The pollen ultrastructure of Williamsoniella coronata Thomas (Bennettitales) from the Bajocian of Yorkshire
Document Type
Article
Publication Date
11-1-2009
Description
The exine ultrastructure of Williamsoniella coronata Thomas from the Bajocian of Yorkshire (United Kingdom) was investigated with light, scanning electron, and transmission electron microscopy. The pollen averages 16.5 μm alongitsshort axisand24.5μmalongitslongaxis andismonosulcate, and thenonapertural sculpturingisdistinctly verrucate. The pollen wallishomogeneous, and the sulcus membraneiscomposedofthin exine withscattered small granules. The pollen grains differ in exine sculpturing and pollen wall ultrastructure from pollen grains of the bennettitalean taxa Cycadeoidea dacotensis (MacBride) Ward and Leguminanthus siliquosis (Leuthardt) Kraeusel. They are similar todispersed pollen grainsof Granamonocolpites luisae Herbst from the Triassic Chinle Formation of the United States, supporting the bennettitalean affinity of these dispersed pollen grains. The Bennettitales are palynologically characterized by monosulcate "boat-shaped" pollen with a homogeneous or granular pollen wall ultrastructure.
Citation Information
Zavialova, Natalia; Van konijnenburg-Van Cittert, Johanna; and Zavada, Michael. 2009. The pollen ultrastructure of Williamsoniella coronata Thomas (Bennettitales) from the Bajocian of Yorkshire. International Journal of Plant Sciences. Vol.170(9). 1195-1200. https://doi.org/10.1086/605873 ISSN: 1058-5893