Cross section in a leaf of Typhonodorum lindleyanum.

Typhonodorum lindleyanum, common name water banana, is a perennial, rhizomatous plant in Araceae family. It produces a stout, banana-like, pseudo stem. Leaves are sub-triangular to sagittate with parallel veins. It is native to Madagascar, Comoros, Zanzibar, and Mauritius, in Indian ocean.
Water banana is a semi – aquatic plant that grows in swampy areas, in tropical and warm temperate regions. All parts of the plant contain calcium oxalate crystals.

Micrographs below illustrate paraffin cross sections 8 μm thick stained with astra blue – basic fuchsin. The upper micrograph shows a part of the section with the two epidermis and the aerenchyma.

Below: higher magnification of the section. Between the epidermis (epid) most of the mesophyll is aerenchyma. The blue arrow indicates a raphide. On the right of this a vascular bundle. St : stomata.

Characteristics of a hydrophyte: aerenchyma in the mesophyll and thin cuticle for epidermis of both leaf faces.