Musaceae Juss.

Every, J.L.R. & Baracat, A. (2009). Neotropical Musaceae.

Morphology

Description

Large to giant suckering, glabrous herbs with sympodial rhizomes, short-thick underground stem ( corm ), erect pseudostems formed by overlapping leaf sheaths. Leaves alternate , spirally arranged, simple , with course tubular sheath , petiole long (sometimes absent), margins entire (often split due to wind action), lanceolate or oblong , midrib distinct, venation closely set, parallel with slightly sigmoid lateral veins fusing near margins. Inflorescence terminal , indeterminate, massive, pendent, sometimes erect , extensive thyrse with large distichous or spiraling, purple, spatheaceous, boat-shaped, deciduous bracts, enclosing a cincinnus (a dense monochasial cyme ). Flowers unisexual and monoecious , zygomorphic , rarely bisexual in proximal part of inflorescence ; basal flowers pistillate, apical flowers staminate, tepals 6, petaloid , outer ones and the inner 2 are fused into a 3-5- lobed tube, split on one side, inner tepal free , small, simple , scale-like, directed downwards, subtended by hyaline , recurved bracts; stamens 5 or 6 with one staminodial, alternating with perianth , filaments free from each other and perianth , filiform , anthers basifixed, opening via longitudinal slits; ovary inferior, syncarpous, carpels 3, 3-locular, style 1, filiform , ovules numerous, septal nectaries present. Fruit a baccate , mostly indehiscent , oblong or cylindrical (banana-shaped) leathery, red-yellow, easily split longitudinally. Seeds usually absent in Neotropical plants, c.9mm 5-15 mm in diam. when present, surrounded by a starchy, sweetish pulp derived from placental trichomes.

General Description

Notes on delimitation

• Has been broadly circumscribed in the past to include Strelitzia Aiton, Ravenala Adans., Phenakospermum Endl., Heliconia L. and often also Orchidantha N. E. Br.
• Currently treated as a family containing the genera Musa L. and Ensete Horan. (APG 2, 2003).
• In the pantropical order Zingiberales as part of the bananas alongside the gingers i.e. Cannaceae, Costaceae, Marantaceae and Zingiberaceae.

Number of genera

• One Musa (30-50 species).
• One non-Neotropical Ensete (c.6 species).

General notes

• Musaceae provide bananas Musa ×sapientum L. and plantains Musa ×paradisiacal L.
• Inflorescenceerect and self-pollinated or pollinated by sunbirds in SE Asia (hummingbirds in the Neotropics) or bat-pollinated and functional for only one night.
• Inflorescence represents the aerial stem.

Status

• From multiple origins in SE Asia from where they have been spread by man.
• Cultivated throughout the Neotropics preferring lowland forest.

Distribution

Distribution in the Neotropics

• Often growing in dense stands in humid, lowland forest.
• Frequently cultivated as a food crop.

Diagnostic

Distinguishing characters (always present)

• Large habit.
• Enormous inflorescence and infructescence usually weighed down by flowers or fruit.
• Unisexual flowers - basal flowers female, apical male.
• 6 petaloid tepals.
• Ovary inferior.
• Fruit a banana.

Other important characters

• Massive leaves frequently torn by the wind.
• Purple, boat-shaped, caducous bracts.
• Stamens 5 (-6) the 6th one mostly staminodial.

Key differences from similar families

• Unisexual flowers vs. bisexual in Strelitziaceae and Heliconiaceae.
• Many ovules per locule vs. one ovule per locule in Heliconiaceae.
• Leaves spiral and fruit exarillate vs. leaves distichous and fruit arillate in Strelitziaceae.
• Torn leaves may appear superficially palm-like, however members of Arecaceae have truly pinnate or palmate leaves and a superiorovary.

Literature

Important literature

Andersson, L. 1998. Musaceae. In: K. Kubitzki (Ed.), the families and genera of vascular plants 4:226-30. Springer-Verlag, Berlin.

APG 2. 2003. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants. Botanical Journal of the Linnean Society. 141. pp. 399-436.

Dahlgren, R.M.T., Clifford & H.T., Yeo, P.F. 1985. The Families of the Monocotyledons: Structure, Evolution and Taxonomy. pp 356-358. Springer-Verlag, Berlin, New York and Tokyo.

Kress, W. 1990. The phylogeny and classification of the Zingiberales. Annals of the Missouri Botanical Garden 77:4. pp. 698-721.

Kress, W. J., Prince, L. M., Hahn, W. J. & Zimmer, E. A. 2001. Unravelling the evolutionary radiation of the families of the Zingiberales using morphological and molecular evidence. Systematic Biology 50:6 pp. 926-944.

Maas, P. J. M. & Westra, L. Y. Th. 2005. Neotropical Plant Families. 3rd ed. p. 99. A.R.G. Gantner Verlag K.G., Ruggell.

Seberg,O. 2007. In: V.H. Heywood, R.K. Brummitt, A. Culham & O. Seberg (eds). Flowering plant families of the world, p. 382-3. Kew: Royal Botanic Gardens, Kew.

Stevens, P. F. 2008. Angiosperm Phylogeny Website. Version 9 onwards. http://www.mobot.org/MOBOT/research/APweb/.

Stevenson, D. W. & Stevenson, J. W. 2004. Musaceae. In: Smith, N., Mori, S. A., Henderson, A., Stevenson, D. W. and Heald, S. V. (eds.). Flowering Plants of the Neotropics. pp. 462-3. The New York Botanical Garden, Princeton University Press, Princeton.

Watson, L. and M. J. Dallwitz (1992 onwards). The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 14th December 2000. http://delta-intkey.com

Yatskievych, K. 2001. In: Steyermark, J. A., Berry, P. E., Yatskievych, K. & Holst, B. K. (eds). Flora of the Venezuelan Guayana. Volume. 6 Liliaceae-Myrsinaceae. pp 731-3. Missouri Botanical Garden, St. Louis.

Musaceae, J.M.Lock. Flora of Tropical East Africa. 1993

Morphology General Habit

Giant herbs from a branched or unbranched corm-like rootstock

Morphology Leaves

Leaves arising from the apex of the corm, spirally arranged, very large; leaf-sheaths elongated, densely imbricate and forming a cylindrical pseudostem; lamina oblong, with a strongly channelled midrib and very many pinnately-arranged parallel lateral veins

Morphology Reproductive morphology Inflorescences

Inflorescence terminal on the corm, growing up through the centre of the pseudostem and thus appearing to arise from its apex

Morphology Reproductive morphology Flowers

Flowers unisexual, those on the proximal parts of the inflorescence ?, on the distal ?, borne in condensed groups subtended by spathaceous bracts

Morphology Reproductive morphology Flowers Calyx

Calyx spathaceous, splitting down one side, with ± 3 teeth at the apex

Morphology Reproductive morphology Flowers Corolla

Corolla lobes 3, 2 of them adnate to the calyx-tube, the third separate and directed downwards

Morphology Reproductive morphology Flowers Androecium

Stamens 6, but one usually rudimentary; filaments terete, thin; anthers dithecous with parallel thecae

Morphology Reproductive morphology Flowers Gynoecium

Ovary inferior, 3-locular; placentation axile; ovules many

Morphology Reproductive morphology Fruits

Fruit a large elongated fleshy 3-locular berry containing, in the wild species, numerous very hard subspherical seeds containing a straight embryo and copious endosperm