceae) in the Pacific.Base map sourced from CartoGIS, College of Asia and the Pacific, The Australian National University, Australia.

Fig. 13 .
Fig. 13.Regional distribution of the genus Meiogyne (Annonaceae) in the Pacific.Base map sourced from CartoGIS, College of Asia and the Pacific, The Australian National University, Australia.

Fig. 14 .
Fig. 14.Regional distribution of the genus Monoon (Annonaceae) in the Pacific.Base map sourced from CartoGIS, College of Asia and the Pacific, The Australian National University, Australia.

Fig. 17 .
Fig. 17.Regional distribution of the genus Popowia (Annonaceae) in the Pacific.Base map sourced from CartoGIS, College of Asia and the Pacific, The Australian National University, Australia.

Fig. 18 .
Fig. 18.Regional distribution of the genus Uvaria (Annonaceae) in the Pacific.Base map sourced from CartoGIS, College of Asia and the Pacific, The Australian National University, Australia.

Fig. 19 .
Fig. 19.Regional distribution of the genus Xylopia (Annonaceae) in the Pacific.Base map sourced from CartoGIS, College of Asia and the Pacific, The Australian National University, Australia.

Fig. 20 .Sargentia 1 :
Fig. 20.Regional distribution of the Annonaceae in the Pacific.The numbers next to each island or island group represents the number of native Annonaceae species and genera found there (number of species/number of genera).The numbers for New Guinea remain approximate.The numbers for the Solomon Islands include Bougainville and the Santa Cruz Islands.Base map sourced from CartoGIS, College of Asia and the Pacific, The Australian National University, Australia.
Surveswaran et al. (2010)A.C.Sm., Journal of the Arnold Arboretum 31: 162(Smith 1950).-Type:Fiji,Viti Levu, in the valley of Nggaliwana Creek, north of the sawmill at Navai, 21 Jul.1947,A.C.Smith 5342 (holo-: A00039268; iso-: BISH, BRI, K, L, NY, P, S, US).Drepananthus collected from Vanikoro Island in the Santa Cruz group have far broader petals than the material from the Melanesian part of the Solomon Islands.Surveswaran et al. (2010)reduced the four species of Cyathocalyx described by Smith from Fiji to Drepananthus vitiensis.The limited amount of material available from Vanikoro seems to fall within the variability exhibited by the Fijian taxon, so we refer the collections to that species.