Pandanus grayorum Callmander &amp; Gallaher &amp; Buerki &amp; Zich &amp; Field 2021, sp. nov.
Creators: name: Callmander, Martin W.
name: Gallaher, Timothy
name: Buerki, Sven
name: Zich, Frank A.
name: Field, Ashley R.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Pandanales
Pandanaceae
Pandanus
Pandanus grayorum

description: <i>Pandanusgrayorum</i> Callm., Buerki &amp; Gallaher, sp. nov. (Fig. 1.) <i>Type:</i> AUSTRALIA. Queensland: Cook District, Jubilee Road, off Flying Fish Point Road, Innisfail, 17 ° 290460 S, 146 ° 020260 E, 8 m, 4.x.2018, fr., <i>B. Gray 9976</i> (holo: G 00446800! [3 sheets + carpological specimen]; iso: BISH!, BRI, CANB, CNS 148706! [3 sheets + carpological specimen]). <i>Pandanus</i> sp. (Russell River) in W.E.Cooper &amp; W.T.Cooper, <i>Fruits Austral. Trop. Rainforest</i> 390 (2004). <i>Diagnosis</i> <i>Pandanus grayorum</i> is distinguished from <i>P. gemmifer</i> in having larger crown leaves (210 <i>–</i> 280 × 7 <i>–</i> 8 cm <i>v</i>. 170 <i>–</i> 230 × 5 <i>–</i> 6 cm in <i>P. gemmifer</i>) and syncarps (35 <i>–</i> 40 × 18 <i>–</i> 22 cm <i>v</i>. 23 <i>–</i> 25 × 10 <i>–</i> 18 cm); apex of phalanges flat or slightly domed at apex, divided by apical sinuses ~ 0.5 cm deep into small, often truncate pyramids as many as there are carpels (<i>v</i>. rounded to the stigmatic cluster, 12 <i>–</i> 15 mm wide with narrow apical central sinuses restricted to the central cluster); stigma on apex or on the edge of the slightly truncate apical face of each pyramid (<i>v</i>. on proximal face of the central apex cluster). <i>Description</i> <i>Tree</i> up to 9 m tall, stem with conical nodules, prop roots at base up to 50 cm high, upper branches (and sometimes stem) producing axillary sprouts (plantlets). <i>Leaves</i> 210 <i>–</i> 280 cm long, 7 <i>–</i> 8 cm wide in the middle, ~ 9 cm wide near the sheath, gradually attenuate in the upper part, coriaceous; longitudinal veins visible on both surfaces; marginal prickles beginning at 7 <i>–</i> 9 cm above the base and extending to the apex, antrorse, 5.5(<i>–</i> 6) mm in the lower third, 5(<i>–</i> 10) mm apart, to 2 <i>–</i> 5 mm long in the mid-third; 3 <i>–</i> 5 mm apart, up to ~ 1 mm long in the distal third, 2 <i>–</i> 3 mm apart; midrib armed in the upper 1/4, prickles 4 <i>–</i> 5 mm long), irregularly disposed (3 <i>–</i> 10 mm) in the middle, then regularly disposed, spaced (2 <i>–</i> 5 mm) as long as on the marginal in the distal 1/3; sheath 5 <i>–</i> 9 cm long, ~ 9 cm wide at apex, ~ 10 <i>–</i> 11 cm wide at base. <i>Infrutescence</i> terminal, a solitary syncarp on a curved peduncle; syncarp 35 <i>–</i> 40 × 18 <i>–</i> 22 cm, oblong to obovate, bright red at maturity; peduncle ~ 60 <i>–</i> 70 cm long, 2 cm wide at apex, trigonous, veins visible, first bract borne just above the base of syncarp, 8 bract scars along peduncle and the remaining bracts crowded at the base of the syncarp. Phalanges, 60 <i>–</i> 80 per syncarp, 6 <i>–</i> 8(<i>–</i> 9) cm high, 4 <i>–</i> 5(<i>–</i> 6) cm wide, 2.5 <i>–</i> 3.5 cm thick, 4 <i>–</i> 6 angled; carpels (8 <i>–</i>) 12 <i>–</i> 18(<i>–</i> 20), incompletely united, free in the upper ~1/3 <i>–</i> 1/2, tapering to the base; pileus flat or slightly domed at the apex, divided by apical sinuses ~ 0.5 cm deep into small, often truncate pyramidsasmanyastherearecarpels. <i>Stigma</i> 1 percarpel,oblique to vertical, generally reniform, sometimes deltoid on apex or on the edge of the slightly truncate apical face of each pyramid; endocarpbony, inlower 2/3, marginsup to 5 mm wide, 1.2 <i>–</i> 2.5 cm long in the centre, 1 <i>–</i> 2 cm wide; seed locule oblong, 1.5 <i>–</i> 2.5 × 0.5 <i>–</i> 1 cm, superior and inferior mesocarp thick and fibrous. <i>Staminate inflorescence</i> terminal, pendent, creamy white, up to 76 cm long, a three-sided raceme of spikes; peduncle fleshy, flaccid and soon disintegrating; lowest floral bract 67 × 4.8 cm, margins finely toothed, apex long-subulate, median bract 31 × 4.2 cm, with fine marginal prickles, basal floral bracts extending longer than distal floral bracts; spikes dense, cylindric, 6 <i>–</i> 10 × 2.5 <i>–</i> 4 cm, with manystaminate flowers; each spike of a fleshy central axis with stemonophore 10 <i>–</i> 13 mm longeach bearing 20 <i>–</i> 26 stamens; stamens with filament 1 <i>–</i> 2 mm long, anthers 2.5 <i>–</i> 4.5 × 0.8 <i>–</i> 1.2 mm, including an apiculus 0.3 <i>–</i> 0.5 mm. (Fig. 1.) <i>Distribution</i> This species is known from the Wet Tropics of north-eastern Queensland on and near the banks of the lower reaches of the Mulgrave, Russell, Alice, Johnstone and Moresby rivers and associated subcoastal flood plains (Fig. 2). Plants identified as <i>P. grayorum</i> have been observed in the Ella Bay, Moresby Range and Russell River National Parks and Etty Bay Conservation Reserve but most of the distribution occurs in fragmented remnants among agricultural land, suggesting its previous distribution may have been wider. It occurs in sympatry with <i>P. solms-laubachii</i>, but is parapatric with <i>P. gemmifer</i>, which occurs in the mid-upper reaches of the adjacent Barron, Tully and Herbert River systems to the north and south, on the Atherton Tableland, and on the McIlwraith Range on Cape York Peninsula. <i>Habitat and ecology</i> <i>Pandanus grayorum</i> occurs in lowland rainforest, specifically simple to complex mesophyll vine forest, riparian gallery forest and rainforest margins with mangrove estuaries or <i>Melaleuca-</i> dominated woodlands. It occurs near large river banks and associated small creeks, moist gullies and tidal estuaries near sea level. Reproduction is both via seed and from vegetative propagules, which form a localised colony of trees. The vegetative propagules float and can be dispersed in fresh and tidal waters. They are covered in sharp curved hooks and are potentially zoochorous. <i>Pandanus grayorum</i> can occur as a subcanopy, canopy or in open areas as an emergent tree. <i>Phenology</i> Flowering occurs in October to January, with fruit developing over 1 year to ripen the following October through December. Field observations suggest that there are locally male- or female-biased stands, with an overall female bias across the whole population. Vegetative propagules are produced all-year round. <i>Conservation status</i> <i>Pandanus grayorum</i> is known from few collections from several populations along rivers banks and small creeks. On the basis of collection and observation records, it has an extent of occurrence (EOO) of 231 km 2 and an area of occupancy (AOO) of 28 km 2. Most records are from localities outside national parks. No threats were observed at the known localities; however, adjacent areas are road reserves and agricultural landscapes where disturbance and clearing has occurred and may continue into the future, so it is conceivable that populations may be damaged by future activities. A preliminary assessment suggests the IUCN rating of Vulnerable [VU B1ab(iii, iv)+B2ab(iii, iv)], using the IUCN Red List Categories and Criteria (International Union for Conservation of Nature 2012). <i>Etymology</i> This new species is named in honour of Joy and Bruce Gray. Bruce was formerly a technical officer with CSIRO in Atherton and has collected extensively in remote areas of northern Queensland. Over his career, Bruce has made a significant contribution to the knowledge of the northern Queensland flora through his herbarium collections, discovered many new species, and made the type collections of 114 species, in addition to the one described here. Joy and Bruce welcomed the first author with a wonderful hospitality in Atherton in 2017 and Joy’ s support of Bruce has in effect enabled so many of Bruce’ s endeavours, including an epic trip to the tip of Cape York Peninsula in 2017. The first author finally dedicates this new <i>Pandanus</i> species for Bruce’ s 80th birthday. <i>Notes</i> Vegetative propagation in the genus <i>Pandanus</i> has been recorded in Australia and Madagascar: ‘small branchlets develop near (the) apex of branches, then drop off; these act as vegetative propagules’ (Stone 1970, p. 127). This vivipary is known in three species in Madagascar (Guillaumet 1972), but it remains rare. The active vegetative propagation in <i>P. grayorum</i> and <i>P. gemmifer</i> is so vigorous on aerial branches that they can easily be identified in the field. Fig. 2. Distribution map of <i>Pandanus grayorum</i> and <i>P. gemmifer</i> in north-eastern Queensland. <i>Pandanus grayorum</i> occurs in close parapatry with <i>P. gemmifer</i> (Fig. 2, 3), with <i>P. grayorum</i> occurring on the lower reaches of the Mulgrave, Russell, Alice, Johnstone and Moresby river systems, whereas <i>P. gemmifer</i> occurs on the Barron River system to the north and the Tully and Herbert river systems and nearby drainages to the south (Fig. 2). The two species are distinguished by the dimensions of their leaves and syncarps and the morphology of their phalanges (Table 1). <i>Pandanus grayorum</i> occurs in close sympatry with <i>P. solmslaubachii</i> (Fig. 4) and shares a somewhat similar tree architecture. <i>Pandanusgrayorum</i> is readily identified by the presence of axillary buds developing into plantlets, which are absent in <i>P. solms-laubachii. Pandanus grayorum</i> also lacks the dense ascending rootlets present in <i>P. solms-laubachii</i>. The two species aredistinguished by thedimensions of their leaves, shape of syncarps and the morphology of their phalanges (Table 1, Fig. 1, 4). The leaf form of <i>P. grayorum</i> is more arcuate and the leaves are glossy, whereas in <i>P. solms-laubachii</i> the leaves are more straight and folded and are moderately glaucous. The genetic and morphological similarities among <i>P. gemmifer</i>, <i>P. grayorum</i> and <i>P. solms-laubachii</i> suggest that hybrid speciation may have played a role in the diversification of these species (Gallaher <i>et al</i>. 2015). <i>Pandanus grayorum</i> is the second taxon to be described that shares characteristics of both <i>Pandanus</i> section <i>Austrokeura</i> and <i>Australibrassia</i> (however, these sections were not retrieved as monophyletic groups in the molecular phylogeny, which might suggest that these characters evolved independently in this group; Buerki <i>et al</i>. 2012; Gallaher <i>et al</i>. 2015). Both phylogenomic and population genetic studies, coupled with field observations, are recommended to clarify species delimitations within this challenging group of Pandanaceae. <i>Additional specimen examined</i> Australia. Queensland: Harveys Creek, swamp forest, 17 °15035.0000 S, 145 °55014.0000 E, 23.IX.1971, <i>S.T. Blake 23631</i> (BRI, CANB); Bellenden Kerlanding, Russell River NP, 17 °1602200 S, 145 °5605100 E, 5 m,fr., <i>A.Field &amp; F. Zich 5015</i> (BRI, CNS, G); Polly Creek, Garadunga, in road reserve near junction of Polly Creek road and Jubilee Road, 17 °2900200 S, 146 °0200100 E, 12 m, fr., <i>A. Field &amp; F. Zich 5017</i> (BRI, CNS, G); Nind’ s Creek, Coquette Point, in road reserve of Coquette Point road abutting Moresby Range NP, 17 ° 3200200 S, 146 °0304200 E, 1 <i>–</i> 2 m, fr., <i>A. Field &amp; F. Zich 5018</i> (BRI, CNS, G); Moresby River tributary, in road reserve of Bruce Highway between Danesi Road and Croatto Road, 17 °3605400 S, 146 °0105000 E, 9 m, staminate fl., <i>A. Field &amp; F. Zich 5019</i> (BRI, CNS, G); Etty Bay, 17 ° 330 S, 146 °050 E, 7.XII.2011, fr., <i>T. Gallaher 337</i> (BISH, HAW); Russell River, below Russell River boat camp, 17 °1602100 S, 145 ° 5605400 E, 7 m, 13. XII.2017, fr., <i>B. Gray 9955</i> (BRI, CNS, G); Russell River NP, Russell River road, 17 ° 1602800 S, 145 °5605000 E, 3 m, 29.X.2003, fr., <i>B. Gray 8831</i> (BRI, CANB, CNS).
description: Published as part of <i>Callmander, Martin W., Gallaher, Timothy, Buerki, Sven, Zich, Frank A. &amp; Field, Ashley R., 2021, Pandanus grayorum (Pandanaceae), a new species endemic to north-eastern Queensland (Australia), pp. 327-335 in Australian Systematic Botany 34</i> on pages 328-333, DOI: 10.1071/SB20033, http://zenodo.org/record/5643372
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