Elaeocarpus firdausii (Elaeocarpaceae), a new species from tropical mountain forests of Sulawesi

Abstract Based on ongoing ecological research in mountain forests of Sulawesi, a new species, Elaeocarpus firdausii Brambach, Coode, Biagioni & Culmsee, sp. nov. is described and illustrated from mossy forests at > 2000 m and information provided on the species’ distribution, ecology and pollen morphology. Elaeocarpus firdausii is similar to Elaeocarpus luteolignum Coode but differs from the latter in having glabrous terminal buds, leaves with black gland dots, 4-merous, larger flowers, and more numerous stamens.


Introduction
Elaeocarpus is the largest genus of the Elaeocarpaceae, comprising approximately 350 species in the Old World tropics and subtropics (excluding mainland Africa), from Madagascar and Mauritius in the west, to Japan in the north, Australia and New Zealand in the south and Polynesia including Hawai'i in the east (Coode 2004, Baba 2013. Th e greatest number of species is found in the Malesian region and taxonomic work on these is currently under way.

Morphological observations
Th e relevant published identifi cation keys for Elaeocarpus (Coode and Weibel 1994, Coode 1995, 1996a, 1996c, 2001a, 2001b have been consulted, as well as herbarium collections of B, BO, GOET, K and L (herbarium acronyms follow Th iers (continuously updated): http://sweetgum.nybg.org/science/ih/) and online databases of digitized herbarium specimens (JSTOR 2015, RBG Kew 2015, Wieringa 2015. We also recorded the character states of our specimens in a DELTA matrix (Dallwitz et al. 2010) for Elaeocarpus in Malesia developed and maintained by MC. Most specimens of Elaeocarpus from the Malesian region in K and L have been seen by MC during his work on the genus over the last decades, so relatively few specimens remain unnamed. Our description is based solely on the material gathered during our (FB and HC) fi eldwork in Central Sulawesi in 2011-2012, as no further matching specimens were found in herbaria. All our specimens were collected from permanently tagged trees in inventory plots. Duplicates of relevant specimens, including the type, were deposited in the Indonesian herbaria BO and CEB. All specimens seen by us for the description of the new species are marked with an exclamation mark in the present paper.
For the description, we boiled up fl owers in dilute detergent for 5 minutes and dissected them afterwards. Dimensions were measured using a ruler with 0.5 mm accuracy. All colours and measures given refer to dried and pressed material unless stated otherwise. Photographs were taken in the fi eld using a Canon EOS 500D camera with a Tamron AF 18-200mm f/6.2-38 lens.
Wood density (oven-dry mass per fresh volume) was determined from three wood cores extracted with increment borers and belonging to the specimens Brambach et al. 0721, 0973, and 2041, respectively. Th e samples' fresh volume was measured by Archimedes' principle and weight was noted from the same samples after oven-drying for 48h at 105°C.

Pollen morphology
One closed fl ower bud (from the specimen Brambach et al. 2041) was processed for the description of the pollen morphology. Th e pollen grains were treated following standard Erdtman's acetolysis method (Erdtman 1960, Faegri et al. 1989. Th e samples were mounted on permanent slides with Kaiser's glycerol gelatine and the slides were analysed under a Nikon Eclipse H550L photomicroscope at a magnifi cation of 100×. Descriptions of the pollen grains were compiled following the terminology defi ned by Punt et al. (2007). Th e shape was described based on the measurements of the ratio between polar axis (P) and equatorial diameter (E) in equatorial view. Size values are based on a total of 10 grains measured, mean are shown with minima and maxima in parentheses.

Conservation Assessment
With only three known collection localities (see "Distribution"), a meaningful calculation of the extent of occurrence (EOO) and area of occupancy (AOO) (IUCN Standards and Petitions Subcommittee 2014) as basis for the conservation assessment is not feasible. We, therefore, attempted to estimate the extent and location of potential habitats for the proposed species based on its known habitat preferences. For that, we used the CGIAR digital elevation model (Jarvis et al. 2008) in QGIS (QGIS Development Team 2015) to quantify land areas in Sulawesi above the elevation threshold of 2000 m. We defi ned this threshold based on our fi eld observation of a marked and easily observable transition from mid-montane to upper montane (mossy) forest around this elevation. Th e proposed new species has so far only been recorded in upper montane forest at > 2000 m elevation (see "Habitat" below). We then assessed the forest condition at elevations ≥ 2000m using data from Cannon et al. (2007) and only used areas classifi ed as "good" or "old-growth" by them for further analysis. As the proposed species has so far been recorded in the CSM and possibly the Eastern peninsula of Sulawesi, we also excluded all upper montane areas from the Northern and Southeastern peninsulas and the tip of the Southern peninsula ( Fig. 1). Th e resulting potential habitats were used for the calculation of the extent of occurrence (EOO) and area of occupancy (AOO, grid cell size of 2 × 2 km) following the recommendations of IUCN Standards and Petitions Subcommittee (2014). Diagnosis. Similar to Elaeocarpus luteolignum Coode, but diff ering from that species in glabrous (vs minutely adpressed-hairy) terminal buds and young twigs, leaf blades with black gland dots (vs leaf blades without dots), 5-merous (vs 4-merous) fl owers, larger fl owers (e.g. sepals 5-8 × 1.5-2.5 vs 3-4 × 1.5 mm) and more numerous stamens (29-31 vs 20 Description. Trees 8-25 m tall, dbh ≤ 40 cm, without buttresses or stilt roots, fl owering when full-grown. Outer bark reddish brown, verrucose; inner bark pinkish with white streaks, granular, innermost layer yellow, easily detachable from wood, wood cream to white. Twigs glabrous, strongly angulate at fi rst, later terete, twig bark longitudinally cracking, forming a net-like pattern, with large conspicuous leaf scars and many prominent lenticels, gummy-resinous where cut, 2.5-4.0 mm thick towards the tip, with gummy-resinous, glabrous terminal buds. Stipules caducous, linear-subulate to narrow-triangular, glabrous, often gummy, 1.5-5.0 mm long, tapering, entire.

Elaeocarpus fi rdausii
Leaves spirally arranged, loosely to ± tightly grouped towards twig tips in older trees, in juveniles often scattered, appearing in fl ushes, leaves of one fl ush ± equal in size. Fresh leaves brownish-red when young, later dark green with contrasting paler midrib above, much lighter green and with contrasting darker green venation and the sometimes red midrib beneath, dying red. Petioles 2-14 mm long, 1-3 mm thick, glabrous or almost so, sometimes verrucose when mature, often longitudinally fi nely striate, usually fl at in apical third above, sometimes rounded or slightly channelled above, distinct from or merging into decurrent leaf base (variable within a specimen), pulvinous or not on both ends, without pegs at apex, sometimes with elongate glands at the junction of petiole and lamina-margin, geniculate. Blades chartaceous to coriaceous, mostly oblong-obovate, some oblong-elliptic or obovate, 2.1-4.0 times as long as wide, (5-) 6-13 (-15.5) × 1.5-5.0 (-6.5) cm, acute to obtuse (80-110°) to rounded at apex, the very tip notched and with a (sometimes fused) pair of black glands, cuneate at base or tapering towards a broadly cuneate base (the larger leaves more narrowly cuneate), occasionally rounded, surface sometimes bullate, dull and glabrous above, glabrous or sometimes with some short adpressed hairs on the midrib beneath when young and then soon glabrescent, glabrous and not verrucose beneath when mature, with minute black gland dots on both sides. Midrib darker than lamina, prominent but widened and fl attened towards base above, strongly prominent beneath, with 8-16 pairs of main lateral veins, diverging at 60-80° from midrib, straight for most of their length or curved, breaking up 3/4 to 7/8 inside margin, looping forward and mostly joining up; usually with intermediate veins in between, ± prominent and of same colour as or paler than lamina above and below, higher-order veins reticulate, obscure or ± clear and raised above and below, of same colour as lamina, areoles squarish, < 2 mm across, domatia absent. Margins ± entire to weakly glandular-serrate, sometimes less serrated in lower half, the teeth 2-11 mm apart, glands present regardless of serration, 0.5 mm long, spindle-or claw-shaped, sometimes elongate along margin, black.
Flowers bisexual, 5-merous (once 6-petalled), spiral or almost whorled on infl orescence, bracts early caducous, not seen, pedicels 6-18 mm long and 0.5-1 mm thick in fl ower, bent downwards and thickened at apex, buds ovoid, acute at apex. Sepals 5-8 × 1.5-2.5 mm, cream-coloured when fresh, not verrucose and ± pale adpressed-sericeous outside, densely white-velutinous next to the margins inside, otherwise short-sericeous inside but glabrous in the basalmost 1.5 mm, keeled inside for whole length. Petals thick and opaque, ivory-coloured on account of the hairs when fresh, oblong, parallelsided almost to base, rounded to a narrow (1 mm wide) base, 6.5-7.5 mm long, 2.0- Figure 2. Elaeocarpus fi rdausii. a branch with leaves and fl owers (note red leaf-galls) b bark slash c branch apex with infl orescence d underside of mature leaf e fl owers with golden disc and grey anthers f reddishbrown young leaves g green young leaves h conspicuous reticulation on underside of mature leaf i clustered arrangement of leaves; j young twig with stipules k fl owers on apically bent pedicels. a, c, e, g, i, and k from the type collection (Brambach et al. 1953); b, d, f, h, and j from Brambach et al. 2041. 2.5 mm wide at widest point of limb, rounded at apex and divided into 9-12 narrowtriangular apical divisions 0.3-1.0 mm long, divisions unequal in length and grouped into lobes and acute at tip, not verrucose in dried material, densely white-sericeous outside, margins velvety or densely short-hairy throughout, densely short-hairy inside except for glabrous patch near base, with a low, narrow keel inside running for most of limb length, ± fl at at midpoint and fl at at base, without any infolding of margins. Disk golden when fresh, ± annular, 10-toothed, 0.5-0.8 mm high, densely covered with short, straight, golden hairs. Stamens 29-31, inserted in a ± single ring between disk and ovary; fi laments 0.6-1.8 mm long, straight to somewhat incurved tapering from base to apex, glabrous or with a few minute hairs; anthers 1.6-2.5 mm long, khaki when fresh, minutely hairy, with outer tooth clearly much longer than inner and with a beak 0.2-0.5 mm long, beak glabrous or with a few minute hairs without setae at tip. Ovary placed above the disk, shape clearly narrowed at base, 2.0-2.5 mm long, densely short-to medium-hairy, 2-3-locular; ovules 8-12 per locule; style 2.5-3.5 mm long, stout, tapering to a point, glabrous except for the very base.
So far, only one other case of pollen dimorphism has been documented for the genus Elaeocarpus (Huang 1972). In E. fi rdausii, the low percentage (ca. 4%) of the 2-colporate type as compared to the 3-colporate suggests the former is an aberrant morphology, possibly associated with hybridism as reported in other species (e.g. Bhowmik and Datta 2012).
Distribution. Endemic to the central part of Sulawesi. Th e species is so far recorded with certainty from Mt Rorekautimbu and Mt Malemo at elevations from 2150 to 2400m (Fig 1). Both mountains are located within LLNP. During our ecological  fi eldwork, we recorded E. fi rdausii in all three inventory plots at > 2000 m, although with rather few individuals at each site. Because of its apparent association with a distinct habitat (upper montane or mossy forest above c. 2000 m) and the general lack of information from montane habitats in Sulawesi, we consider it very likely that E. fi rdausii occurs in many of the upper montane forests of the CSM (Fig 1).
Habitat. Based on the morphological information available E. fi rdausii is a regular component of upper montane ( Etymology. Th e specifi c epithet honours our colleague Firdaus Dg. Matta (born 1984), formerly with Herbarium Celebense in Palu, Sulawesi, who collected the type specimen and contributed greatly to the success of our fi eldwork with his skills in plant collection and identifi cation.
Conservation status. Based on the locations of the estimated potential habitat for E. fi rdausii we calculated an EOO of 58 534 km² and an AOO of 5 760 km². Th e latter is presumably an overestimate as not all potentially suitable sites will necessarily be occupied by the species. Nevertheless, occurrence over a relatively wide range is plausible, given the large distance (c. 55 km) between two of the collection sites. It is thus unlikely that either EOO or AOO will fall below the thresholds of criteria B1 or B2 for IUCN category VU (IUCN 2012). While deforestation is an ongoing threat to Sulawesi's forests, upper montane forests are usually less aff ected because of their remote locations and diffi cult access (Cannon et al. 2007). Hence, we do not consider habitat destruction or exploitation by humans as an imminent threat to population levels. Given (1) the uncertainties in the estimated EOO and AOO, and (2) the recommendation to use a precautionary attitude in conservation assessments (IUCN Standards and Petitions Subcommittee 2014), we propose a preliminary extinction risk assessment of "Near Th reatened" (NT) following the IUCN Red List Categories and Criteria (IUCN 2012).
Notes. Based on the morphological information available, E. fi rdausii is probably related to E. luteolignum, E. gambutanus Coode and E. linnaei Coode; this assemblage may be sister to the Polystachyus group from Western Malesia.
In addition to the morphological diff erences between E. fi rdausii and E. luteolignum mentioned in the diagnosis above, according to our present knowledge there are diff erences in habitat preference: E. fi rdausii occurs in mossy forest at higher elevations while E. luteolignum is known from lower to mid-montane forest dominated by Fagaceae at 1200-1800 m (Coode 1995).
Both observations in the fi eld and examination of dried specimens show that there are morphological diff erences between smaller understorey plants and mature canopyforming individuals. Th e former have less-clustered, longer, thicker and relatively narrower leaves with more clearly bipulvinate petioles, less-rounded tips and more clearly serrate margins. We do not know whether these diff erences are related to age or rather to environmental factors, e.g. stronger radiation and transpiration in the canopy. Seedlings have even narrower leaves but the very short petioles are only swollen at the base. Conspicuous cup-shaped leaf galls or their presumed scars (Fig. 2) were present in all collected specimens. All sepals and petals have a glabrous patch at the base of the otherwise hairy inner surface. Th ese glabrous portions are apparently pressed against the 10-lobed disc before anthesis. Wood density, based on three specimens, varied from 0.45-0.56 g/cm³.
Specimens examined. Accession numbers are given in parentheses, barcode numbers in square brackets. Barcodes of specimens in K and L link to specimen records in the respective databases (RBG Kew 2015, Wieringa 2015).