Abnormal flowers in genus Alpinia

Abstract

There are six types of abnormal flowers in Alpinia described in this paper, namely 2‐stamens, 1.5‐stamen, 1‐stamen, stamen with only one theca, stamen absent and twin‐flower. A different morphological nature of subulate appendage is proposed: it might be the androecial appendage, i.e. appendage of stamen or labellum, but not of staminode. The second type of the abnormal flowers with 1.5‐stamen is regarded as synapomorphy, which is absent in the extant taxa, of the four ginger families, from which were derived the Zingiberaceae and Costaceae with one functional stamen or the Marantaceae and Cannaceae with half stamen. The diversification of the number of stamen in abnormal flowers might be a recurrence of the evolutionary history of stamen in ginger families.

Can the anatomy of abnormal flowers elucidate relationships of the androecial members in the ginger (Zingiberaceae)?

“…Apart from about 2 two-staminate flowers, we observed another two types of abnormal flowers with one fertile stamen in A. intermedia, 1 to 2 flowers with two labella and 1 to 2 flowers with three appendages. Song et al [59] reported that the number of fertile stamen, labellum, appendage, and petal varied in different species of Alpinia genus flowers, and the relative position of fertile stamen, labellum, appendage, and petal was different from normal flowers, rotated from adaxial plane to lateral to abaxial. The continuous variation in the number of stamen may be the reappearance of the evolutionary history of the stamen in the ginger group and even in Zingiberales [59].…”

“…Song et al [59] reported that the number of fertile stamen, labellum, appendage, and petal varied in different species of Alpinia genus flowers, and the relative position of fertile stamen, labellum, appendage, and petal was different from normal flowers, rotated from adaxial plane to lateral to abaxial. The continuous variation in the number of stamen may be the reappearance of the evolutionary history of the stamen in the ginger group and even in Zingiberales [59]. The number of fertile stamen from 2, 1.5, 1, 0.5 to 0, varies continuously to some extent, with intermediate phenotypes of one stamen being the most common.…”

“…Maas [37] found an abnormal flower of Renealmia goyazensis, in which two fully developed anthers replaced the lateral appendages of the labellum. Song et al [59] reported a considerable diversity of developmental transformations in the genus Alpinia. Analyses of the abnormal flowers allow us to deduce robust rules of homeotic transformation that could potentially be generalized across the Zingiberaceae.…”

Can the anatomy of abnormal flowers elucidate relationships of the androecial members in the ginger (Zingiberaceae)?

“…From the above how many staminodes composing labellum largely depends on the staminode development. In the abnormal flowers of Alpinia genus, a tendency for the number of fertile stamens varied from 2, 1 to 0.5 may be the reappearance of the evolutionary history of the stamen in the ginger group and even in Zingiberales (Song et al, 2003). Nevertheless, so far no fossil evidence has indicated that the number of stamen evolves between 6/5 and 1.…”

“…Maas (Maas, 1977) found an abnormal flower of Renealmia goyazensis, in which the lateral appendages of the labellum were replaced by two fully developed anthers. Song (Song et al, 2003) reported a considerable diversity of developmental switches in the genus Alpinia. Analyses of the abnormal flowers allow us to deduce robust rules of homeotic transformation that could potentially be generalized across the Zingiberaceae.…”