Heterospathe porcata W.J. Baker & C.D. Heatubun, Palms 56(3): 142-144 (2012)

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Distribution

Map uses TDWG level 3 distributions (https://github.com/tdwg/wgsrpd)
New Guinea present (Baker, W.J. & Heatubun, C.D. 2012: New Palms from Biak and Supiori, Western New Guinea. – Palms; Journal of the International Palm Society 56(3): 131-150)A
Recorded from only one locality on Supiori Island. (Baker, W.J. & Heatubun, C.D. 2012: New Palms from Biak and Supiori, Western New Guinea. – Palms; Journal of the International Palm Society 56(3): 131-150)A

Habitat

  • Secondary limestone forest dominated by Myristica, Intsia and Lepiniopsis at an elevation of ca. 30 m. (Baker, W.J. & Heatubun, C.D. 2012: New Palms from Biak and Supiori, Western New Guinea. – Palms; Journal of the International Palm Society 56(3): 131-150)A

Diagnosis

  • Heterospathe porcata is distinguished from other species in the genus by its inflorescence with elongate peduncle, the peduncular bract inserted in the proximal half of the peduncle, and the fruit with a bony endocarp with 6-7 longitudinal ridges. (Baker, W.J. & Heatubun, C.D. 2012: New Palms from Biak and Supiori, Western New Guinea. – Palms; Journal of the International Palm Society 56(3): 131-150)A

Conservation

  • Data deficient (IUCN 2001). Current knowledge of populations of this palm and the condition of the forests on Supiori is insufficient for a conservation assessment to be completed at this time. (Baker, W.J. & Heatubun, C.D. 2012: New Palms from Biak and Supiori, Western New Guinea. – Palms; Journal of the International Palm Society 56(3): 131-150)A

Etymology

  • Porcata, meaning ridged (Baker, W.J. & Heatubun, C.D. 2012: New Palms from Biak and Supiori, Western New Guinea. – Palms; Journal of the International Palm Society 56(3): 131-150)A

Common Name

  • Not known. (Baker, W.J. & Heatubun, C.D. 2012: New Palms from Biak and Supiori, Western New Guinea. – Palms; Journal of the International Palm Society 56(3): 131-150)A

    Description

    • Slender, ?solitary, understory palm. Stem to ca. 6 m tall, ca. 3 cm in diam.; leaf scars prominent; internodes 1-2 cm. Leaves 16 in crown; sheath open, margins eroded, not forming crownshaft; petiole ca. 50 cm long,
      adaxially channeled; rachis ca. 100 cm long, with sparse, floccose indumentum of orange-brown scales throughout; leaflets ca. 40 each side of rachis, regularly arranged, borne up to 3.5 cm apart, somewhat discolorous, basifixed ramenta scattered on proximal part of adaxial surface of midribs and major veins; middle leaflet ca. 45 cm long, 2?2.3 cm wide, linear, somewhat sigmoid at tip and base, tip narrowly attenuating, transverse veinlets inconspicuous. Inflorescence 1240138 cm long, interfoliar, elongate, brush-like, branched to 2-3 orders; prophyll ca. 39 cm long, 1.5-2 cm wide, splitting apically, with lepidote indumentum of dark scales; first peduncular bract, ca. 69 cm long, ca. 2 cm wide, similar to prophyll, splitting apically to one side, indumentum as prophyll, attached one third to halfway above the peduncle base; peduncle 102-108 cm long, 5.5-7.5 mm wide, with thin, dark brown tomentum and throughout all inflorescence branches; primary branches 9-13, to 28 cm long, 1.5-4 cm apart, with up to 14 rachillae; rachillae 10-17 mm long, 0.9-1.5 mm in diam., swept forward at an acute angle to the rachis, sinuous, with thin dark brown tomentum; rachilla bracts inconspicuous; triads 2-3.5 mm apart, spirally arranged. Male flower ca. 2 mm long, ca. 1.8 mm in diam. in young bud; sepals 3, ca. 1 mm long, ca. 1.5 mm wide, concave, imbricate; petals 3, ca. 1.5 mm long, ca. 1.3 mm wide, cucullate, valvate; stamens 6; filaments ca. 0.6 mm long, connate in a ring at base, linear; anthers ca. 0.8 mm long, ca. 0.3 mm wide, oblong, dorsifixed, connective dark; pistillode 0.6 mm long, 0.3 mm in diam., cylindrical. Female flower ca. 4 mm long, ca. 3.5 mm in diam., borne in proximal half of the rachillae only, bracteole forming conspicuous perianth-like cupule; sepals 3, ca. 2.5 mm long, ca. 3 mm wide, concave, imbricate; petals 3, ca. 3.6 mm long, ca. 2.5 mm wide, concave with short, triangular apical lobe, imbricate; staminodes ca. 2, linear, ca. 0.6 mm long; gynoecium ca. 3.5 mm long, ca. 1.5 mm in diam., ellipsoid, stigma inconspicuous. Fruit ca. 2 cm long, ca. 9 mm diam. (measured from dry material), ellipsoid, pericarp shrinking around endocarp ridges when dried, stigmatic remains eccentrically apical, red; perianth cupule clasping; endocarp ca. 2 cm long, ca. 8.5 mm in diam., ellipsoid, dark brown, bony, with 6-7 thickened, fibrous ribs radiating from the stigmatic remains and running the length of the fruit to the base. Seed immature, star-shaped in section, conforming to inner contours of endocarp; endosperm ruminate; embryo basal. (Baker, W.J. & Heatubun, C.D. 2012: New Palms from Biak and Supiori, Western New Guinea. – Palms; Journal of the International Palm Society 56(3): 131-150)A

    Materials Examined

    • Indonesia, Papua, Supiori Island: North Supiori Nature Reserve, Fanjur village, June 2001, Maturbongs et al. 680 (holotype K; isotypes AAU, BO, CANB, LAE, MAN). (Baker, W.J. & Heatubun, C.D. 2012: New Palms from Biak and Supiori, Western New Guinea. – Palms; Journal of the International Palm Society 56(3): 131-150)A

    Notes

    • Heterospathe has two centers of diversity, the Philippines and New Guinea. In New Guinea, species diversity is biased towards the eastern half of the island and montane elevations - around 90% of all New Guinea Heterospathe specimens have been collected from Papua New Guinea and more than 75% from elevations above 500 m. An undescribed species from the lowlands of an offshore island of western New Guinea is thus an unexpected discovery.
      Superficially, H. porcata is similar to Heterospathe elegans, although the nearest record for this species is some 500 km away to the south-east (Trudgen & Baker 2008). The two species share a slender habit, finely pinnate leaf and inflorescence with elongate peduncle and branches clustered near the apex. Heterospathe porcata appears to be a taller palm, recorded as 6 m in contrast to the reported maximum of 2.5 m for H. elegans. The inflorescence is also quite different, being branched to 2 or 3 orders (1 or 2 orders in H. elegans), the rachillae being finely sinuous (more irregularly so in H. elegans) and the first peduncular bract being rather long and inserted one third to halfway along the peduncle from the base (shorter in H. elegans and inserted in the distal quarter of the peduncle). Unusually, the fruit contains a thin, bony endocarp with 6 or 7 thickened, parallel, fibrous ridges running the full length of the fruit (hence the species epithet porcata, meaning ridged). These reveal themselves when the ellipsoid fruit, which are larger than the globose fruit of H. elegans, are dried and the mesocarp shrinks around the ridges. The space with the endocarp is somewhat star-shaped in cross section and, consequently, so is the seed, in contrast to the globose seed of H. elegans. Within Heterospathe, the only species with a comparable endocarp is H. longipes of Fiji, though this has much more extremely ornate structures. The combination of its geographical and elevational distribution, and almost unique reproductive morphology renders H. porcata a very surprising novelty indeed. (Baker, W.J. & Heatubun, C.D. 2012: New Palms from Biak and Supiori, Western New Guinea. – Palms; Journal of the International Palm Society 56(3): 131-150)A

    Bibliography

      A. Baker, W.J. & Heatubun, C.D. 2012: New Palms from Biak and Supiori, Western New Guinea. – Palms; Journal of the International Palm Society 56(3): 131-150