Jamesonia

• Authority

  Mickel, John T. & Beitel, Joseph M. 1988. Pteridophyte Flora of Oaxaca, Mexico. Mem. New York Bot. Gard. 46: 1-580.

• Family

  Pteridaceae

• Scientific Name

  Jamesonia Hook. & Grev.

• Description

  Genus Description - Terrestrial; rhizome short- to long-creeping, with dark, bristle-like hairs; fronds linear, erect, small to medium-sized, generally indeterminate, the apex slow to fully unroll; stipe short, dark; blade once-pinnate, the pinnae small, mostly round, imbricate, hairy or glandular, at least abaxially, herbaceous to coriaceous, margin generally inrolled; veins free, branching; sporangia along the veins, often obscure due to the dense indument and the curved margin; false indusium present or lacking; spores tetrahedral-globose, lacking perispore but with equatorial flange.

• Discussion

  Type: Jamesonia pulchra Hooker & Greville. Jamesonia has 19 species of tropical America, largely of high elevation, Mexico to Bolivia and southeastern Brazil. It is closely allied to Eriosorus, with which it hybridizes in Central and South America (A. Tryon, 1970). The Oaxaca locality is the northernmost record for the genus. Jamesonia is distinct in the linear, once-pinnate blade that is ± permanently circinate at apex. References: Tryon, A. 1962. A monograph of the fern genus Jamesonia. Contr. Gray Herb. 191: 109-197; Tryon, A. 1970. A monograph of the fern genus Eriosorus. Contr. Gray Herb. 200: 54-174.