Inflorescence and flower development in the Hedychieae (Zingiberaceae): Hedychium

Abstract

Flower organogenesis in Hedychium gardnerianum and Hedychium coronarium begins with the sequential formation of the sepals on a rounded–triangular apex. Growth in three regions of the apex, inside the sepals, produces three common petal – inner androecial primordia. Intercalary growth below and between these primordia produces a floral cup, the site of gynoecial formation. The common primordia separate to form petals and inner androecial members. After separation, the anterior inner androecial members fuse to form the labellum. The posterior member forms the polleniferous stamen. Up to this point in development, the flowers of H. coronarium are slightly ahead of those of H. gardnerianum. However, in H. gardnerianum, initiation of the two thecae of the stamen occurs immediately following the separation of the common primordia, while thecae formation in H. coronarium is slightly delayed. These results show that the relative timing of developmental events can vary even over a short developmental period. Formation of the outer androecium takes place at the apices of a triangle formed by the inner androecial members. The anterior outer androecial member aborts soon after formation, whereas the posterior outer androecial members form the two petaloid staminodes that are found on the lateral sides of the labellum in the mature flower. Key words: flower development, flower structure, inflorescence, stamen, Zingiberaceae, Hedychium.

Isolation and Characterization of Three MADS-box Genes from Alpinia hainanensis (Zingiberaceae)

“…Liao et al (2006) supposed the labellum represents the five members of the androecium based on the studies of floral vasculature. The floral development studies reported by Kirchoff (1997Kirchoff ( , 1998 and Song et al (2007) supported the interpretation that the labellum is derived from the congenial fusion of two inner staminodes, and the abaxial outer androecial member contributes only initially to the formation of the labellum.…”

“…1). In spite of quite a few different opinions presented in the past about the nature of labellum based on the morphological and anatomical evidence (Rao 1963;Burtt 1972), the recent evidence on floral organ development supported the notion that the labellum was derived from the congenial fusion of the inner staminodes (Kirchoff 1997(Kirchoff , 1998Song et al 2007). …”

Describing terminologies and discussing records: More discoveries of facultative vivipary in the genus Hedychium J.Koenig (Zingiberaceae) from Northeast India

“…The plant habit ranges from terrestrial to epiphytic as well as lithophytic and each plant has a perennial rhizome which bears new ramets annually. Each ramet gives rise to a terminal inflorescence (known as thyrse) which consists of primary inflorescence bracts that hold flowers in cincinni (Kirchoff 1997). Two main types of inflorescence bracts are identified in Hedychium - imbricate (where bracts are broad and overlapping, hiding the rachis) and folded (where bracts are narrow and fold partially or completely to enclose the flowers, leaving rachis visible, Holttum 1950).…”

Flower and inflorescence development in Salicornia (Chenopodiaceae)

“…However, a correlation between flower position in inflorescence and orientation of its symmetry plane is documented in some angiosperms. In several members of Zingiberales that bear thyrses with lateral cincinni, flowers of successive orders in a cincinnus change their symmetry plane orientation between median and transversal, so that symmetry planes of all flowers are parallel to each other (KUNZE 1985;KIRCHOFF 1997KIRCHOFF , 1998KIRCHOFF , 2000. Interestingly, due to this kind of flower arrangement and symmetry, the only stamen of each flower is in the position closest to the main axis of the inflorescence (e.g., Hedychium: KIRCHOFF 1997, 2000.…”