Areca gurita Heatubun, 2011

Heatubun, Charlie D., 2011, Seven New Species of Areca (Arecaceae), Phytotaxa 28, pp. 6-26 : 15-18

Areca gurita Heatubun , sp. nov.

Palma elegantissima Borneensis caespitosa, A. minutae Scheff. habitu similis, inflorescentia octopiformi, rhachillis recurvatis, floribus secundis ab imum usque ad apicem et spiraliter ad apicem, floribus staminatis alternatis, antheris connectivo lineare distincta.

Type :––CULTIVATED. Borneo , Sarawak: Semengoh Forest Arboretum , Palm Collection, 01º 24.061' N 110º 19.443' E, 31 March 2008, Heatubun & Kuda 896 (holotype K!, isotype SAR!) .

Clustering with many suckers, small, undergrowth palmlet. Stem to 1.5 m high, 1 cm in diam.; internodes 3 cm long, smooth and green near the crown, light brown to whitish near the base. Leaves ca. 11 in crown, pinnate, ca. 32 cm long (including petiole); sheath tubular, ca. 20 cm long and 1−2 cm wide, light brown to brown, and light brown when dried; crown shaft well-defined, up to 30 cm long and 1−2 cm diam.; petiole ca. 3 cm long, channelled adaxially, rounded abaxially; rachis very slender with adaxial longitudinal ridge, rounded abaxially; blade with irregularly arranged leaflets, 2−4 leaflets on each side, spacing between leaflets 1.5−3 cm; leaflets from narrow to broad, leaflets near petiole ca. 15 × 3 cm, slightly sigmoid, tip obligue acuminate, the middle leaflets about ca. 12 × 2 cm, linear with 1 vein, the terminal leaflets broad, flabellate, ca. 15 × 6 cm, margin toothed, papery, concolorous. Inflorescence infrafoliar, erect, small and compact, to 10 cm long and to 10 cm wide, protandrous, always branching to 1 order; peduncle short to 3 cm, covered in thick brown indumentum; prophyll persistent; rachis also covered in rusty brown indumentum; rachillae 3−8 (including main axis), divaricate, to 10 cm long and ca. 5 mm wide near base, recurved. Floral clusters uniseriate, but spiral at the tip of rachillae, 1–3 complete triads including female flowers occurring near the base of rachilla and more (5–15 flower clusters) on terminal rachilla. Staminate flowers small, triangular to rounded, 2−2.5 × 1.5−1.80 mm, asymmetric, white to cream; calyx fused, triangular cup-shaped, ca. 1.5 × 1 mm before anthesis, 3-lobed, light brown to brown; petals 3, fused near base, obovate, 2−2.2 × 1.2−1.5 mm at anthesis, white to cream-coloured; stamens 6, 1.5−1.7 mm × 0.5 mm, basifixed; anthers ca. 1.2 × 0.5 mm, cream-coloured, sagittate, longer than filaments; filaments ca. 0.5 × 0.2 mm, dark brown, connective linear; pistillode absent. Pistillate flowers larger than the staminate, triangular, ca. 5.5 mm long and 3.5 mm wide before anthesis, greenish; sepals 3, strongly imbricate, 4–4.5 × 4 mm before anthesis, somewhat triangular, asymmetrical; petals 3, imbricate, triangular, ca. 4.5 × 4 mm before anthesis; lacking staminodes; gynoecium ca. 4 mm (including stigma). Fruits (young) white with green at the tip, obovoid with beak, ca. 2 cm long and 1 cm wide (young fruit still in development), apical stigmatic remains, mature fruits not seen. ( Figures 5 & 6B–D ).

Distribution: —This species is known from several collections in Bintulu Division and Miri Division of Sarawak.

Habitat:––Heath forest to montane forest from an elevation 80–750 m above sea level.

Local Name and uses: —Not recorded.

Conservation status: ––Endangered (EN B2ab). This species is known from only four localities in the wild, at least one of which may have been destroyed. Only one locality falls within a protected area (Lavang forest). Areca gurita is cultivated in Semengoh Forest Arboretum near Kuching where the palm grows well and sets fruit. However, further population study is needed to assess the conservation status of this palm, considering the trend of deforestation rates in the region.

Etymology: —The specific epithet is gurita , the Malay word for octopus, which reflects the curious appearance of the inflorescence of this species.

Additional specimens examined: — MALAYSIA. Borneo, Sarawak: Bintulu Division, Bukit Kana, Ulu sg. Sanggan, Tatau , 25 March 1995, Yii & Jugah S . 71688 ( K!, KEP, SAR!); Lumut Range , 22 September 1992, Mohtar & Yii S . 65877 ( SAR!); Sabal, Logging road, Sabal sisi, 18 February 1995, Runi et al. S . 71203 ( K!, KEP, L!, SAR!); Miri Division, Lavang Forest Protected Area , 24 April 1994, Yii et al. S . 67563 (KEP, SAR!).

Discussion: –– Areca gurita is similar to A. minuta in habit, leaves and general appearance. However, they can easily be differentiated by inflorescence structure and flower arrangement. The rachillae of A. gurita are recurved and resemble octopus tentacles, and the flowers are mostly uniseriate. The rachillae are numerous (3–8 including terminal rachilla) and the anther connective is also linear, rather than the rachillae being few (usually with only 3 rachillae), the flowers arranged spirally on the rachillae and the furcate connective in A. minuta .

The flower arrangement in A. gurita appears to be a modification from spiral to uniseriate; spirally arranged flowers still persist at the tip of rachillae. The rachillae are expanded on one side and display all flowers in the one direction.

Figures

FIGURE 5. Areca gurita. A. Habit. B. Leaf. C. Inflorescence showing staminate and pistillate flowers in bud and their arrangement on rachillae. D, E. Staminate flower whole and in section. F. Fruit still attached to rachilla. Scale bar: A = 31.5 cm; B = 3 cm; C = 3.6 cm; D, E = 1.2 mm; F = 1.3 cm. All from Heatubun 896. Drawn by Lucy T. Smith.

FIGURE 6. A. Infructescence of Areca dransfieldii in Lambir National Park showing the stiff, straight rachillae with young fruits. B. Habit of Areca gurita with very few clustering stems and shoots, the palm cultivated at Semengoh Forest Arboretum near Kuching, Sarawak. C. Inflorescence of Areca gurita with the octopus tentacle-like rachillae. D. Young fruits of Areca gurita. Photos: A (John Dransfield), B–D (Charlie D. Heatubun).