Balaka streptostachys D.Fuller & Dowe, Palms (1999+) 43. 1999: 10

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Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)
Fijipresent (World Checklist of Arecaceae)B
Fiji. Vanua Levu, known from a single location S of Labasa on the logging road toward Mt. Sorolevu, at 300 m elevation. (D. Fuller, A New Species of Balaka from Fiji. 1999)A

Discussion

  • Balaka streptostachys is distinguished by its comparatively greater trunk diameter, to ca. l0 cm, than that of similar species such as B. microcarpa and B. macrocarpa. The inflorescence is distinctive in that the rachillae are densely tomentose, have 40˚-60˚ twists at intermittent intervals, and are angular in cross-section. Triads are ranked distichously, three to eight per section between the twistsi n the rachilla.T he endocarpa nd seeda re ridged and angular as with other Balakaspecies, though the arrangement with a single prominent longitudinal ridge, extended "wings" and quadrangular in cross-section is distinctive. An informal description of this species was included under the name of Balaka "robusta" in Fuller (1997) and again in Doyle and Fuller (1998). The species was first observed by Timoci Bulitavu, while working on construction of a logging road. Subsequently he showed it to palm horticulturist, Dick Phillips of Suva, Fiji, in early 1994, and again to Phillips along with DF and Will McClatcheyin 1995. (D. Fuller, A New Species of Balaka from Fiji. 1999)A

Diagnosis

  • Palma, Balakae microcarpae et B. macrocarpae affinis, sed truncus robustior usque ad 10 cm diametro. Inflorescentia usque ad 1.5 m longa. Rachilla trigona asymmetrica, tortilis, tortis 40˚-60˚ intermittentibus, tortis 3-5 in quoque rachilla. Flores in 3-8 triadibus distichis inter tortos in foveis vadosis. Flos staminatus albastro tubernatus, 20-35 stamina. Fructus 18-25 mm longus, B-14 mm latus. Apex endocarpi aliquantum rostrata, pagina endocarpi canalibus vadosis irregularibus. (D. Fuller, A New Species of Balaka from Fiji. 1999)A

Biology And Ecology

  • Grows as an understory palm in lower montane rainforest in a boggy area. Balaka streptostachys ocurs as an understory palm species in mixed evergreen-lower montane rainforest. The single known population is growing on very wet, spongy ground in a flat section of the Mt. Sorolevu foothills. This area receives well over 3000 mm ofrain per year. The associated vegetation includes the palms Alsmithia longipes H.E. Moore (new island record McClatchey and Fuller 1101/191, 13 May 1995, and FTG, SUVA]), Balaka macrocarpa Burret and Physokentia thurstonii (Becc.) Becc. Higher up the slopes starting at c. 500 m large numbers of Gulubia microcarpa Essig (new island record McClatchey and Fuller 1117/210, l7 May 1995, FTG, SUVA]) can be found and Clinostigma exorrhizum (H. Wendl.) Becc. occurs above 900 m on the slopes and the top of Mt Sorolevu. (D. Fuller, A New Species of Balaka from Fiji. 1999)A

Conservation

  • Proposed for IUCN Red List threatened category - Critically Endangered. There are 50-60 adult trees in the single known population of this unusual palm. This area has been selectively logged, and future logging is imminent. Dick Phillips (personal communication) has two seedlings of this taxon in cultivation in Fiji. (D. Fuller, A New Species of Balaka from Fiji. 1999)A

Etymology

  • From the Greek strepto (twisted) and stachys (spike) in reference to intermittent 40˚-60˚ twists in the rachilla, with the sections between the twists otherwise straight. This character has not been observed in other species of Balaka. (D. Fuller, A New Species of Balaka from Fiji. 1999)A

Uses

  • Ethnobotany. No native Fijian name or uses for this palm have been recorded. (D. Fuller, A New Species of Balaka from Fiji. 1999)A

Description

  • Solitary palm, trunk erect, 4-7 m tall, dbh 7-10 cm, base not expanded, internodes congested, dark green to grey with age, nodes conspicuous, light green-brown. Leaves eight to ten in the crown, held erect, slightly arcuate, regularly pinnate, to 3 m long including petiole and leafsheath, adaxially mid green, abaxially olive green; petiole 35-45 x 2.5-3.5 cm wide, adaxially concave, abaxially rounded, densely tomentose with scattered long dark scales; leafsheath tubular, split longitudinally opposite the petiole in the upper quarter, 30-50 cm long, abaxially green-light brown, densely tomentose with scattered dark scales, adaxially white, glabrous, margins at the apex lacerate-fibrous, fibers coarse and thick; rachis densely tomentose with scattered dark scales, proximally channelled, becoming ridged distally adaxially, abaxially rounded proximally, flattened distally, diamond-shaped in cross-section at mid rachis. Pinnae in one plane, regularly arranged, sub-opposite, 18-22 per side, obliquely truncate at the apex, apically dentate; mid-leaf pinnae elongately falcate, 83-95 x 6-8 cm wide, tapered from the middle toward the apex and the base; basal pinnae 90-110 x 6-7 cm wide; distal pinnae increasingly elongate to compactly cuneate toward the leaf apex, apical pair basally joined for one-sixth to one-fourth their length; mid rib prominent on both sides in all pinnae, secondary ribs almost as prominent abaxially only, two to six each side of pinna, marginal veins thick, lower marginal vein tomentose. Inflorescence interfoliar becoming infrafoliar in age, 1-I.5 m long, branched to three orders; axes densely silver tomentose when young, densely red-brown tomen- tose at maturity; prophyll boat-shaped,3 5-40 cm long, fully encircling the peduncle at attachment, persistent; peduncular bract one, 70-78 cm long, attached 27-30 cm above attachment of the prophyll, narrowly tubular, persistent and witheringt o a fibrous papyraceous tate;p eduncle elongate, 60-65 x 2.0-3.5 cm wide, laterally compressede, lliptical in cross section; rachilla 16-30 x 0.4-0.5 cm wide, irregularly angled in cross-section, densely tomentose, triads in shallow pits, three to eight triads ranked linear-distichous, rachilla with 40˚-60˚ twists at intermittent intervals, with three to five twists per rachilla. Flowers in triads for entire length ofthe rachilla; staminate flowers bullet-shaped in bud, 6-7 mm long, symmetrical, white; sepals triangular, 3 mm long, margins smooth; petals eiongare, 6 mm long, 2-3 mm wide, apically pointed, thick, apically valvate; stamens 20-35; filaments thino 3-4 mm long; anthers linear, 4 mm long, dorsifixed, versatile; pistillode elongate, 4-5 mm long, flask-shaped. Pollen elliptical in polar view, long axis ca. 36 pm, short axis ca. 15 pm, monosulcate, exine tectate, finely reticulate. Fruit irregularly ovoid, tapered toward the apex, 18-25 x 8-14 mm wide, orange-red at maturity, stigmatic remains apical on a beaked cone; epicarp smooth, drying moderately granular; mesocarp 2-3 mm thick, fibrous; endocarp longitudinally ridged, four-angled in cross section, apex with a moderate beaked extension, surface with numerous irregular shallow channels; seed similarly shaped as endocarp; hilum longitudinal; endosperm homogeneous; embryo basal. Eophyll bifid. (D. Fuller, A New Species of Balaka from Fiji. 1999)A

Materials Examined

  • FIJI. Vanua Levu, above Nakorutari Village, below ridge above Matani Creek alone Raciba Road, McClatchey and Fuller 1095/185, 1099/189, L3 May 1995 (FTG, SUVA). (D. Fuller, A New Species of Balaka from Fiji. 1999)A

Bibliography

A. D. Fuller, A New Species of Balaka from Fiji. 1999
B. World Checklist of Arecaceae