A THEORY ON THE EVOLUTION OF THE EXINE IN ORCHIDACEAE |
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| Authors: | Pamela Burns-Balogh |
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| Affiliation: | Department of Botany, Smithsonian Institution, NHB 166, Washington, D.C., 20650 |
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| Abstract: | The development of secondarily derived features in orchid pollen precludes the possibility of applying evolutionary trends hypothesized for dicot pollen to orchid pollen and perhaps even monocot pollen. There are three lines of pollen wall development, all secondarily derived from a possible tectate-perforate ancestral type, i.e., tectate-imperforate with incipient columellae (Cypripedioideae), intectate lacking a foot layer (Orchidoideae), and tectate-imperforate with globular masses of sporopollenin (Vandoid Epidendroideae). |
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