Mixed Handedness and Indentations in Spathes, and Handedness of Cataphylls, of Alocasia brisbanensis (Araceae)

Left- and right-handed and mixed individual spathe imbrications (foldings) and spathes with indentations at the edges of the spathal chamber margins, were recorded for Alocasia brisbanensis. Indentations (either a single pair or a double pair) were also recorded in the spathal limb. In 1996 the numbers were not significantly different from a 1:1 ratio, but in 1997 right-handed spathes of inflorecences were in excess and the numbers were significantly more numerous. The plants with spathal folding abnormalities (mixed folding and/or indentations) had one or more inflorescences affected in the same year, and in one case in both 1996 and 1997. Two plants with abnormalities in 1996 produced only normal inflorescences in 1997. Cataphylls with tips extended into rolled blades also showed left-and right-hand folding. The mechanism underlying handedness in spathes and cataphylls, as well as changes in direction and in some cases changes back to the original direction, needs to be investigated.