Pandanus belepensis Callm. & Munzinger, 2011

Callmander, Martin W., Munzinger, Jérôme & Stone, Benjamin C., 2011, Pandanus belepensis (Pandanaceae), a new species from the Belep Archipelago (New Caledonia), Phytotaxa 38, pp. 36-40 : 37-40

Pandanus belepensis Callm. & Munzinger , sp. nov., Fig. 2 A-G

Type :— NEW CALEDONIA. Belep Archipelago : Ile Art, plateau Sud, antenne, 19º44'59"S, 163º40'42"E, 25.VIII.2009, fr., Munzinger, Swenson & Barrabé 5736 (holotype P [ P00722527 , P00722529 , carpo. coll.]!, isotype NOU [ NOU051020 , NOU050401 , carpo. coll.]!) .

Haec species ab omnibus congeneris novocaledonicis syncarpio parvo (ca. 10 × 9 cm), pileo in parte apicali convexo atque stigmatibus 2 ad 5 subcircularibus usque adpresse reniformibus in centro pilei arcte crebris ad stylum leviter (1–2 mm) elevatis interdum adpressis tum cephalii apicem (extremum distale) spectantibus differt.

Small tree, trunk 2 m tall, 8 cm in diameter, branched. Leaves ensiform, attenuate in the distal part, apex sharply acute, 65–120 cm long, 2.0– 2.5 cm wide; old leaves not persistent on branch; dry leaves thin but firmcoriaceous; longitudinal veins visible on both surfaces; marginal prickles borne from 4–8 cm above the base to the apex, antrorse, 0.25–0.5.0 mm long in the lower third, 1.5–4.0(–6) mm apart, 0.5 mm long in the mid third, 2–6 mm apart, to 0.3‒0.8 mm long in the distal third, 0.5‒2.0 mm apart, subappressed; midrib armed from 20–25 cm beyond the base, prickles <0.4 mm, randomly disposed and appressed in the proximal half, then similar in size and spacing to those on the adjacent margins. Apical ventral pleats with prickles in the proximal 8–12 cm, c. 0.4 mm, antrorse, irregularly spaced (2–35 mm), and often lacking over longish intervals; sheath 5–6 cm long, c. 2.5 cm wide at apex, 3.5 cm at base. Infructescence terminal, the solitary syncarp on a straight peduncle; syncarp 9 × 10(–15) cm in diameter, sub-ovoid to sub-globose; peduncle 16 cm long, 1.5 cm wide at apex, 0.7 cm in the middle, straight, trigonous, veins visible, bracts to as many as 6 on entire peduncle. Drupes c. 140, connate in the mature syncarp, c. 1.4–2.1 × 3.0 × 1.0– 1.4 cm, 2- to 5-celled, 5- or 6-angled; pileus convex, ⅓ superior portion free; stigmas 2‒5, c. 1 mm wide, subcircular to appressed reniform, closely gathered in the center of the pileus, contiguous, slightly heightened (1–2 mm) on style and sometimes appressed and facing the apex of the cephalium; endocarp dense, dark brown, bony, walls mostly 1–2 mm thick, c. 1 cm long; seed locule oblong, 8 × 2–3 mm; upper mesocarp cavernous, lower short-fibrous. Staminate flower unknown.

Distribution:— Pandanus belepensis is known only from Ile Art and Niémane, two islands in the Belep Archipelago, NW New Caledonia ( Fig. 1 ).

Discussion:— Pandanus belepensis has a rather small syncarp coupled with thin and short leaves, an uncommon combination of features among New Caledonian members of the genus. Indeed, only two other species are so small in their overall dimensions and bear multicarpellate drupes: P. decumbens (Brongn.) Solms and P. neocaledonicus Martelli. Our new species can be easily distinguished from them, however, by the dimension of its leaves, the shape and dimension of its syncarp, the shape of the drupe apex and the arrangement of its stigmas ( Table 1 ). Pandanus belepensis is placed in P. sect. Brongniartia B.C.Stone , an endemic New Caledonian group of eight endemic species that also includes P. decumbens and P. neocaledonicus , as well as P. balansae (Brongn.) Solms , P. bilinearis H.St.John , P. cavatus H.St.John , P. pancheri (Brongn.) Solms , and P. reticulatus Vieill. Members of this section are characterized by having carpels that are predominantly connate in 2- to several-celled drupes, and stigmas oriented vertically (or mostly so) on the ventral margin of the pileus, but not salient and only slightly (or not) overtopped by the stylar apex.

Additional specimens examined (paratypes):— NEW CALEDONIA. Ile Art , plateau Sud , 9 Dec 1975, fr., Jaffré 1591 ( BISH, NOU [ NOU048379 , NOU048378 ], PH [ PH 00037676]); Ilot Daouinth , Niéname , 23 Aug. 1978, fr. Veillon 3681 ( NOU [ NOU048534 ], PH [ PH 00072761]); Ile Art , plateau Sud, 24 Aug 1978, fr., Veillon 3698 (NOU [NOU006623, NOU050521, carpo]); Ile Art, Pairomé Sud, 26 Aug 1978, fr., Veillon 3711bis ( NOU [ NOU048374 , NOU050518 , carpo. coll.]) .

Conservation status:—With only 2 subpopulations known with an estimated total of less than 1000 individuals, an EOO of 27 km 2 (calculation following Callmander et al. 2007), Pandanus belepensis is assigned a preliminary status of Vulnerable (VU D1) following the IUCN Red List Categories and Criteria ( IUCN 2001).

Figures

FIGURE 1. Map of New Caledonia showing the Belep Archipelago (framed) and the sites at which Pandanus belepensis has been collected (circles), grey represents ultramafics substrates.

FIGURE 2. Pandanus belepensis Callm. & Munzinger. A. Proximal part of a leaf; B. Median and distal portion of a leaf; C. Syncarp; D. Longitudinal section of a drupe; E. Lateral view of a drupe. F. Apical view of a drupe. G. Detail of stigmas. A–G: Munzinger, Swenson & Barrabé 5736, holotype P; Scale bars: A–F, 2 cm; G, 0.5 cm; Drawing: C. Chatelain.