Abstract
The root structure ofPodostemum subulatum is investigated and compared with that ofZeylanidium olivaceum. Podostemum has thread- or ribbon-like roots. The root tip consists of an inner apical meristem and a single-layered root cap. From roots arise numerous shoots of endogeneous origin. Their vascular bundle isab initio connected with the root bundle.
By the simple (reduced) apical zonation, the roots ofPodostemum subulatum appear more advanced than the crustose roots ofZeylanidium olivaceum, which bear an ordinary (though asymmetrical) root cap. With regard to the endogeneous root-borne shoots, however,Zeylanidium appears more advanced because of the shoot dimorphism. The floriferous shoots have a short axis that grows plagiotropously above the crust surface, whereas the axes of the vegetative shoots are extremely short and remain, together with the apical meristem, within the crust. Only the leaves protrude from the crust surface.
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Jäger-Zürn, I. Developmental Morphology of Roots and root-borne shoots ofPodostemum subulatum as compared withZeylanidium olivaceum (Podostemaceae—Podostemoideae) Part VII of the series ‘Morphology of Podostemaceae’. Pl Syst Evol 220, 55–67 (2000). https://doi.org/10.1007/BF00985370
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DOI: https://doi.org/10.1007/BF00985370