Ontogeny of the ovule and seed wing in Catha edulis (Vahl) Endl. (Celastraceae)

The seed wing of Catha edulis (Vahl) Endl. (Celastraceae) has been described as an aril derived from the funiculus. However, the aril-like structure of other Celastraceae has been shown to originate from the micropyle instead of the funiculus. It is therefore of interest whether the seed appendages in Catha are not only functionally but also developmentally different from those in other Celastraceae. To clarify this, the ontogeny of ovule and seed wing in Catha edulis has been studied. It is shown that the wing is a modified caruncula derived from the micropylar region. Seed wings are thus not only interesting in respect to function but may also carry interesting and important evolutionary signals. The evolution of different micropylar appendages within Celastraceae is discussed.