A class of pteridophyte plants that comprises the horsetails and their extinct relatives.
- ‘In order to build up data infrastructure on the horology of Croatian vascular flora, the present data on the distribution of taxa from the class Sphenopsida were collected from literature and herbarium sources.’
- ‘Equisetum is an ancient genus and comprises the sole surviving representatives of the class Sphenopsida.’
- ‘By the early Mesozoic, these had apparently become extinct, with the rather scanty fossil record of Sphenopsida consisting by then mainly of casts and impressions of stems resembling those of modern Equisetum.’
- ‘These horsetails (Sphenopsida) were arborescent (tree-like) and grew to a height of up to 10 meters.’
- ‘In the past, this group was thought to be ancestral to the Sphenopsida based on their overall structure and organization, but more recent studies show their internal anatomy was more like that of the ferns.’
Modern Latin (plural), from Greek sphēn wedge + opsis appearance.