Laccosperma acutiflorum (Becc.) J.Dransf., Kew Bull. 37: 456 (1982)

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Content

Distribution

Laccosperma acutiflorum is distributed from Sierra Leone to Cameroon, southwards to Gabon and Democratic Republic of Congo. (Sunderland, T.C.H. 2012: A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae). – Phytotaxa 51: 1-76)A

Biology And Ecology

  • Laccosperma acutiflorum is a light demanding species commonly found in gap vegetation and in open areas. This species often occurs in seasonally-inundated and swamp forest, although it is also found in drier, exposed sites. L. acutiflorum responds well to selective logging and will colonise recently disturbed soil particularly on skid trails and roadsides. (Sunderland, T.C.H. 2012: A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae). – Phytotaxa 51: 1-76)A

Conservation

  • Least concern (LC). (Sunderland, T.C.H. 2012: A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae). – Phytotaxa 51: 1-76)A

Etymology

  • (Latin) refers to acuminate calyx lobes. (Sunderland, T.C.H. 2012: A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae). – Phytotaxa 51: 1-76)A

Description

  • Clustered robust to massive palm climbing to 70 m, more commonly to 30-50 m. Stems without sheaths 3.5-4.5 cm, with 4.5-5 cm; internodes up to 40 cm long, more commonly 18-25 cm. Leaf sheath light green-yellowish, conspicuously striate, moderately to sparsely armed with angular, black-tipped, spreading or upward pointing, spines, mature sheaths becoming somewhat bare, with only vestigial remains of spines, covered with sparse black-brown indumentum; ocrea 12-20 cm long (although up to 40 cm long on juvenile sheaths only), broadly sheathing and tapering to form a rounded lobe, dry, sometimes splitting longitudinally, light grey-brown without, deep crimson brown within, armed as the sheath although spines often concentrated in central region of ocrea. Leaves up to 3.5 m long; petiole 6-10 cm long × 2-3 cm. wide, much longer on juvenile sheaths (up to 45 cm) light green to dull yellow, with sparse light brown indumentum beneath, abaxially rounded, adaxially flattened or slightly concave, armed along the margins with inequidistant black-tipped, bulbous-based spines 0.8-1 cm long, angular, spreading in many directions; rachis yellow-green, up to 1.8-2.5m long, shaped as the petiole proximally, becoming trapezoid to triangular in cross section distally, armed as the petiole, although spines becoming more sparse distally, underside of rachis with sparse light brown indumentum; cirrus often bright yellow, 1.2-1.8 m long, scarsely armed, ± triangular in cross section; leaflets up to 50 on each side, held horizontally or arching from the rachis, rarely strictly pendulous with a single-fold, equidistant and sub-opposite proximally, alternate distally, linear lanceolate, bluntly acuminate to apiculate at the apex (often breaking off), 30-40 cm long, more commonly 18-30 cm, 3.0-4.5 cm broad at the widest point, rarely up to 6 cm wide, discolorous with dark green upper lamina, light green lower surface, leaflet margin armed with sub-equidistant robust, short, forward-facing black-tipped spines, up to 2mm long, 1-2- or rarely 3-5 costulate, armed as the margin although spines on primary veins rather longer; acanthophylls bright yellow, 4-4.5 cm. long, 0.5 cm. broad, bulbous at base. Inflorescences, numbering 6-12 produced simultaneously in the distal 1.5-2.5 m portion of stem; peduncle 15-20 cm long; prophyll up to 20 cm; rachis branches up to 50 cm long, perpendicular to the main axis, rachis bracts 3-3.5 cm long, decreasing distally, tapering to form an elongate triangular lobe adaxially, closely adpressed to the bract above, upper half dry, grey, longitudinally splitting, at first, lower half fleshy, bright yellow-green, then, as fruits develop, becoming dry throughout; rachillae 20-30 cm long, pendulous, densely covered with yellow-green imbricate bracts 4-5 mm long, with a wide opening and 1 mm long apiculum. Flowers at anthesis 1-1.2 cm × 3 mm; calyx 5-6 mm long, excluding 1.5-2.0 mm stalk, indistinctly striate, cream, tubular in the basal 2-3 mm with 3 broadly triangular to acuminate lobes 3.0-3.5 mm × 2.0-2.5 mm; corolla tubular in the basal 1.5-2 mm, with 3 valvate lobes, white or pale cream, rarely mottled brown/tan, ca.9 mm × 2 mm with broadly acuminate tip; stamen filaments dark brown, 4-5 mm × 1 mm, united into a 1-1.5 mm-long basal tube; anthers 3 mm × 1 mm, ovary ca.1 mm in diameter, stigma up to 6 mm. Fruit at maturity ovoid, 1- (sometimes 2) seeded, 1.8-2 cm × 1.3-1.5 mm wide, with 17-20 vertical rows of scales. Seed smooth, ovoid, with lightly scalloped depression on one side 1.0-1.2 cm long × 0.8-1.2 mm wide × 0.5-0.8 mm deep. (Sunderland, T.C.H. 2012: A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae). – Phytotaxa 51: 1-76)A

Materials Examined

  • SIERRA LEONE: Gledhill 339, Koruboula to Sokwela (09º12N:10º56W) sterile, February 17, 1966 (K!); Jordan 2064, Gola forest (07º45N:10º45W) Fl., May 13, 1955 (K!); GHANA: Chipp 643, Konongo, Ashanti region (06º37N:01º12W) Fr., February 4, 1914 (K!); Enti758, Aiyaola Forest Reserve (06º09N:01º53W) Fl., June 1972 (MO!); Sunderland 2263, Draw River Forest Reserve (05º12N:02º20W) sterile, May 26, 1999 (K!, KUM!); NIGERIA: Morakinyo 1000, Cross River National Park (05º15N:08º42E) Fl. & Fr., August 10, 1993 (K!); CAMEROON: Dransfield 7001, Mungo River Crossing (04º08N:09º31E) Fl., June 27, 1991 (K!); Dusen 292, Ndian (05º00N:09º00E) Fl. 1892 (FI!); Preuss 1232, Victoria to Bimbia (03º59N:09º13E) Fl., April 10, 1894 (FI!); Sunderland 1707, Southern Bakundu Forest Reserve (04º46N:09º29E) Fr., November 8, 1995 (K!, SCA!, WAG!); Sunderland 1714, Kumba to Mamfe road (05º02N:09º24E) Fr., November 30, 1995 (K!, SCA!, BH!); Sunderland 1723, 30km north of Mamfe (05º58N:09º20E) Fr., December 2, 1995 (K!, SCA!, BR!); Sunderland 1764, 15km from Kribi on Campo road (02º34N:09º50E) Fr., December 1, 1996 (K!, YA!, MO!); Sunderland 1855, 10km from Kribi at Grande Batanga (02º09N:09º48E) Fl., August 30, 1997 (K!, YA!, NY!, BR!); Sunderland 1882, Mbakwa-Supe flyover, 20km south of Nguti (05º02N:09º24E) Fr., November 26, 1997 (K!, YA!, BH!, MO!, WAG!); Sunderland 1926, Campo Ma'an Faunal Reserve (02º10N:09º54E) Fl., October 10, 1998 (K!, YA!, WAG!); Thomas 9738, Idenau (04º16N:09º01E) Fr., September 10, 1993 (K!, SCA!); van Gemerden 110, River Lobe, near Kribi (02º57N:09º54E) Fr., December 15, 1996 (K!); EQUATORIAL GUINEA: Sunderland1907, Near village of Njakem (01.42N:09.40E) juvenile, March 24, 1998 (K!, YA!, EG!, WAG!); DEMOCRATIC REPUBLIC OF CONGO: de Graer 216, Adjala (02º02S:15º08E) sterile, November 12, 1933 (BR!); Louis 16995, Oriental Province, Lac Yangambi (00º47N:24º26E) Fr., September 1944 (K!); Vanderyst6411, sterile, 1917 (BR!) (Sunderland, T.C.H. 2012: A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae). – Phytotaxa 51: 1-76)A

Bibliography

    A. Sunderland, T.C.H. 2012: A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae). – Phytotaxa 51: 1-76