Divisestylus gen. nov. (aff. Iteaceae), a fossil saxifrage from the Late Cretaceous of New Jersey, USA

• DOI: 10.3732/ajb.90.9.1373
• Publication Date: 2008-02-29T22:42:44Z
• Authors: Elizabeth J. Hermsen; María A. Gandolfo; Kevin C. Nixon; William L. Crepet
• Keywords: Saxifragaceae; Calyx; Perianth; Sepal; Affinities; Whorl (mollusc); Synapomorphy

Fossilized flowers and fruits from the Upper Cretaceous (Turonian, ca. 90 million years [my] before present) Raritan Formation of New Jersey are described as new genus Divisestylus with two species, D. brevistamineus longistamineus . The fossils fusainized three‐dimensionally preserved. Morphological characteristics suggest affinities extant Saxifragaceae Iteaceae, closely related families in Saxifragales. Similarities include a pentamerous perianth, calyx fused below into hypanthium free sepal lobes above, haplostemonous androecium stamens situated opposite lobes, inferior ovary, bicarpellate gynoecium, numerous ovules on axile placentas, conspicuous intrastaminal nectary ring, capsulate fruit opening apically. unique fusion carpels stigmas but styles free, indicates closer whereas other characters, such basifixed anthers , tricolpate striate pollen grains, anomocytic stomata, indicate to Saxifragaceae. Cladistic analyses utilizing molecular data previously published analysis morphological well alone demonstrate share more recent common ancestor Iteaceae than Saxifragaceae, thereby making oldest known clear Iteaceae.