Heterospathe barfodii L.M.Gardiner & W.J.Baker, Palms (1999+) 56(2). 2012

Primary tabs

no image available

Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)
Known only from one wild collected specimen, from the lowlands of mainland Milne Bay Province, Papua New Guinea. (L.M.Gardiner, J. Dransfield, J.Marcus & W.J.Baker, Heterospathe barfodii, a New Species from Papua New Guinea in Palms (1999+) 56(2). 2012)A

Habitat

Discussion

  • The genus Heterospathe Scheff. is defined by a combination of characters that occur in other genera of tribe Areceae, rather than by any unique synapomorphies: "leaf sheath splitting to the base, interfoliar inflorescences (at least at anthesis), peduncle longer than the rachis, peduncular bract longer than the prophyll, prophyll persistent, and peduncular bracts persistent" (Norup et al. 2006). Heterospathe barfodii shares most of these characters. Although H. barfodii has a distinct crownshaft with the outermost leaf sheaths remaining largely tubular, it appears that the oldest sheath is at least partially open with fibrous margins, a condition that can be observed on inner leaf sheaths of other species of Heterospathe. It would appear that the possession of a crownshaft is a matter of degree in Heterospathe. The fact that the inflorescences are infrafoliar in H. barfodii is most likely related to the physical constraints imposed by a well-defined crownshaft.
    As noted by Norup et al. (2006), the combination of a crownshaft and persistent prophyll, as is found in Heterospathe barfodii, occurs elsewhere in tribe Areceae only in Dransfieldia, Drymophloeus, Roscheria and some species of Dypsis. Of these, H. barfodii most closely resembles a robust Dransfieldia, on account of its crownshaft, infrafoliar inflorescence, elongate peduncle and persistent prophyll. However, Dransfieldia is a much more slender palm, with slim, bullet-shaped staminate buds well-spaced along the rachillae (unlike the relatively crowded arrangement of ovoid buds along the rachillae in H. barfodii), more stamens (up to 19) and an inner whorl of erect stamen filaments (the filaments all being inflexed in H. barfodii). Dransfieldia is also restricted in geographic distribution to the far-western Papua province in Indonesian New Guinea. We have generated DNA sequence data for the two low-copy nuclear genes PRK and RPB2 from the cultivated material of H. barfodii, integrating these into the recent arecoid dataset of Baker et al. (2011) and re-analysing the data following their methods. The resulting molecular phylogeny places the species firmly within the genus Heterospathe, and although the sampling of New Guinea taxa is incomplete, resolves it in a clade with two other New Guinea taxa, H. delicatula H.E. Moore and H. elegans subsp. humilis (Becc.) M.S. Trudgen & W.J. Baker. In this revised analysis, Dransfieldia remains quite distinct from Heterospathe.
    (L.M.Gardiner, J. Dransfield, J.Marcus & W.J.Baker, Heterospathe barfodii, a New Species from Papua New Guinea in Palms (1999+) 56(2). 2012)A

Conservation

  • This palm meets the criteria for threat category Critically Endangered (CR B1ab(i,ii, iii, iv, v), C2(ai, aii), D; IUCN 2001) as it is only known from a small population at a single location, and therefore its extent of occurrence is estimated to be less than 100 km2. Similarly, the area of occupancy is estimated to be less than 10 km2, the palm is only known from one location, and the population size is suspected to number fewer than 50 mature individuals as no other individuals were seen (A.S. Barfod, personal communication). The type locality is a disturbed forest edge, along the side of a dirt road - by definition individual plants in this location are vulnerable, and the area is under threat from logging, mining and oil palm plantations. Therefore the population of this species is likely to decline unless conservation action is taken. (L.M.Gardiner, J. Dransfield, J.Marcus & W.J.Baker, Heterospathe barfodii, a New Species from Papua New Guinea in Palms (1999+) 56(2). 2012)A

Description

  • Medium, solitary palm. Stem erect to (2-)8 m tall, 7 -10 cm in diam.; leaf scars 1-2 cm wide; internodes 3-10 cm (up to 17 cm in juvenile stem); green to dark brown but upper few internodes covered with white farinaceous indumentum. Leaves 7-9 in crown; sheaths 55-67 cm long, forming a well-defined crownshaft, pale green, covered with dense, thin farinaceous white indumentum with scattered, minute, pale brown, white-edged scales; petiole 20-40 cm long, concave adaxially, bright green, indumentum as for sheath; rachis 205-240 cm long, 10-12 mm wide at midpoint; leaflets 38-56 per side, borne 4 cm apart (along mid-section of leaf), regularly arranged, in a single plane, held horizontally with tips drooping slightly, narrowly to broadly linear, leathery, singlefold but apical leaflet pair sometimes multifolded and partially joined, tapering to bifid apices, bright green, concolorous, red-brown or whitish medifixed ramenta to 5 mm long scattered on abaxial surface of proximal portion of midrib and secondary veins, transverse veinlets conspicuous, proximal leaflets 39.5-49 cm long, 1.2-2.1 cm wide, middle leaflets 67-78 cm long, 4-5.5 cm wide, distal leaflets 22-23.5 cm long, 1.5-2.4 cm wide. Inflorescence 68-99 cm long, infrafoliar, branched to 3 orders, branches spreading, deep maroon at anthesis; prophyll 25-34 cm long, 5-7 cm wide, opening apically, persistent, covered with white farinaceous indumentum; peduncular bract similar to prophyll, caducous or persistent, exserted from prophyll, insertion ca. 14 cm from base of the peduncle, enclosed within prophyll; peduncle 32-33 cm long, 20-22 mm wide; rachillae 14-36 cm long, 2.5-3 mm in diam., with ca. 6 triads per 1 cm, rachilla bracts minute to 1 mm, triangular; all inflorescence axes sparsely covered with floccose to lanate brown to pale brown indumentum, diminishing along branches. Staminate flower 2.9-3.7 mm long, 2.7-3.3 mm in diam. in bud, ovoid; 7.5-8.4 mm in diam. and deep maroon at anthesis; sepals 3, imbricate, thick, triangular, 1.1-1.5 mm long, 1.0-1.7 mm wide; petals 3, 3.0-4.0 mm long, 1.7-2.4 mm wide, valvate, triangular; stamens 6-9, 4.2-5 mm long; filaments 3-3.5 mm long, 0.4-0.5 mm in diam., fused at base for 0.4 mm to form a ring around pistillode, white, inflexed; anthers 1.2-1.9 mm long, 0.6-0.9 mm wide, medifixed; pistillode 1 mm long, 0.8 mm in diam. at base, conical, minutely trifid. Pistillate flower immature, bud ca. 4.9 mm long, ca. 2.7 mm in diam., globose-ovoid, deep maroon; gynoecium ca. 2.1 mm long, ca. 0.9 mm in diam., perianth imbricate. Fruit 1 cm in diam., spherical, surface striate, red when mature; perianth cupule clasping; stigmatic remains subapical; endocarp thin bony, dark brown; occasionally bilobed with two developed carpels or one developed and one partially developed carpel. Seed 7 mm in diam., spherical, pale brown; endosperm ruminate; embryo basal. (L.M.Gardiner, J. Dransfield, J.Marcus & W.J.Baker, Heterospathe barfodii, a New Species from Papua New Guinea in Palms (1999+) 56(2). 2012)A

Materials Examined