Family Musaceae

Musaceae Juss.

Habit and leaf form. Very large herbs (with pseudo-stems constituted by massive leaf bases); laticiferous. Plants (or at least, the the leaf bases) succulent. Perennial; cormous, or rhizomatous. Pachycaul. Mesophytic. Leaves large to very large; alternate; spiral; flat; petiolate; sheathing. Leaf sheaths with free margins. Leaves simple (but becoming ragged and pseudo-pinnate by tearing between the lateral veins); epulvinate. Lamina entire; lanceolate, or oblong, or ovate (large); pinnately veined (the laterals parallel to one another); without cross-venules (i.e. between the laterals). Vernation convolute.

General anatomy. Plants with laticifers (articulated, with mucilaginous contents). The laticifers in leaves, in stems, in flowers, and in the fruits. Plants with silica bodies (‘trough-shaped’, mostly associated with the vascular bundles). Accumulated starch other than exclusively ‘pteridophyte type’.

Leaf anatomy. Epidermis without silica bodies. Stomata present; tetracytic. Hairs absent.

The mesophyll containing mucilage cells (with raphides); containing calcium oxalate crystals. The mesophyll crystals raphides and solitary-prismatic. Minor leaf veins without phloem transfer cells (1 genus). Vessels absent.

Stem anatomy. Secondary thickening absent. Xylem without vessels. Sieve-tube plastids P-type; type II.

Root anatomy. Root xylem with vessels; vessel end-walls scalariform and simple.

Reproductive type, pollination. Plants monoecious, or andromonoecious, or polygamomonoecious (?). Floral nectaries present. Nectar secretion from the gynoecium (via septal nectaries). Pollination entomophilous, ornithophilous, and cheiropterophilous.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’. The ultimate inflorescence unit cymose. Inflorescences axillary; erect or drooping, thyrses of few flowered cymes; spatheate. Flowers bracteate; medium-sized to large; very irregular; zygomorphic; cyclic; pentacyclic. Perigone tube absent.

Perianth petaline, or of ‘tepals’; 6; joined (five members united, the median inner member posterior and free); rather theoretically 2 whorled (the three outer members and two of the inner members represented by teeth or lobes on a perianth tube, the split coinciding with the inner adaxial, free member); rather theoretically isomerous; petaloid. Corolla (if the perianth is interpreted as such) partially gamopetalous (five members joined, one free). The joined petals anterior (the posterior member free). Corolla more or less bilabiate.

Androecium 5, or 6. Androecial members free of the perianth; free of one another; at least theoretically, 2 whorled. Androecium exclusively of fertile stamens, or including staminodes. Staminodes when present, 1 (the sixth member, opposite the free perianth member, often staminodal or absent). Stamens 5, or 6; diplostemonous; alterniperianthial. Anthers adnate; dehiscing via longitudinal slits; introrse; tetrasporangiate; appendaged (by prolongaton of the connective), or unappendaged. The endothecial thickenings spiral. Microsporogenesis successive. Pollen grains nonaperturate; 2-celled.

Gynoecium 3 carpelled. The pistil 3 celled. Gynoecium syncarpous; synstylovarious, or eu-syncarpous; inferior. Ovary 3 locular. The ‘odd’ carpel anterior. Gynoecium stylate. Styles 1; attenuate from the ovary; apical. Stigmas wet type; papillate; Group III type. Placentation axile. Ovules 10–50 per locule (‘many’); arillate (aril rudimentary), or non-arillate; anatropous; bitegmic; crassinucellate. Embryo-sac development Polygonum-type. Polar nuclei fusing simultaneously with the male gamete. Antipodal cells formed, or not formed (then the three nuclei degenerating early). Synergids pear-shaped. Endosperm formation nuclear.

Fruit fleshy; indehiscent; a berry; 20–100 seeded (‘many’). Seeds endospermic. Endosperm not oily (starchy and mealy). Perisperm present. Seeds with starch. Cotyledons 1. Embryo straight, or curved. Testa without phytomelan; thick, hard.

Seedling. Hypocotyl internode present (fairly pronounced). Mesocotyl absent. Seedling collar conspicuous (in the form of small wings). Cotyledon hyperphyll compact; non-assimilatory. Coleoptile present. Seedling cataphylls present. First leaf dorsiventral. Primary root ephemeral.

Physiology, biochemistry. Not cyanogenic. Alkaloids present (indole), or absent. Proanthocyanidins present; cyanidin, or cyanidin and delphinidin. Flavonols present, or absent; when detected, kaempferol and quercetin (traces). Ellagic acid absent. Saponins/sapogenins absent (?). C3. C3 physiology recorded directly in Musa. Anatomy non-C4 type (Musa).

Geography, cytology. Tropical. Tropical Asia, Africa, Madagascar and Australia. X = 9–11, 16, 17.

Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Zingiberiflorae; Zingiberales. APG 3 core angiosperms; Superorder Lilianae; commelinid Monocot; Order Zingiberales.

Species 42. Genera 3; Ensete, Musa, Musella.

Economic uses, etc. In addition to banana and plantain products (including alcohol, meal), Musa species and varieties are important sources of fibre (abaca cloth, Manila hemp).

Illustrations.
• Technical details: Musa.