Hamawilsonia boglei Benedict, Pigg & DeVore gen. et sp. nov. (Hamamelidaceae) is described from the Late Paleocene Almont flora of central North Dakota. The infructescence is an anatomically preserved spike with up to 20 sessile, robust, cuboidal to ovoid capsules borne on an elongate, thick axis up to 9:2 cm long x 0:5 cm wide. Individual fruits are 10-12 mm across and bilocular, with paired persistent, recurved styles borne on the distal carpel face. One locule is often larger than the other. Anatomically, the fruit wall is composed of a sclerified endocarp and a poorly preserved exocarp. Seeds are elliptical to slightly obovate with a sclerotic seed coat. Hamawilsonia is an extinct Late Paleocene genus with a combination of characters not seen in any extant hamamelid genus. Hamawilsonia is similar to the Asian endemic genus Sinowilsonia in its elongate spikelike infructescence, resembles the witch hazel Hamamelis in fruit and seed morphology, and has seed anatomy that combines features found in several extant genera. Affinities with Sinowilsonia are further supported by the cooccurrence of associated pollen catkins and in situ tricolpate pollen with a distinctive reticulate sculpturing. Like several other Almont taxa (Amersinia, Beringiaphyllum, Davidia, and Palaeocarpinus), Hamawilsonia is a genus with strong North American-Asian affinities.
- Explosive dehiscence
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Plant Science