Areca triginticollina Heatubun, Phytotaxa 28: 24 (2011)

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Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)
This species is only known very few collections from Bukit Tiga Puluh National Park in Riau Province in South Western of Sumatra, Indonesia. (C.D.Heatubun, Seven new species of Areca (Arecaceae) in Phytotaxa 28. 2011)A

Habitat

Discussion

  • Areca triginticollina is similar to A. tunku in many respects, including the litter-trapping crown and the inflorescence sometimes bursting out from the persistent prophyll. However, they can be distinguished by inflorescence structure. Areca triginticollina has swollen-flattened rachillae, which are folded in a zigzag fashion, this corresponding to the position of the pistillate flowers; also the triads are distributed along half of the length of the rachilla. Areca tunku has erect, stiff and rigid rachillae and triads with female borne at the base of the rachillae only. Although the inflorescence structure is slightly similar to A. jugahpunya, the species are totally different in habit. (C.D.Heatubun, Seven new species of Areca (Arecaceae) in Phytotaxa 28. 2011)A

Conservation

Etymology

Description

  • Solitary, understorey tree palm. Stem 2-5 m tall, 3-4 cm diam.; internodes 3-6 cm long. Leaves 11-12 in crown, pinnate, 95-110 cm long (including petiole); sheath tubular, 20-25 cm long and 6-10 cm wide, smooth, yellowish-green to grey brown, covered in punctiform brown indumenta, sparse or very frequent near the petiole; crown shaft well defined, up to 50 cm long and 15 cm diam., sometimes swollen; petiole very short or lacking, channelled adaxially, rounded abaxially; rachis with adaxial longitudinal ridge, rounded abaxially; blade with irregularly arranged leaflets, 6-12 leaflets on each side, spacing between leaflets 6-7 cm; leaflets variable from narrow to broad, leaflets near petiole shorter than others, ca. 32 × 5 cm, slightly sigmoid, the middle leaflets about 47-55 × 4.5-8 cm, with up to 4 folds, the terminal leaflets broad, 22-33 × 7.5-14 cm, linear, tips pointed except for the terminal leaflets with notched tips, papery, slightly dark adaxially and pale abaxially. Inflorescence infrafoliar, erect, 15-22 cm long and 5-6 cm wide, protandrous, branching to 1 order (sometimes 2 at basalmost rachilla); peduncle 2-5 cm long, cream to warm yellow; prophyll 14-24 × 2.5-7 cm, borne about 1/2 way up the peduncle, lanceolate, 2-keeled, boat shaped, papery, cream to light brown, entirely enclosing the inflorescence, then splitting longitudinally and disintegrating into numerous fibres, still persistent after staminate anthesis; rachis cream-coloured; rachis bracts not persistent; rachillae ca. 13, 10-13 (-15) cm long, very stiff, flattened, wide or swollen near base, zigzag, slightly congested. Floral clusters distichous on the rachillae, complete triads including female flowers occurring from the base to half the length of each rachilla, 3?6 complete triads per rachilla. Staminate flowers small, triangular, sickle-shaped when young to elongate at anthesis, 6.9-9.3 × 2.5-4 mm, asymmetric, cream to pale brown; calyx fused, cup-shaped, ca. 2.3 × 2.5 mm at anthesis, 3-lobed, the lobes triangular about 1.6 × 1 mm; petals 3, fused near base, lanceolate, 5.1-6.7 × 1.3-2 mm at anthesis, striate; stamens 6, ca. 6.7 mm × 0.6 mm, elongated, basifixed; anthers ca. 5.3 × 0.6 mm, creamy, elongated, sagittate, shorter than filaments; filaments ca. 6.7 × 0.3 mm, joined to anther from base to tip, dark brown; pistillode absent. Pistillate flowers larger than the staminate, triangular, buds varying greatly in size depending on stage of development, 10-13 mm long and 5-6 mm wide at anthesis; calyx with 3 sepals; sepals free, strongly imbricate, ca. 7.2 × 6.4 mm at anthesis, triangular, asymmetrical; petals 3, imbricate, triangular, ca. 13 × 5 mm at anthesis; staminodes lacking. Fruits (young) green, elongate, apical stigmatic remains, mature fruits not seen. (C.D.Heatubun, Seven new species of Areca (Arecaceae) in Phytotaxa 28. 2011)A

Materials Examined