Article

Prunus and Oemleria (Rosaceae) Flowers from the Late Early Eocene Republic Flora of Northeastern Washington State, U.S.A.

International Journal of Plant Sciences (Impact Factor: 1.53). 09/2011; 172:948-958. DOI: 10.1086/660880

ABSTRACT

Two genera of Rosaceae are described from the latest early Eocene Republic flora of northeastern Washington State, United States. Prunus cathybrownae sp. nov. (Rosaceae: subfamily Spiraeoideae, tribe Amygdaleae sensu Potter et al.) is based on eight flowers, including one containing in situ pollen and two immature fruits. Flowers are actinomorphic, perigynous, and pentamerous, with a campanulate hypanthium bearing five sepals. The gynoecium is unicarpellate and consists of a distally flared, bilobed stigma; an elongate style; and an ellipsoid, bilaterally asymmetric ovary. Two whorls of stamens—an inner one in which stamens are reflexed and an outer whorl of extended stamens—are both inserted into the hypanthium. Pollen from the outer whorl is 20 μm in diameter and tricolporate with a striately ornamented exine; clusters of smaller, presumably immature grains 7 μm long and 4 μm wide lacking distinctive ornamentation were recovered from the inner whorl. Immature fruits differ from the flowers in either having a senescent style or lacking one entirely and having fewer remnants of perianth parts and a larger and more symmetrical ovary. A second flower, Oemleria janhartfordae sp. nov. (Rosaceae: subfamily Spiraeoideae, tribe Osmaronieae sensu Potter et al.) is actinomorphic and perigynous and has five free pistils that each resemble the solitary pistil of Prunus. These include a flattened, bilobed stigma and an ellipsoid, bilaterally asymmetric ovary. The fossil has the laterally fixed, elongate style characteristic of the genus. These fossils are the oldest known floral examples of these two genera and demonstrate that both Prunus and Oemleria were present in the latest early Eocene in western North America. The Okanogan Highlands floristic province provides the earliest fossil evidence to date for the first major radiation of the Rosaceae, an important mostly temperate, mostly Northern Hemisphere family.

Download full-text

Full-text

Available from: Kathleen B Pigg
  • Source
    • "ificance of the Turgai Straits in shaping the diversifica - tion and biogeographic history of Prunus in Europe can be evident as suggested by the fossil records of Prunus ( wood and , endocarps ) in Europe – the fossils records were sparse from the late Eocene but became more apparent during the Miocene ( $ 14 Myr ) and Plio - cene , $ 3 Myr ( see Benedict et al . , 2011 ; DeVore and Pigg , 2007 ; Li et al . , 2011 ; Wheeler et al . , 1978 ) . Incidentally , this trend in tem - poral distribution of fossil records might reflect the presence of the Turgai Straits as a dispersal barrier between Europe and eastern Asia between 55 and 35 Myr , but dispersal became possible after the disappearance of the Tur"
    [Show abstract] [Hide abstract]
    ABSTRACT: Most previous molecular phylogenetic studies of Prunus have been conducted primarily with crop species and their close relatives. As the center of crop diversity of the genus is in Eurasia, the geographic origin of Prunus has inevitably been inferred to be Eurasia as well. The lesser-known tropical Prunus species have not been well represented in previous phylogenetic reconstructions; therefore, their effects on inferences about the phylogenetic structure and geographic origin of Prunus are uncertain. In this study, we examined the phylogeny of Prunus, including an expanded sampling of species from tropical regions in Southeast Asia and the Americas, using sequences from four plastid markers and the nuclear ribosomal ITS region. A penalized likelihood method was used to estimate the absolute age of Prunus and the timing of infrageneric cladogenic events. The geographic origin of Prunus and ancestral sites of cladogenesis were inferred using the Bayes-DIVA approach. Our results indicate that the modern genus appeared ∼61 Myr in eastern Asia and that diversification of all major lineages may have been triggered by the global warming period of the early Eocene. In addition, our molecular dating estimates suggest that the crown clade that includes the temperate deciduous crop species is older than the one that includes the tropical evergreen species, while incongruence between plastid and nuclear phylogenies suggests that the latter lineage originated via an ancient hybridization event. The most recent common ancestor (MRCA) of the temperate crop species was a component of the continuous boreotropical forests of the Northern Hemisphere, while the MRCA of the tropical species represented the last remains of the boreotropical elements and subsequently radiated throughout the Old and New World tropics from refugial areas at lower latitudes. Complex biogeographic histories leading to the present global distribution of the genus were driven by several geologic events, climatic oscillations, and independent dispersals across continents via the Bering and the North Atlantic Land Bridges during different geologic time periods.
    Full-text · Article · Jul 2014 · Molecular Phylogenetics and Evolution
  • Source
    • "El estudio de plantas fósiles basado en flores, ha sido recurrente en los últimos años (e.g.,Takahashi et al., 2008a, Takahashi et al., 2008b, Friis et al., 2009, MartínezMillán et al., 2009, Calvillo-Canadell et al., 2010, Schmidt et al., 2010, Benedict et al., 2011, y Schōnenberger et al., 2012), su importancia radica en que constituye una fuente de información taxonómica inagotable, ya que éstas han sido usadas desde ha tiempo como herramientas de identificación y clasificación de las angiospermas (e g. Linneo, 1753; Bemtham y Hooker, 1862-1883). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Simojovel de Allende, Chiapas, Mexico, is one of the amber deposits in the world with exceptionally preserved biological evidence of plants and animals. Within the paleobotanical record of the area members of Anacardiaceae, Leguminosae, Meliaceae and Arecaceae have been reported based on flowers, which are a special case because of its delicate and ephemeral structures, difficult to preserve in the fossil record. In this paper we describe the morphology of two flowers preserved in amber from Chiapas, attributing possible taxonomic affinities. The first one corresponds to a small bisexual, hipogineous, pedicellated, pentameric flower, with differentiated perianth. These characters allow its comparisonm with members of the families Ericaceae, Malvaceae, Rutaceae and Sapindaceae, however, it has higher morphological similarity with Sapindaceae due to the presence of 5 pubescent filament. A second inconspicuous, unisexual flower, with differentiated perianth, 2 ovate sepals and 3 clawed petals is compared with Commelinaceae, Alismataceae, Menispermaceae, and Polygonaceae: The latter ones having greater resemblance to the fossil flower based on the presence of five pubescent stamens. The possible presence of Sapindaceae and Polygonaceae in the past of southern Mexico, supports the idea of the presence of a tropical forest in the Simojovel de Allende at that time, however, the fossil flowers are in need of further comparison with those of extat plants to confirm their taxonomic identification, allowing a better understand of the paleoenvironment as well as of the floristic elements composing the vegetation for 20 m. a.
    Full-text · Article · Aug 2013
  • Source

    Full-text · Article · Jan 2011 · Annals of the Missouri Botanical Garden
Show more