Five new species of Rhodamnia (Myrtaceae, Myrteae) from New Guinea

Abstract Five new species of Rhodamnia are proposed for New Guinea, including Rhodamnia asekiensis, Rhodamnia daymanensis, Rhodamnia makumak, Rhodamnia taratot, and Rhodamnia waigeoensis. Rhodamnia sharpeana, known previously only in Australia, is reported for the first time for Papua New Guinea. Detailed species descriptions and associated taxonomic data are provided for all species. A key is provided for species of Rhodamnia with stellate trichomes. Given the overall paucity of collections, all species are tentatively assigned as Data Deficient following IUCN conservation recommendations.


Introduction
Rhodamnia Jack is recognized easily among the baccate genera of Myrtaceae in Malesia and Melanesia by its 4-merous fl owers (apart from a 5-merous species in New Caledonia), uniloclular ovaries, parietal placentation, and sclerotic seed coats (Scott 1979;. Based on the author's current taxonomic perpectives and including those newly proposed here, Rhodamnia includes 42 species. Th e genus occurs from Myanmar, Th ailand and China through Malesia and Australia, and east through Melanesia to the Solomon Islands (Scott 1979;Kress et al. 2003). Th e Australian species recently were treated ) and another new species was described from New Guinea (Snow and Takeuchi 2009). However, Rhodamnia remains imperfectly known in New Guinea because of low collecting densities from that island, and because some species are known from only one or a few collections.
Th e fi ve species newly proposed here were recognized during curatorial duties associated with fl oristic inventories in Papua New Guinea by Bishop Museum. Th e purpose of this paper is to describe the new species of Rhodamnia, summarize their diagnostic character traits, and to provide a distribution map and conservation threat assessments. It also discusses the fi rst New Guinean occurrences of Rhodamnia sharpeana, previously known only from Australia .

Materials and methods
Measurements are based primarily on dried herbarium specimens, although dimensions for fl owers and fruits were supplemented by rehydrating material in boiling water. Terminology follows that used in recent treatments for the genus Snow and Takeuchi 2009), the Systematics Association (1962) for two-dimensional shapes, and Th iers (2012) for acronyms. An exception is the present use of the term colleters in lieu of stipules in light of recent studies (da Silva et al. 2012). Descriptions for color are standardized where possible to Beentje (2010) or reported in accordance with data provided on specimen labels. As used here, the leaf apex refers to the distal 25% of the laminar surface, whereas the tip refers to the distal 10% . Conservation threat assessments follow IUCN (2010). Takeuchi (2000) discussed the inconsistency of vernacular names in Papua New Guinea and provided an example from Myristicaceae in which a common name was applied widely across most of the family. "However, the vernacular name is reported here if it was indicated on the specimen label.

Data resources
Th e data underpinning the new species described in this paper are deposited at GBIF, the Global Biodiversity Information Facility, http://ipt.pensoft.net/ipt/resource. do?r=snow_1_rhodamnia_new_guinea.  Description. Trees of unknown height; crown dense. Bark of main bole light grey, vertically fi ssured. Indumentum (branchlets, fl owers, fruit) short-sericeous, sparsely to moderately dense, color more or less saff ron (Beentje 2010). Branchlets terete, wingless, dark brown (dried); epidermis smooth, oil glands absent. Leaves opposite, evenly distributed along branchlets, strongly discolorous; venation perfect basal or slightly suprabasal acrodromous, secondary and tertiary veins visible above and below, the more prominent secondaries ca. 20-25 per side abaxially, the secondaries near base of blade splitting as they approach lateral primary vein and contrasting with those towards apex of blade that are mostly unbranched; intramarginal vein less pronounced than secondaries, parallel to leaf margins, 0.8-1.1 mm from margin at midpoint of blade. Colleters absent. Petioles 11-13 mm long, round to slightly sulcate above. Leaf blades 10.5-16.0 cm long, 3.5-4.5 cm wide, narrowly ovate (to elliptic), base cuneate, apex acuminate, tip acute; adaxial surface matte, glabrescent at base, midvein slightly and narrowly raised proximally but becoming fl ush distally; abaxial surface densely short and strongly-appressed sericeous between the secondary and tertiary veins, midvein projecting throughout, oil glands not visible. Infl orescence terminal or lateral, fl owers solitary (=monads) or in 3-fl owered cymes ("botryoids" of some authors), pedicels of monads up to 10 mm long. Bracteoles not seen, apparently caducous in fruit. Flowers unknown. Hypanthium (based on fruit) evidently not ribbed, hairy. Calyx lobes (in mature fruit) 2.5-3.0 mm long, more or less glabrous adaxially, moderately sericeous abaxially, persisent and erect in fruit. Ovary (from mature fruit) and locule 1, placentas 2, linear; ovules disposed in regular rows. Berries subcylindrical, somewhat pyriform or tapering at the base, 8.5-14.0 mm long, 8-11 mm wide, sparsely sericeous, dull dark red (fresh) or blackish (dried). Seeds 4-10 per fruit, 4.5-5.2 mm long, 2.8-5.0 mm wide, rounded on outer portion adjacent to fruit wall but highly angular and irregularly elsewhere, light brown, seed coat highly sclerotized. Embryos not seen.

Rhodamnia asekiensis
Phenology. Flowering unknown; fruiting confi rmed only for May. Distribution. Known only from Morobe Province, Papua New Guinea, on the side of a ridge in a secondary forest; ca. 1465 m.
Conservation status. Data Defi cient; but the subsequent lack of collections of this species over the past 45 years locally and regionally suggest that Th reatened might more accurately refl ect is true status.
Phenology. Flowering in June; fruiting interval unknown. Distribution. Papua New Guinea, Milne Bay Province, north slopes of Mt. Dayman in the Maneau Range; mossy forest of ridge crests over metamorphic rocks (see Davies 1980;Daczko et al. 2009) at ca. 2250 meters.
Conservation status. Data Defi cient. Th e collection label indicates the species was common (at least locally) at the time of its collection in 1953. However, the absence of additional collections over the past sixty years suggests that Th reatened might more accurately refl ect its true status.
Comments. Rhodamnia daymanensis appears to be part of the "pearly" group ) by virtue of its abaxial indumentum. Scott (1979) Among the species of Rhodamnia in New Guinea occurring at elevations above 2000 meters with a similar abaxial indumentum, R. daymanensis mostly closely resembles R. lancifolia. Th e type collection of R. lancifolia (2425 m) is approximately 25 km west of the type locality of R. daymanensis (2250 m) in similar habitats. However, R. lancifolia diff ers by its more narrowly elliptic leaves, a less pronounced petiolar sulcus, slightly impressed adaxial laminar midvein (vs. more deeply impressed in R. daymanensis in the proximal half), and the more yellowish (and longer, on average) abaxial laminar indumentum. Th e adaxial leaf surface of R. lancifolia, for which there are many collections, is nearly black when dried, which contrasts with the fucosus (dark greyish brown, Beentje 2010) dried color of R. daymanensis. Th e fl owers (presumably hypanthium and abaxial surfaces of calyx lobes and petals) of R. lancifolia have a brownishpinkish indumentum (Stevens & Veldkamp LAE 55582; isotype [L!]), whereas the fl oral indumentum of R. daymanensis is mostly distinctly yellowish.  Description. Trees to 25 m. Buttresses present but low of stature; fl uting or twisting absent. Bark of main trunk reticulate-fl aky, brownish. Indumentum, where present (branchlets, petioles, abaxial leaf surface, distal portion of adaxial leaf mid-vein, peduncles, bracteoles, hypanthium, calyx lobes, adaxial petal surfaces), densely tomentose and velvety in texture, consisting of stellate, ferrugineous trichomes. Branchlets terete to compressed. Leaves opposite, more or less evenly distributed along branchlets, discolorous; venation perfect or imperfect suprabasal acrodromous, secondary and tertiary veins faint but visible adaxially, intramarginal vein faintly visible from adaxially, tracing irregularly between tips of secondary veins and ca 0.5 mm from blade margin. Colleters absent. Petioles 4.5-6.5 mm long, rounded in transverse section. Leaf blades 4.5-7.5 cm long, 1.4-2.2 cm wide, narrowly elliptic, base cuneate, margin fl at, apex acuminate and sometimes falcate, tip (uppermost 10% of blade) acute; adaxial surface matte, midvein slightly sulcate more or less throughout to sometimes fl ush distally, tomentose proximally; abaxial surface orangish-velvety by virtue of indumentum, midvein projecting throughout. Infl orescence terminal and lateral, solitary or paired to mostly a fasciculate cluster of monads, the monads sessile or on pedicels up to 3 mm long. Bracteoles 1.8-2.3 mm long, 0.4-0.6 mm wide, linear, rigid, ascending to erect, the apex not reaching base of calyx lobes, persisting. Hypanthium campanulate; anthopodium (if present) up to 1 mm long; metaxyphylls absent. Calyx lobes 4, 2.2-2.7 mm long, 2 (of the 4 lobes) more or less rectangular (length-width ratio 3:2), slightly longer than the 2 shorter, broadly ovate (3:2) lobes; adaxial surface densely tomentose or somewhat less so basally and near margins, abaxial surface densely tomentose throughout. Petals (material sparse) 2-2.5 mm long, 2-2.3 mm wide, elliptic to ovate, tomentose above and below. Stamens ca. 30-40, fi laments 2-3 mm long; anther sacs ca. 0.5 mm long, globose, sub-basifi xed. Style 3.5-4 mm long, hairy below; stigma narrow to slightly capitate. Fruit not seen.

Rhodamnia makumak
Phenology. Flowering confi rmed only for early July but likely also in late June; fruiting unknown but probably June to July and possibly longer.
Distribution. Papua New Guinea, Milne Bay Province; known only from rainforest on a plateau of ca. 350 meters elevation.
Conservation status. Data Defi cient. Etymology. From the local vernacular name "makumak" as a noun in the nominative. Vernacular name. Makumak in the local Daga language. Comments. Rhodamnia makumak is part of a group of species characterized by a hypothesized synapomorphy of stellate trichomes . Scott (1979) treated the type collection as R. blairiana var. blairiana, which as presently understood occurs only in Australia . Dr. Gordon Guymer (BRI), who worked previously on Rhodamnia, likewise recognized the affi nity of the type collection to R. blairiana, judging from his specimen annotations.
Rhodamnia makumak is said to be a large tree with low buttresses (dimensions of buttresses lacking on label). Th e best diagnostic characters include the stellate, ferrugineous indumentum on leaves and hypanthium, which imparts a densely velvety appearance; the sessile to subsessile axillary clusters of fl owers; and narrowly elliptic leaves bearing an acuminate and sometimes falcate apex. A provisional key to species with stellate trichomes follows. Description. Trees to ca. 5.5 m. Bark of main bole unknown. Indumentum (branchlets, leaves, fl owers, fruit) mostly densely tomentose-lanate, the trichomes highly crisped, ferrugineous, and generally somewhat appressed (see also description of abaxial leaf surface below). Branchlets terete to slightly compressed, reddish-brown (dried); epidermis smooth but fi nely and evenly striate throughout becoming somewhat fi ssured with age; oil glands sparse to common (obscured by indumentum on younger branchlets). Leaves opposite, evenly distributed along branchlets, somewhat discolorous; venation perfect basal to slightly suprabasal perfect or imperfect acrodromous, secondary and higher order veins abaxially prominent, the secondaries varying greatly in prominence (and thus hard to estimate numerically) but mostly spaced (2-)3-7 mm along the midvein; intramarginal vein less pronounced than the secondary veins, paralleling leaf margin closely, mostly ca. 0.5-1.0 mm from margin at midpoint of blade. Colleters absent. Petioles 9.0-13.5 mm long, terete, densely lanatetomentose. Leaf blades 6.5-12.0 cm long, 3.1-5.2 cm wide, elliptic to ovate, base cuneate to nearly rounded, apex acute to acuminate, tip acute to acuminate; adaxial surface matte, initially lanate but becoming glabrescent, midvein slightly impressed throughout; abaxial surface lanate along midvein and secondary veins when younger, increasingly glabrous with age, densely/minutely hoary between veins, midvein raised prominently throughout. Infl orescence lateral in current season's growth, fl owers solitary to mostly densely fascicled, sessile to subsessile with pedicels up to 5 mm long, the pedicels lax, sometimes bending. Bracteoles ca. 2.0-2.5 mm long, ca. 0.5 mm wide at base, linear, persisting in fl ower and frequently in fruit. Hypanthium cupulate. Calyx lobes 2.5-3.5 mm long, ovate, apex obtuse, densely hairy abaxially but adaxially less so (especially proximally) with age, persisent and erect in fruit. Petals (material scanty), ca. 4.0-4.5 mm long, up to 3.5 mm wide, broadly obovate, more or less glabrous adaxially, densely lanate abaxially. Staminal disk ca. 4.5 mm in diameter; staminal ring narrow, shortly villous-lanate (trichomes whitish-yellow). Stamens numerous (estimated 75-105); anthers sacs (material scanty) cylindrical, ca. 1.0 mm long, bearing a single apical gland; fi lament length unknown. Styles not seen, but persisting bases densely lanate in fruit. Ovary with 1 locule; placentas 2; placentation parietal; ovules numerous. Fruit subglobose, 7.5-8.5 mm long (probably immature) x 8.0-9.5 mm wide, greenish when young but becoming brownish on account of dense indumentum. Seeds somewhat compressed, ca. 1-2 mm thick.
Conservation status. Data Defi cient; possibly Th reatened for same reasons cited above for R. asekiensis.
Etymology. Th e specifi c epithet is derived from toratot as a noun in the nominative. Vernancular name. Locally known as toratot in the Nowata language.
Conservation status. Data Defi cient given the lack of recent information or collections. Rhodamnia waigeoensis is presently known only from two collections. Th e specimen on the type label indicates that the species was common locally at the time of its collection nearly sixty years ago. A vegetation type similar to that of the type gathering occurs on the island of Rauki, where the species also may occur. While the reported ethnobotanical use of R. waigeoensis for cigarette making may lend the species some protection, it also may have encouraged overexploitation.
Vernacular name. Kikir (in the Malayan language). Ethnobotany. Th e herbarium label indicates that the leaves are used for making cigarettes.
Comments. Rhodamnia waigeoensis belongs in the "pearly"group of species given its nacreous indumentum . Scott (1979) included the type gathering of R. waigeoensis in R. novoguineensis A.J. Scott and the paratype gathering in R. pachyloba A.J. Scott.
Waigeo Island is part of the Raja Ampat Islands of Indonesian New Guinea. Th e region harbors unusual vegetation assemblages ( van Royen 1960), has high rates of endemism (Supriatna 1999), and was the subject of relatively recent rapid-assessment surveys (Takeuchi 2003a). Van Royen (1960: 54-56) summarized the vegetation on portions of Waigeo Island using six broad categories. One of these, xerophytic vegetation, is described as having three variants, one being dominated by Myrtaceae.
Th e label of the type specimen refers directly to the xerophytic vegetation located behind the small village of Waifoi on the east bank of Majalibit Bay. Takeuchi (2003a,b) reported that the Waigeo ultrabasic vegetation resembles the pioneer communities on the ultrabasics at the Kamilai Wildlife Management Area (KWMA) in the Bowutu Mountains (Morobe Province, Papua New Gueina). Communities at KWMA can be topographically unstable due to landslides, but in general appearance and composition are similar to those on Waigeo. However,  believes the vegetation on the Waigeo ultrabasics is primarily caused by fi re succession.

Discussion
Sixteen new species of Rhodamnia, including the fi ve newly proposed here, have been described since Scott's (1979) generic revision (Guymer and Jessup 1986;Guymer 1998;Snow and Guymer 1999;Snow et al. 2001;Snow and Takeuchi 2009). Apart from the new species and those that Scott (1979 and see above) treated in other taxa, the species of Rhodamnia that I recognize for New Guinea diff er from Scott (1979) in only two ways. First, I follow White (1951) and recognize R. propinqua as distinct from the Australian R. blairiana. Second, I maintained the Australian species R. spongiosa (F.M. Bailey) Domin as distinct from the New Guinea species R. glauca Blume .
Additional studies still are clearly needed in Rhodamnia. Th e phylogeny of the genus has never been established, and the hypothesized informal groups of Rhodamnia ) need testing. All new collections from New Guinea and Malesia deserve close scrutiny. Scott (1979) adopted a broad taxonomic concept of R. cinerea Jack and probably was correct to synonymize many names therein given its wide geographical distribution. However, I have seen newer collections from Malesia that may merit taxonomic recognition, so a thorough review of the Malesian species, including R. cinerea, is now warranted given the many recent collections across that region.
Eff orts also should be made to recollect all species of Rhodamnia in New Guinea given the paucity of specimens for many species and the present inability to assign conservation threat assessments with high levels of confi dence. Two suggestions for collecting in remote, biodiverse areas are worthy of repeating. First, as Takeuchi (2000) expressed for New Guinea generally, survey botanists should collect uncritically while doing inventories, since taxonomic novelties and range extensions often are discovered only many years later in the herbarium by taxonomic specialists (Bebber et al. 2010;Snow et al. 2012), and because specimens that appear to be known species may in fact be taxonomic or geographical novelties. Second, workers are encouraged to include observations of local relative abundance for each specimen, given the value that such information can provide for later conservation threat assessments (Snow 2011: 687-688), however tentative they may be.