Laccosperma robustum (Burret) J.Dransf., Kew Bull. 37: 457 (1982)

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Distribution

L. robustum is very common species throughout its range and is distributed from SE Nigeria to the central Congo Basin. (Sunderland, T.C.H. 2012: A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae). – Phytotaxa 51: 1-76)A

Discussion

  • L. robustum was first described by Burret (1942) from specimens collected by Mildbraed in Moloundou, Cameroon, early in the 20th century. Although the material that Burret cites was destroyed in the allied bombing of Germany in World War II, his description clearly matches this taxon. In this respect a neotype is assigned for this species, (Harris 5706) collected in the same area, although across the border in what is now the Central African Republic. (Sunderland, T.C.H. 2012: A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae). – Phytotaxa 51: 1-76)A

Biology And Ecology

  • This species is commonly encountered in forest gaps and regrowth vegetation and responds well to selective-logging activities. It is encountered on both terra firma and seasonally-inundated forest. (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) "robust" or "stout". (Sunderland, T.C.H. 2012: A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae). – Phytotaxa 51: 1-76)A

Description

  • Clustered robust palm climbing to 30-45 m. Stems without sheaths 30-50 mm in diameter, with 45-60 mm; internodes 35-50 cm long, although more commonly 18-25 cm. Leaf sheath moderately to profusely armed with black-tipped finely triangular, upward pointing or spreading spines; sheaths on upper portion of stem more sparsely armed; juvenile sheaths particularly profusely armed; dense brown-black indumentum present on mature sheaths, more sparse on juvenile sheaths; ocrea 20-30 cm long, dry, gradually tapering at the apex, reflexed, tattering longitudinally and disintegrating, dark tan mid-brown without, crimson-brown within, armed as the sheath although spines often concentrated at the apex, particularly on juvenile sheaths. Leaves up to 3.5m long; petiole 5-12 cm long, 1.5-2.5 cm. wide, mid to dark green with scattered brown-black indumentum, particularly on upper surface, abaxially rounded, adaxially lightly to moderately concave proximally becoming flattened in cross section distally, armed along the margins with inequidistant black-tipped angular spines up to 1.4 cm long, spreading in many directions; rachis 1.5-2 m long, shaped as the petiole, becoming more trapezoid in cross section then triangular in cross-section distally, armed as the petiole proximally, spines becoming more sparse distally, with sparse brown indumentum present below; cirrus up to 1.5-2 m. long, triangular in cross section, only very sparsely armed with reflexed bulbous-based black-tipped spines, sparse brown indumentum below; leaflets always composed of a single-fold, 45-65 on each side of the rachis, equidistant, opposite to sub-opposite proximally, inequidistant, alternate distally, papyraceous, conspicuously pendulous, finely linear-lanceolate, base abruptly contracted, apex broadly to finely acuminate, often breaking off, 30-45 cm long (commonly up to 60 cm) 1.2-2.8 cm broad at the widest point, ± concolorous, glaucous blue-green, margins armed with inequidistant exceptionally fine, 5-8mm-long, forward facing curved or angular black-tipped spines; 1 costulate midrib armed as the margins although spines much longer.; acanthophylls 4.5-5 cm long. Inflorescences, numbering 6-12 produced simultaneously in the distal 1.5-2.2m portion of stem; peduncle 12-20 cm long; prophyll ± 15 cm long; rachis branches up to 50 cm long, perpendicular to the main axis; rachis bracts glabrous, 1.5-1.8 cm long, decreasing distally, dry throughout, covered in dense brown-black indumentum, tapering to form a truncate triangular lobe abaxially, closely adpressed to the bract above; rachillae 18-25 cm long, pendulous, rachillae bracts campanulate-cylindrical, ± 5 mm long, dry throughout, triangular to broadly acuminate adaxially, each with a wide opening and a 1.5 m.-long apiculum. Flowers in dyads, rarely triads, at anthesis ± 1 cm × 2.5-3.0 mm wide; calyx ± 6 mm long, excluding 1-1.5 mm long angular stalk, 2.5-3 mm wide, tubular in the basal 4 mm only, with 3 dark-tan, lightly striate, rounded to triangular, rarely acuminate, apex, 3.5 × 3 mm; corolla, tubular in the basal 2 mm only, with 3 valvate lobes ca.7 × 2 mm, white or cream, with a bluntly acuminate apex; stamen filaments, brown, fleshy, angular, 3 mm × 1 mm broad, united into 1.5 mm-long basal tube; anthers 3 mm × 1 mm broad; ovary ± 1 mm in diameter, stigma up to 5 mm. Fruit at maturity ovoid; 1- (rarely 2-) seeded, 1.2-1.5 cm × 0.8-1.2 cm, with 17-20 vertical rows of scales. Seed smooth, ovoid, with lightly scalloped depression on one side, 0.8-1.3 cm long × 0.6-0.8 cm wide × 0.5 cm thick. (Sunderland, T.C.H. 2012: A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae). – Phytotaxa 51: 1-76)A

Materials Examined

  • NIGERIA: Smith 53, Calabar (04º59N:08º20E) Fl., June, 1931 (K!); CAMEROON: Bililong & Bullock 348, Campo Faunal Reserve (02º14N:09º54E) seedling, s.d. (K!); Bos4799, 20km from Kribi (03º00N:10º03E) Fl., June 10, 1969 (K!, MO!, WAG!, YA!, BR!); Bos 5160, 20km from Kribi, (03º00N:10º03E) Fr., August 7, 1969 (K!, WAG!, BR!, YA!); Dransfield 7006, Limbe to Kumba road, Mile 40 (05º02N:09º24E) sterile, June 28, 1991 (K!, SCA!); Gentry & Thomas 52727, Korup National Park (05º00N:08º30E) sterile, November 12, 1985 (K!, MO!); Gentry & Thomas 52766, Korup National Park (05º00N:08º30E) sterile, November 12, 1985 (MO!); Letouzey 7368, Nr Benga on Douala to Yaounde rd, Fl., July 7, 1966 (YA!); Letouzey 8479, Nr Kamelon, 10km SE Sangmelima (02º55N:11º58E) Fr., November 24, 1966 (YA!); Lowe 3442, Edea-Kribi rd nr Elogbatindi (03º27N:10º11E) sterile, January 22, 1978 (K!, YA!); Njingum 1, Nkakanzock, near Edea (03º49N:10º14E) sterile, May 15, 1999 (K!); Njingum 3, NW Province, Bagoran, sterile, June 1, 1999 (K!); Njingum 5, Akom II (02º47N:10º34E) sterile, July 1, 1999 (K!); Njingum9, Nguti (05º02N:09º24E) sterile, August 5, 1999 (K!); Sunderland 2305, Korup National Park, Chimpanzee Camp (05º02N:08º48E) sterile, February 18, 2000 (K!, SCA!); Sunderland 2306, Korup National Park, Chimpanzee Camp (05º02N:08º48E) sterile, February 18, 2000 (K!, SCA!); Sunderland 1645, Mokoko River Forest Reserve (04º29N:09º00E) sterile, May 1, 1994 (K!, SCA!); Sunderland 1708, Southern Bakundu Forest Reserve (04º46N:09º29E) Fr., November 8, 1995 (K!, SCA!, BR!); Sunderland 1722, 30km north of Mamfe (05º58N:09º20E) sterile, December 2, 1995 (K!, SCA!, BH!); Sunderland 1740, Rumpi Hills Forest Reserve (04º54N:09º20E) sterile, May 19, 1996 (K!, SCA!, WAG!); Sunderland 1747, Rumpi Hills Forest Reserve (04º54N:09º20E) sterile, May 19, 1996 (K!, SCA!, MO!); Sunderland 1757, Limbe --Kumbe road, Mile 40 (04º23N:09º26E) sterile, November 11, 1996 (K!, SCA!, MO!); Sunderland 1928, Campo Ma'an Faunal Reserve (02º10N:09º54E) sterile, October 11, 1998 (K!, YA!); Sunderland 1930, Takamanda Forest Reserve (06º06N:09º47E) sterile, November 9, 1998 (K!, SCA!); Sunderland 1935, Takamanda Forest Reserve (06º06N:09º47E) sterile, November 15, 1998 (K!, SCA!); Sunderland 2058, Takamanda Forest Reserve (06º08N:09º16E) sterile, January 18, 1999 (K!, SCA!); Sunderland 2253, Mokoko River Forest Reserve (04º29N:09º00E) sterile, February 16, 1999 (K!, SCA!); Sunderland 2254, Mokoko River Forest Reserve (04º29N:09º00E) sterile, February 16, 1999 (K!, SCA!); van Gemerden Bi, Kribi to Lolodorf road (03º13N:10º38E) sterile, s.d. (K!); CENTRAL AFRICAN REPUBLIC: Fay 8236, Ndakan (02º21N:16º09E) sterile, February 16, 1988 (MO!); Fay 8254, Ndakan (02º21N:16º09E) sterile, February 20, 1988 (MO!); Harris 5704, Sangha-Mbaere (02º59N:16º13E) Fr., December 16, 1997 (K!); Harris 5706, (ibid.) Fr., December 16, 1997 (K!); Harris 5718, (ibid.) Fr., December 25, 1997 (K!); Harris 5719, (ibid.) Fr., December 25, 1997 (K!); Harris 5720, (ibid.) Fr., December 25, 1997 (K!); EQUATORIAL GUINEA: Sunderland 1791, Bata to Mbini road, 17km from Bata (01º45N:09º43E) Fr., March 11, 1997 (K!, EG!, BH!); Sunderland 1799, 4km north of Ayemeken village (02º10N:10º03E) Fr., March 13, 1997 (K!, EG!, NY!, MO!); Sunderland 1915, 5km from village of Nsork (01º53N:11º06E) Fr., April 2, 1998 (K!, EG!, WAG!); Tessmann 2, sterile, s.d. (FI!); GABON: Wilks 1486, 20km N of Koumameyong (00º22N:11º54E) Fr., April 1, 1987 (MO!); DEMOCRATIC REPUBLIC OF CONGO: Bermejo 19, Equator: zone d'Ikela (00º36S:20º06E) Fr., s.d. (BR!); Breyne 2357, Maluku, Plateau des Bateke (03º52S:15º00E) Fr., June 15, 1975 (MO!, BR!); Dubois 911, Boendu, S of Maringa (00º56N:20º03E) Fr., August 1938 (K!, BR!, MO!); Evrard 4943, Kodoro-Yekokora (01º16N:20º06E) Fr., September 26, 1958 (BR!); Leonard 1671, Popolo (03º06N:20º45E) Fr., August 20, 1955 (BR!); Leonard 3817, Kigulube: Shabunda (02º36S:28º00E) Fr., April 11, 1959 (BR!); Liegeois 89, sterile, July 1943 (BR!); Louis 6445, Yangambi (00º45N:24º26E) Fr., October 27, 1937 (BR!); Louis 16049, River Bokuye (tributary of the Luye), sterile, September 11, 1939 (BR!); Louis 16794, Yangambi (00º45N:24º26E) sterile, November 17, 1943 (BR!); Ndjele 732, 44km from Lubutu (00º42N:26º32E) sterile, June 22, 1981 (BR!); Toussaint 2294, Vallee de la Nkula, Fr., May 7, 1947 (BR!, FHO!); ANGOLA: Gossweiler 7541, Mayombe, Luali (05º00S:12º25E) sterile, 1919 (K!) (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