A Cytological Study of the <i>Zingiberales</i> with Special Reference to Their Taxonomy

Abstract

1. The chromosome numbers of 64 species have been studied on which 56 are investigated for the first time.2. Morphological, anatomical and cytological findings on the Musaceae in the broad sense are considered from a phylogenetical standpoint and three distinct groups:a) Musa-Ensete, b) Ravenala-Strelitzia-Phenakospermum and c) Holiconia are recognised as suggested by some authors. For these groups sub-familial status is proposed.3. Lowiaceae have been studied for the first time cytologically and their chromosome morphology, distinct from that of any other group of Zingiberales, confirms their claim to familial status.4. Consideration of the conflicting theories proposed to account for the higher chromosome number in genera like Globba, Alpinia, and Phaemeria, etc. leads to rejection of Chakravorti's hypothesis of wholesale fragmentation of chromosomes and the acceptance of the opposed view of Raghavan and Venkatasubban and others.5. Holttum's transference of the genus Zingiber to the tribe Hedychieae has been given cytological support on the following points:a) the basic number in the genus Zingiber correlates with that of Kaempferia.b) the new tribe Alpinieae (which is infact Zingibereae without Zingiber) have consistently 48 chromosomes in their somatic complements.6. It is suggested that the African representatives of Kaempferia should be given the status of genus; Cienkowskya on the following points:a) the difference in floral morphologyb) geographical separateness andc) the difference in the number and morphology of the chromosomes. By comparing the present and past findings, various lines of evolution of the chromosome complements within each group are discussed.7. The basic number 11 is considered to be probably the original one for the Zingiberales as a whole, being present in Ravenala which is the most primitive member in the order. From this secondary basic numbers have arisen through evolution.