NAME Pluricellaesporites psilatus
AGE Late Cretaceous.   AGE span: 99.6...65.5 mya
K&J CLASSIFICATION (2000) Fungi Imperfecti, Phragmosporae.
FIGURE(S)
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Pl.12fig.5.jpg
FIGURE REFERENCE Clarke RT. 1965. Fungal spores from Vermejo Formation coal beds (Upper Cretaceous) of central Colorado; Mountain Geologist, v. 2, p. 85-93.
SPECIES, AUTHORITY P. psilatus Clarke 1965, p. 90, pl. 1, fig. 3.
LOCATION Canon City coal field, Fremont County, Colorado, USA.
ORIG DESCRIPTION* Fungal spores uniseriate, individuals consist of five to many cells, cells flattened at common boundaries, convex on sides, cell height 6-10 µm, diameter 13-23 µm, shorter at apices, cell wall psilate, 1-1.5 µm thick, septa 2 µm thick, bidentate, opening through each septum 0.5-1 µm diameter, overall dimensions 13-23 x 82-120 µm.
COMMENTS* The specific name psilatus is given in reference to the smooth cell walls of the spore. Some of the specimens assigned to this species are constricted at a septum (pl. 1, figs. 1, 2). The constriction is probably created by the connection of two individuals. Leopold & Pakiser (1964) reported the occurrence of a teliospore of Basidiomycetae from the Upper Cretaceous McShan and Eutaw formations of western Alabama. No description of the spore type is given, but the illustrated specimen (pl. 9, fig. 1) is morphologically similar to the spore described here as P. psilatus.
PUBLICATION REFERENCE Clarke RT. 1965. Fungal spores from Vermejo Formation coal beds (Upper Cretaceous) of central Colorado; Mountain Geologist, v. 2, p. 85-93.
K&J REMARKS The holotype is closed at the upper (distal) end (bottom in pl. 1, fig. 3 of Clarke). The opposite end of the grain is hidden by a piece of opaque woody material. Under oil immersion, it appeared that this covered end is not rounded, but terminates with a flat surface.

In order to definitely resolve this critical detail, Kalgutkar and Jansonius (2000) examined the type under a confocal laser microscope. This resulted in the clear observation of a flat proximal hilum, as well as of a small septum, apparently fallen inwards from the hilum, which shows a central pore surrounded by a circular thickening.

Clarke (pl. 1, fig. 1-2) also assigned to this species two catenate spores, each of five cells, mutually linked at a deeply incised septum, their opposite free ends being flat and porate/hilate. This form is not conspecific, or even congeneric, with P. psilatus, but now would be assigned to Diporicellaesporites.
TYPE
ALL NAMES (Including synonyms) Pluricellaesporites psilatus
SERIAL NUMBER 1408
PUBLIC COMMENTS
 *For source, see Publication Reference.