''Sanmiguelia'' is an extinct plant genus, probably of flowering plants. The genus and the species ''Sanmiguelia lewisii'' were first described in 1956 from the Late Triassic Chinle Formation in Colorado, and later in Lower Jurassic Moenave Formation in Utah. The species has been suggested to be one of the more primitive angiosperm fossils.

Description

Since ''Sanmiguelia'' was first described in 1956, other specimens have been discovered. These suggest that plants were about tall, and consisted of a conical stem with helically arranged leaves. The leaves were broadly elliptical, with a pointed apex and a base that clasped the stem. The stems were woody and contained secondary xylem composed of tracheids. Reproductive organs found in the same beds are believed to have belonged to ''Sanmiguelia''. The pollen-bearing organs consist of an axis with many helically arranged microsporophylls, each with a pair of pollen sacs. The ovule-bearing organs consist of an axis bearing structures interpreted as carpels. Pollination is thought to have been carried out by insects.

Taxonomy

The affinities of ''Sanmiguelia'' have proved controversial. When first described, the leaves of ''Sanmiguelia'' were described as palm-like. Later an affinity with Monocotyledon, monocots, in particular ''Veratrum'', was suggested. Others questioned this interpretation and suggested that ''Sanmiguelia'' was a cycad. When fossil reproductive structures were assigned to ''Sanmiguelia'', it was considered to be a primitive angiosperm that combined features of both monocots and dicots.

References

Prehistoric angiosperm genera Enigmatic angiosperm taxa Triassic plants Jurassic plants {{triassic-plant-stub