Caia (plant)

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This article is about a genus of extinct plants. For other uses, see Caia (disambiguation).
Temporal range: Late Silurian
Scientific classification e
Kingdom: Plantae
Clade: Polysporangiophytes
Division: Horneophyta
Class: Horneophytopsida
Order: Horneophytales
Family: Horneophytaceae
Genus: Caia
Fanning et al. (1990)[1]

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.


  1. ^ a b c 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 
  2. ^ 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