Yunia
| Yunia | |
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| Genus: | Yunia
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Yunia is a genus of extinct vascular plants from the Early Devonian (the Pragian stage, around 410 million years ago). The leafless plant consisted of spiny stems which branched dichotomously in a cruciate arrangement. Each stem contained vascular tissue with one or two strands of protoxylem. The spore-forming organs (sporangia) were elongated. The spores had a relatively smooth sculptural pattern and were trilete (i.e. each spore has three lines on it resulting from its formation in a tetrahedral set of four spores).[1]
In 2004, Crane et al. published a simplified cladogram for the polysporangiophytes in which Yunia is basal to the lycophytes (clubmosses and relatives).[2] It had previously been placed in the 'trimerophytes' (a group now thought to be paraphyletic) which were considered to have given rise to all the other vascular plants except the lycophytes.[3]
References
- ^ Taylor, T.N.; Taylor, E.L.; Krings, M. (2009), Paleobotany The Biology and Evolution of Fossil Plants (2nd ed.), Amsterdam; Boston: Academic Press, ISBN 978-0-12-373972-8
{{citation}}: Unknown parameter|lastauthoramp=ignored (|name-list-style=suggested) (help), p. 262 - ^ Crane, P.R.; Herendeen, P.; Friis, E.M. (2004), "Fossils and plant phylogeny", American Journal of Botany, 91: 1683–99, doi:10.3732/ajb.91.10.1683, retrieved 2011-01-27
{{citation}}: Unknown parameter|lastauthoramp=ignored (|name-list-style=suggested) (help) - ^ Taylor, Taylor & Krings 2009, p. 259ff.