Ptilozamites
Ptilozamites is an extinct genus of pteridosperm, known from the Triassic and Early Jurassic of the Northern Hemisphere. It is associated with the pollen organ ''Harrisiothecium.''Taxonomy
The genus was first erected by Alfred Gabriel Nathorst in 1878 for remains found in Scania in southern Sweden. Nathorst did not declare a type species While the species Ptilozamites nilssonii was described in the same paper that named the genus, later authors have treated Ptilozamites heeri as the type genus. Recent authors have suggested that the genus Ctenozamites is a synonym of Ptilozamites. Most authors interpret Ptilozamites as an enigmatic "seed fern", though some authors historically suggested that they were related to cycads.Description
The leaves of Ptilozamites are pinnate. The leaves have an odontopteroid venation, and a thick cuticle. The leaves as a whole are typically elongate, with stomata being present either on both sides or only on the underside of the pinnules, with the stomata being surrounded by a thickened ring of tissue. The leaves of Ptilozamites are often forked, like the leaves of the corystosperm seed fern Dicroidium.Modern authors have suggested that the pollen-producing organ Harrisiothecium is part of the same plant that produced Ptilozamites leaves. This structure is composed of a central axis which bears branches which terminate with capsules composed of two flap-like valves, which bear pollen sacs on their inner surface. This structure bear similarities to Pteruchus, Antevsia, the enigmatic pollen organs Pteroma, ''Pramelreuthia and Townrovia,'' as well as the pollen organs of Bennettitales.''''Ptilozamites was widespread across the Northern Hemisphere during the Late Triassic and Early Jurassic, with remains having been reported from Europe, Greenland and China.