Caia Temporal range:
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Scientific classification
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Kingdom: | Plantae |
Clade: | Streptophyta |
Clade: | Embryophytes |
Clade: | Polysporangiophytes |
Class: | † Horneophytopsida (?) |
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.