Calamus deerratus

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Calamus (KAL-ah-muhs)
deerratus (deh-ehr-RAH-tuhs)
Cd2787689.jpg
Near Limbe, Cameroon. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb.
Scientific Classification
Genus: Calamus (KAL-ah-muhs)
Species:
deerratus (deh-ehr-RAH-tuhs)
Synonyms
None set.
Native Continent
Africa
Africa.gif
Morphology
Habit: Clustering
Leaf type: Pinnate
Culture
Survivability index
Common names
None.

Habitat and Distribution

Africa.
Burkina Faso, Houet, Bobo-Dioulasso, F.Cl. du Kou. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb.
Calamus deërratus is the most widely distributed of the rattans of Africa and is distributed across the humid forest zone of Africa; from the Gambia and Casamance in Senegal, southwards to northern Angola and Zambia and eastwards to southern Sudan and Uganda. Calamus deërratus has a strong preference for swamp and riverine forest, and is rather less common in areas with high rainfall. As such, this species is relatively rare in the Guineo-Congolian forest of Cameroon and Gabon. This species is more common in drier gallery forest found in the transition zones between Sudanian savanna woodland to the north of the Guineo-Congolian forest formation, and Zambezian savanna woodland to the south. C. deërratus occurs in lowland forest areas in west and central Africa at altitudes <500 m and in the higher altitude regions of east Africa >1500 m. This species is usually found in forest under a canopy, but also occurs in open areas where it often forms dense thickets. (Dranfield J., A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae) in Phytotaxa 51. 2012)/Palmweb.

Description

Clustered, slender to moderate palm climbing to 20 m, often branching sympodially at the base. Stem without sheaths, 1.0-2.8 cm in diameter, with, 1.2-3.5 cm; internodes 8-20 cm long, more commonly 15-20 cm. Leaf-sheaths varied in armature from almost unarmed to densely spiny, with a distinct horizontal, sometimes folded, knee below the petiole; spines dark brown or black, triangular, flattened at base, up to 3 cm long, clusters of upward pointing spines often concentrated around the leaf-sheath mouth to form a conspicuous cleft; mature sheaths with brown or grey indumentum; ocrea to up 12 cm long, usually 8-10 cm, dry, papyraceous, tongue-shaped, often longitudinally splitting and reflexed, becoming unrecognisable, armed on the margins with spines more pale and bristle-like than those on the leaf-sheath, rarely unarmed. Leaves ecirrate, up to 1.75m long, usually 1.2-1.5m; petiole to 20 cm long, rounded abaxially, concave adaxially, ± 5 mm broad, variously armed with large black spines to 3 cm long and small recurved black thorns; rachis triangular in section distally armed as the petiole, spines becoming sparse distally; leaflets up to 30 on each side of the rachis, sub-equidistant to equidistant proximally, grouped in 3s to 6s distally, linear-lanceolate, finely acuminate to apiculate at apex, bluntly compact at the base, up to 35 cm long by 2 cm broad at the widest point, + concolorous with slightly darker green upper surface, leaflet margins, main vein and secondary nerves bristly throughout. Flagellum up to 3.5m long by 4 mm wide at the base, decreasing very gradually above, armed with small recurved thorns. Male and female inflorescences similar, up to 3.5m long, with 1-4 partial inflorescences and a long terminal sterile flagellum; axis and bracts armed throughout with reflexed, solitary or grouped black prickle-like spines; bracts tightly sheathing, up to 70 cm long with an expanded, papyraceous limb ± 5 cm long; partial inflorescences to 40 cm long, with up to 15 or more rachillae on each side, subtended by bracts + 2 cm long (1 cm. exposed), with mouths + 7 mm wide and with a short triangular limb to 4 mm; rachillae up to 7 cm long, arcuate, arranged distichously; bracts distichous, dull brown in colour, ciliate-hairy around the mouth. Male flowers solitary, distichous, with a minute involucre to 1 mm long; calyx 4 mm long, tubular for + 3 mm, with 3 short, triangular, striate lobes; corolla-lobes to 7 mm long × 2 mm wide, fused at the base for + 1 mm, widely diverging at anthesis; stamens to 4 mm long, minutely epipetalous, with filaments up to 3 mm long, anthers + 3 mm. long, medifixed; pollen yellow. Sterile male flower very similar to fertile male but slightly shorter and narrower. Female flower with calyx tubular at first and then splitting as ovary increases in size, lobes + 3 mm long; corolla-lobes + 5 × 2 mm, with 6 minutely epipetalous flattened staminodes; ovary ± 5 mm long by 2.5 mm wide, tipped by 3 stigmas + 1 mm long, markedly recurved at anthesis. Fruit at maturity to 1.5 cm, × 1 cm with a short beak up to 2 mm tipped by remains of the style, with 17-20 vertical rows of scales. Seed flattened laterally, + 9 × 8 × 5 mm, with sarcotesta + 1 mm thick when dry; endosperm homogeneous, embryo basal. Germination adjacent-ligular; eophyll pinnate. (Dranfield J., A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae) in Phytotaxa 51. 2012)/Palmweb. Editing by edric.

Beccari (1908) acknowledged the close relationship of the African species of Calamus he described, and his treatment of the African representatives of this genus, along those of Drude (1895) and de Wildeman (1904), was reasonable given the fragmentary and often rather poor quality material at their disposal. The fact that Calamus in Africa has been the cause of some taxonomic problems has been undoubtedly due to the recognition of poorly defined infraspecific variation. However, from recent examination of herbarium specimens and field observations, it is clear that Calamus in Africa is represented by a single polymorphic species. (Dranfield J., A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae) in Phytotaxa 51. 2012)/Palmweb.

Culture

Cold Hardiness Zone: 10a

Comments and Curiosities

Etymology: From the Latin 'to go astray' - refers to the habit of this species to form expansive clumps.



External Links

References

Phonetic spelling of Latin names by edric.

Special thanks to Geoff Stein, (Palmbob) for his hundreds of photos.

Special thanks to Palmweb.org, Dr. John Dransfield, Dr. Bill Baker & team, for their volumes of information and photos.

Glossary of Palm Terms; Based on the glossary in Dransfield, J., N.W. Uhl, C.B. Asmussen-Lange, W.J. Baker, M.M. Harley & C.E. Lewis. 2008. Genera Palmarum - Evolution and Classification of the Palms. Royal Botanic Gardens, Kew. All images copyright of the artists and photographers (see images for credits).

Dranfield J., A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae) in Phytotaxa 51. 2012


Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.

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