The embryology of epipogium roseum (Orchidaceae)

Development of pollen and female gametophyte in Epipogium roseum (D. Don)Lindl. has been investigated. The embryo sac conforms to the Apinagia type. The taxonomic position of Epipogium within the family is discussed. © 1981 Springer-Verlag

Pollen-carriers of periplocaceae and their systematic value

Pollen-carriers of 5 taxa of periplocaceae sensu stricto are described. These are ill organised in Cryptolepis and Cryptostegia and well organised in Decalepis and Hemidesmus. The pollen tetrads are free in the former two taxa but organised into massulae in the latter. In their pollen carriers Decalepis and Hemidesmus appear to connect periplocaceae with Secamonoideae of Asclepiadaceae

The embryo sac of Podostemum subulatus (Podostemaceae) - a reinvestigation

The female gametophyte ontogeny in Podostemum subulatus is of the Apinagia type and not the Podostemum type as reported earlier. The independent existence of the Podostemum type in the family is questioned. © 1980 Springer-Verlag

Embryogenesis in sexual and asexual species of Zeuxine (Orchidaceae)

The development of the zygote following sexual union in Zeuxine longilabris exhibits a predetermined polarity and patternized sequence of developmental stages leading to the initiation of cotyledonary and epicotylary activity in adjacent sectors, both being terminal on the embryonal axis. The cotyledonary growth is incipient and the epicotylary sector is distinguishable only by histological distinctivity. The initiation and trend of growth of the asexual embryo totally deviates from that of its sexual counterpart. Although incipient and inconsistent polarity becomes established in the dividing nodular cell system eventually the embryos end up as a spindle-shaped structure of homogeneous cells where not even the initiation of root and shoot polar differentiation is seen either within or without. Under these circumstances the asexual embryos are broadly comparable to the earlier stages in the development of embryoids in free cell cultures. © 1981 Indian Academy of Sciences