Musa X sapientum
If assigning cultivated plants to groups in a valid system is difficult then in the case of food plants grown and improved since time immemorial this is doubly so.
Bananas are robust herbaceous plants with a ‘trunk’ composed of closed leaf sheaths. Up the middle grows a stem with symmetricalcovered with variegated bracts. To date some 80 species of banana have been recorded, distributed in the tropics and subtropics of the Old World. The well-known fruits are many-seeded berries; cultivated varieties, however, are often seedless (sterile) and may be propagated only by vegetative means.
When mature, the plants (even small species) attain dimensions that allow them only to be grown in a greenhouse.
Musa x sapientum, also known as M. paradisiaca sapientum, is probably derived from the crossing of Musa acuminata and M. balbisiana. Likewise derived from M. acuminata in all probability are a number of cultivars sometimes listed under the name M. cavendishii, grown chiefly in the Canary Islands.
Though interested persons will probably only find some of the cultivated banana plants in the botanical garden it is also possible to grow the true species, of which the most suitable would be Musa lasiocarpa from China, only 60 cm (2 ft) high, with the leaf blade making up half of this length. In this species the bracts are yellow, the fruit inedible and dry. Also comparatively small are M. nana (2 m [6 ft]) from China, M. sanguinea (1.5 m [5 ft]) from Assam and M. uranoscopus (2.5 m [8 ft]) from Vietnam.
All banana plants should be grown in open ground or large containers of nourishing compost such as John Innes potting compost No. 3. Feed, chiefly organic fertilizers, should be applied liberally during the growing period. Propagation is not difficult; usually only by division, but botanical species also by means of seed. Germination is unreliable and slow if old seed is used.