Florissantia (plant)

Fossils of Florissantia have been found in Early Eocene to Middle Oligocene localities, including North American fossil beds in Alaska, British Columbia, Colorado, Montana, Oregon, Utah, Washington, Wyoming. Additionally, two occurrences have been reported from southern and eastern Asia in Rajasthan, India and coastal Russian far east. The type species F. speirii is known from a number of formations in the west, with the type locality being the Florissant Formation of Colorado. The formation is composed of successive lake deposits resulting from a volcanic debris flow damming a valley. When the species was described, the Florissant Formation was considered to be Miocene in age, based on the flora and fauna preserved. Successive research and fossil descriptions moved the age older and by 1985 the formation had been reassigned to an Oligocene age. Further refinement of the formation's age using radiometric dating of sanidine crystals has resulted in an age of placing the formation in the Priabonian stage of the Late Eocene. A tentative report of the species from the Katalla Formation, Alaska was made by Jack Wolfe (1977) based on a single specimen. F. quilchenensis has been recovered from four locations in the Okanagan highlands, the Falklands and McAbee sites near Cache Creek, British Columbia, the Coldwater Beds Quilchena site near Quilchena, British Columbia and the Klondike Mountain Formation in Republic, Washington, northern Ferry County, Washington. The youngest F. quilchenensis occurrence is from the early Oligocene Gumboot Mountain Flora of southwestern Washington. Additionally Florissantia sp. fossils have also been reported from Okanagan highlands sites in the Allenby Formation near Princeton, the Horsefly Shales near Horsefly, and the Driftwood Shales near Smithers, British Columbia, without indication of species affinity. The youngest occurrences of F. ashwillii are confined to the Summer Spring shales locality around Grey Butte and thought to correlate with Early Oligocene strata of the John Day Formation. Peng et al. (2011) reported a slightly older late Eocene or Early Oligocene age which was followed by Archibald and Rasnitsyn (2018) who list the site as likely Priabonian or perhaps Rupelian. The flower reported in 2024 from the Northwestern Indian province of Rajasthan was recovered from the Gurha opencast lignite mine working rocks of the Palana Formation. Based on palynological data the formation has an estimated Early Eocene age, with dating between . The Formation has been interpreted to preserve a region of ponds, flood plains, swamps, and waterways moderated by a warm wet climate. ==History and classification==

Fossils now placed in Florissantia were first reported by Leo Lesquereux (1883) from the Florissant Formation and described as the morning glory family species Porana speirii. Additional fossils were described by Knowlton (1916) as another species, Porana similis as well as a third species, which he placed into the new genus Florissantia as Florissantia physalis. which Manchester (1992) redescribed based on a larger selection of specimens from Republic, and moved the species into Florissantia. The first instance of F. ashwillii was published by Chaney and Sanborn (1933) who included the flowers as in their species Viburnum palmatum. Manchester (1992) described the Florissantia species based on a series of 45 fossils found in north central Oregon and noted that the 1933 flower was not related to the leaf holotype fossil of V. palmatum. The F. ashwillii holotype specimen, UF 11740, was a part of the University of Florida collections at the time of description, with additional fossils examined from the University of California Museum of Paleontology collections. Manchester chose the specific epithet ashwillii as a patronym honoring Melvin S. Ashwill who collected many of the specimens examined. ==Description==

All Florissantia species share a distinct set of physical traits in common. The flowers are radially symmetrical shallowly bell shaped, with large sepals fused up to 50% of their length and born on long pedicels. The sepals display a distinct reticulate venation radiating from the center of each sepal with the crossveins forming rectangular to polygonal meshes of smaller veins. Between five and seven major veins run from the sepal base apically before loping towards the apex and fusing together. Additional large veins run to the point of each sinus, and supporting several secondary veins. The basal calyx is thicker than the sepal tissue and often hairy with the small thick petals forming a corolla around the calyx base. The flowers have an expanded androgynophore from which the ovary arises. A single style extends from the center of the ovary though the surrounding androecium to above the corolla of five stamens. The stamen filaments fork once near the tip, and host ten total anthers with elongated to globose outlines. The pollen grains are slightly flattened spheres, with three to four short colpi apertures on the outer surface Florissantia sp. The Palama fossil is smaller, at across, then the reported sizes of the described species. The lobes are large and distinct, ranging between in length with rounded to pointed lobe tips. The sinuses between the lobes extend at most 25% of the flower depth. As is typical for most Florissantia species, the petals dropped from the calyx before it was fossilized. Due to the smaller size and mix of characters, Ashif Ali and his coauthors did not assign the flower to an existing species. ==Paleoecology==

The structure of Florissantia flowers suggests the genus was pollinated by insects or birds. With the long slender pedicels, the flowers likely hung downwards from the plant in an pendant like manner, with dense hairs along the flower bases acting as nectaries. These are features seen in a number of modern Malvaceae genera. Additionally the stamens and styles are thicker and robust, features often associated with bird and bat pollinators, indicating Florissantia may have been a transitional genus between insect pollination and bat or bird pollination. It is possible the caylxes did not grow to full size until after pollination, with the young flowers being smaller and less showy. It is likely the fruits matured into a samara with the calyx acting as a wing around the fruit. ==References==