Oncocalamus mannii

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Oncocalamus
(on-koh-kahl-AH-muhs)
mannii (mahn'-nee)
Om2788615.jpg
Near Limbe, Cameroon, Africa. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb.
Scientific Classification
Genus: Oncocalamus
(on-koh-kahl-AH-muhs)
Species:
mannii (mahn'-nee)
Synonyms
None set.
Native Continent
Africa
Africa.gif
Morphology
Habit: Clustering
Leaf type: Pinnate
Culture
Survivability index
Common names
None.

Habitat and Distribution

Cameroon, Chad, Congo, Equatorial Guinea, Gabon, Nigeria, Zaire,
Near Limbe, Cameroon, Africa. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb.
O. mannii is restricted from southern Cameroon to Gabon. O. mannii is common in open areas, roadside and forest gaps. This species responds extremely well to selective logging and is a common component of regrowth vegetation.

Description

Clustered slender to moderate palm climbing to 15-30 m. Stems without sheaths 8-16 mm in diameter, with 12-28 mm; internodes 12-18 cm long. Leaf sheath longitudinally striate, dark green, tan, often dull crimson brown on young sheaths, moderately to sparsely armed with brown-black spines, concentrated and persistent on the ocrea, spines often sloughing off elsewhere on sheath to leave conspicuous, raised, circular, blister-like scars; thin, white caducous indumentum present on mature sheaths, particularly dense on young sheaths and juvenile individuals; ocrea ± truncate or saddle-shaped with a 0.5-1.8 cm high rounded lobe opposite the rachis, armed as the leaf sheath, spines concentrated at ocrea margin, extending ± 2 cm. Spear leaf deep orange to bright crimson. Juvenile stems up to 6 m long, with sheaths, <1 cm in diameter, leaves sessile or with a short (1.5 cm) petiole, strongly bifid, eventually becoming pinnate, up to 30 cm long and 4.5-6 cm broad at the widest point and with a 60 cm long cirrus emerging from the centre; elaminate rachis often present at base of stem, up to 2.5m long. Leaves on mature stems sessile, or with a short (<2.5 cm) flattened petiole; rachis 1-1.2 m long, abaxially rounded, adaxially concave, becoming circular in cross section distally, armed as the leaf sheath, spines particularly profusely armed on underside, although often smaller than those on the sheath; cirrus 1-1.5 m long, unarmed; leaflets, 25-35 on each side of the rachis, linear-lanceolate, to mildly sigmoid, broadly attenuate at the base, apex somewhat acuminate, 16-32 cm long, 1.8-2.5 cm broad at the widest point, ± concolorous, dark green, armed along the margins with robust spines particularly at base of leaflet, single-nerved, with 6-7 conspicuous secondary nerves on each side; lowermost leaflets smaller than the rest, held vertical to rachis; acanthophylls up to 1.5 cm long. Inflorescences in successive axils 3-5 m from stem apex; peduncle 8-15 cm long, hemispherical in cross section; prophyll 3-8 cm long; peduncular bracts 2-4, 2.5-4 cm long; rachis up to 0.8-1m long, pendulous; rachis bracts 2.5-4 cm long; rachillae circular in cross section, 15-28 cm long, pendulous, bracts deep-bright crimson prior to anthesis, becoming dry, brown; prophyll subtending flower cluster 3-5 mm, conspicuously striate. Flower cluster with 1-3 central pistallate flowers subtended by 2 lateral cincinni of 1-2 pistillate and 2-3 staminate flowers; staminate flowers 5.5-6.5 mm × 2-3 mm; calyx about 5.0 mm × 5.0-5.5 mm, including 1 mm-long stalk, tubular for ½ to ¾ of its length; corolla about 5 mm long, tubular for the basal ±1 mm, cream/yellow; staminodial tube about 2 mm long; anthers 0.8 mm × 0.3 mm; pistillode 1.5 mm × 0.7 mm, thin, tapering; pistillate flowers similar to the staminate flowers, up to 3-4 mm wide; ovary about 2.5 mm × about 1.5 mm. tipped by 1-1.5 mm long style. Fruit at maturity, globose to sub-globose, 1.8-2.2 cm × 1.6-2 cm, with 15-17 rows of vertical scales. Seed sub-globose 1.2-1.6 cm × 1.5-1.9 cm, with a narrow rounded depression below, covered with regular polygonal depressions, giving a distinctly warty appearance; sarcotesta white, thin (<0.5 mm). (T.C.H Sunderland, A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae) in Phytotaxa 51. 2012)/Palmweb. Editing by edric.

Culture

Comments and Curiosities

Etymology: The specific epithet in honor of Gustav Mann (1836-1916), German botanist and horticulturist.



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).

T.C.H Sunderland, 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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