Adonidia maturbongsii W.J.Baker & C.D.Heatubun, Palms 56(3): 134-141 (2012)

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Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)

Habitat

Diagnosis

Conservation

Common Name

  • Manjek (Biak dialect)

    Etymology

    Description

    • Medium, solitary, mid-story to emergent palm. Stem 10-15 m tall, 10-20 cm in diam., tapering towards apex, surface brown with white blotches, leaf scars prominent, internodes 2-4 cm apart. Leaves ca. 10 in crown, arching; sheath 60-70 cm long, pale, dull green, with thin grey scurfy indumentum with scattered purple-brown scales, somewhat eroded or fibrous at mouth, forming crownshaft 80-90 cm × 10-12 cm; petiole 26-45 cm long, channelled adaxially, rachis 2.5-3 m long, indumentum as on sheath; leaflets 25-30 pairs each side of the rachis, regularly arranged (or somewhat subregularly), in one plane, drooping or pendulous in emergent individuals, slightly discolorous, with persistent reins attached to lowermost pair of leaflets, with minute brown punctate scales and scattered medifixed ramenta abaxially; middle leaflets 40-49 cm long, 9-12 cm wide, oblanceolate, cucullate, apex obliquely praemorse, concave, transverse veinlets inconspicuous; terminal leaflets linear or narrowly elliptic, apex truncate, praemorse. Inflorescence 60-70 cm long, infrafoliar, protandrous, divaricate, patent, deflexed in fruit, branched to 4 orders, axes white, rubbery, with caducous floccose orange-brown indumentum when young; prophyll 24-26 cm long, 6-8 cm wide, greenish white, splitting apically, caducous later; first peduncular bract 31-35 cm × 5-7 cm, attached 15-20 mm above prophyll insertion, exserted from prophyll apex and enclosing inflorescence prior to anthesis, caducous later; peduncle 8-14 cm long, 2-2.5 cm wide, scurfy indumentum of black-brown scales basally; primary branches 25-28, longest primary branch (basalmost) 40-65 cm; rachillae 8-19 cm long, 1.5-3.5 mm in diam., triads 3-9 mm apart, spirally arranged. Staminate flower 6.5-8 mm long, 2.5-3.2 mm in diam. in bud; sepals 2-2.4 mm long, ca. 3 mm wide, rounded, thickened; petals 7-7.5 mm long, ca. 3 mm wide, bony, narrowly elliptic; stamens 30-32, 4.5-6 mm long; filaments 1.5-4 mm long, briefly connate at base, awl-shaped; anthers 3-3.8 mm long, 0.5-0.8 mm wide, dorsifixed near the base, dehiscence latrorse, connective dark; pistillode long, 4-4.5 mm wide, thickened, rounded; petals 4-4.5 mm long, 3-3.5 mm wide, similar to sepals; staminodes few, minute, tooth-like; gynoecium ca. 4 mm long, ca. 3 mm in diam., pyriform, stigmas at anthesis not seen. Fruit 24-31 mm long, 14-16 mm in diam., ellipsoid, ripening through orange to red, perianth cupule clasping; endocarp 23-30 mm long, 12-12.5 mm in diam., straw-colored with thick longitudinal fibers, closely adhering to seed. Seed 14-20 mm long, 9.5-12 mm in diam., ellipsoid; endosperm ruminate; embryo basal. (W.J.Baker & C.D.Heatubun, New Palms from Biak and Supiori, Western New Guinea in Palms (1999+) 56(3). 2012)A

    Materials Examined

    • Indonesia, Papua, Biak Island: forest on the road side, main road from North Biak Nature Reserve to Biak town, July 2009, Heatubun et al. 971 (holotype K, isotypes BO, FTG, MAN, NY); North Biak Nature
      Reserve, Sansundi village, September 1998, Maturbongs et al. 559 (BO, K, MAN), Maturbongs et al. 560 (BO, K, MAN); Samber forest, July 2009, Baker et al. 1336 (BO, K, FTG, MAN), Baker et al. 1338 (BO, K, FTG, MAN); locality uncertain (given incorrectly on the label as Merauke district, but number sequence
      indicates the collector was active in Biak), June 2001, Maturbongs et al. 686 (AAU, BO, FTG, K, MAN). (W.J.Baker & C.D.Heatubun, New Palms from Biak and Supiori, Western New Guinea in Palms (1999+) 56(3). 2012)A

    Notes

    • It has been known for some time that an undescribed species from subtribe Ptychospermatinae occurs on Biak (Baker pers. obs. 2000, Zona 2000). The species appears to have been first recorded by Greg Hambali who introduced it to cultivation as Drymophloeus "veitchioides", an unpublished name under which it persists in some collections today. However, new molecular phylogenetic data provide evidence that the species is most closely related to Adonidia merrillii, the sole species of a hitherto monotypic genus restricted to parts of the Philippines and far northern Borneo (Zona et al. 2011). Although the study was based on only two DNA regions and the relationships only moderately supported by the data, we describe the new species as Adonidia maturbongsii as the best solution given the available data and because of morphological similarities discussed below.
      Generic limits in subtribe Ptychospermatinae are fine and sometimes problematic (Zona 1999, Dransfield et al. 2008), as evidenced by the initial, but erroneous assignment of this new species to Drymophloeus, a genus that has experienced substantial changes in circumscription recently (Zona et al. 2011). Nevertheless, A. maturbongsii and A. merrillii share a combination of features that lends support to a close relationship between the two. Both species are moderately robust palms of limestone habitats that bear white inflorescences branched up to four orders. They produce red fruit with endocarps covered in pale, flattened, longitudinal fibers interspersed with finer fibers and seeds with ruminate endosperm. Nevertheless, A. maturbongsii is very different from its congener, most obviously in its arching leaf with broad, pendulous leaflets in a single plane with wide, concave, praemorse tips (in contrast to the ascending, narrower leaflets in slightly different planes with less conspicuously praemorse tips in A. merrillii). In addition, the staminate flowers of A. maturbongsii contain 30-32 stamens compared to 45-50 in A. merrillii.
      Adonidia merrillii is a geographically disjunct species, occurring to the west of Wallace's Line whereas all other Ptychospermatinae occur to the east of this important biogeographic interface (Baker & Couvreur 2012). The expansion of the genus elaborates this biogeographic story. The link between New Guinea and the Philippines has been explained by westward stepping-stone dispersal along the Philippine-Halmahera arc during the Neogene (Zona et al. 2011), which may also account for similar biogeographic links in other taxa, such as the palm genera Heterospathe and Orania, and Sararanga in the Pandanaceae (Baker et al. 1998, Norup et al. 2006). (W.J.Baker & C.D.Heatubun, New Palms from Biak and Supiori, Western New Guinea in Palms (1999+) 56(3). 2012)A