Caia (plant)
This article is about a genus of extinct plants. For other uses, see Caia (disambiguation).
| Caia Temporal range: Late Silurian | |
|---|---|
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Polysporangiophytes |
| Phylum: | †Horneophyta |
| Class: | †Horneophytopsida |
| Order: | †Horneophytales |
| Family: | †Horneophytaceae |
| Genus: | †Caia Fanning et al. (1990)[1] |
| Species | |
|
†C. langii Fanning et al. (1990)[1] | |
Caia is a genus of small fossil plants of Late Silurian age (around 430 to 420 million years ago). The diagnostic characters are naked parallel-sided axes branching isotomously, terminating in vertically elongate sporangia (spore-forming organs) which bear spinous emergences particularly at the distal ends. Spores are trilete and retusoid.[1] The only known species is from Hereford, England.
Cladistic analysis suggests that the genus may belong to the Horneophytopsida, a class of the polysporangiophytes, as it lacks vascular tissue and has branched stems bearing sporangia.[2] For the cladogram, see the Horneophytopsida article.
References
- 1 2 3 Fanning, U.; Edwards, D. & Richardson, J.B. (1990), "Further evidence for diversity in late Silurian land vegetation", Journal of the Geological Society, 147 (4): 725–728, doi:10.1144/gsjgs.147.4.0725
- ↑ Kenrick, Paul & Crane, Peter R. (1997), The Origin and Early Diversification of Land Plants: A Cladistic Study, Washington, D.C.: Smithsonian Institution Press, ISBN 978-1-56098-730-7
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