Allenby Formation Research Articles

The first Odonata from the early Eocene Allenby Formation of the Okanagan Highlands, British Columbia, Canada (Anisoptera, Aeshnidae and cf. Cephalozygoptera, Dysagrionidae)

Abstract Fossil insects have been collected and described from the early Eocene Allenby Formation of southern British Columbia, Canada for over a century, but these have never included Odonata. We describe the first members of that order from the formation: Allenbya holmesae, new genus and species, most likely belonging to the Dysagrionidae (suborder Cephalozygoptera), and a torn, folded, and incomplete wing assigned to the Aeshnidae (suborder Anisoptera) that cannot be identified below family level. In other regional deposits of the early Eocene Okanagan Highlands series of lacustrine shales, the Dysagrionidae is by far the most common odonate family, followed by the Aeshnidae.

Redescription of ‘Amyzon’ brevipinne and remarks on North American Eocene catostomids (Cypriniformes: Catostomidae)

The Eocene catostomid fish (Cypriniformes: Catostomidae) from the Allenby Formation, British Columbia, Canada, is reviewed and revised based on recently collected specimens. The fish was originally recognized as a catostomid by Cope in 1893 and described as Amyzon brevipinne. Wilson comprehensively redescribed the species in 1977 based on a large collection. More specimens collected recently brought to light the need for a systematic revision of this species, different from all known Amyzon species in having a narrow frontal bone with elongated orbital notch, shallow and slender infraorbital series, broad opercle, and short and slender rib 4. It differs from the type species Amyzon mentale in having a shorter posteroventral process of the dentary and fewer dorsal fin rays. Given the differences from all known Eocene catostomid species, Amyzon brevipinne is herein assigned to a new genus as Wilsonium brevipinne. Phylogenetically, this species is resolved as the most basal taxon of Catostomidae. The small-sized fluvial specimens of Wilsonium brevipinne represent the first recognized dwarf catostomid species in the fossil record (maximum standard length ∼ 84 mm). It is also worth noting that Wilsonium gen. nov. differs from all known catostomids in the elongated orbital notch, shallow and slender infraorbital series and non-robust rib 4. These features are seen in some loaches and gyrinchelids. http://zoobank.org/urn:lsid:zoobank.org:pub:A185883A-68FC-4A7F-A103-889EE22ED134

Early Eocene snakeflies (Raphidioptera) of western North America from the Okanagan Highlands and Green River Formation.

Four new species of Raphidiidae are described from the early Eocene of western North America: Megaraphidia antiquissima sp. nov. from McAbee, M. ootsa sp. nov. from Driftwood Canyon, M. hopkinsi sp. nov. from the Allenby Formation (all from British Columbia, Canada), M. klondika sp. nov. from Republic (Washington, United States of America). Archiinocellia Handlirsch, 1910, Archiinocellia oligoneura Handlirsch, 1910 from Horsefly River (British Columbia, Canada), and A. protomaculata (Engel, 2011), comb. nov., from the Green River Formation (Colorado, United States of America) are redescribed. Archiinocellia is assigned to Raphidiidae, sit. nov. The apparent absence of sclerotized gonocoxites 9 in the Archiinocellia protomaculata male is probably plesiomorphic at the family level. As some modern snakeflies do not require a cold interval to complete their development and Eocene Inocelliidae and Raphidiidae lived in regions of warm winters (especially A. protomaculata), adaptation to cold winters in many modern snakeflies is a post-Eocene phenomenon. Eocene Raphidiidae of Europe (Priabonian) differ greatly from those of North America (Ypresian and Priabonian). This pattern might reflect dispersal in either direction or ranges established prior to continental separation. Eocene Inocelliidae of Europe (Priabonian), however, are more similar to those of North America (Ypresian and Lutetian).

Two new species of fossil Eomerope (Mecoptera: Eomeropidae) from the Ypresian Okanagan Highlands, far-western North America, and Eocene Holarctic dispersal of the genus

AbstractTwo new species of Eocene Eomerope Cockerell (Mecoptera: Eomeropidae) are described from the Ypresian Okanagan Highlands deposits of British Columbia, Canada: Eomerope simpkinsaenew species from the Allenby Formation near the town of Princeton, and Eomerope eonearcticanew species from the McAbee locality near the towns of Cache Creek and Ashcroft. Eomerope eonearctica is very close to the coeval Eomerope asiatica Ponomarenko from Primorskiy Kray in Pacific-coastal Russia, consistent with Eocene intercontinental dispersal, which is well documented in numerous plant and animal taxa.

An Eocene brontothere and tillodonts (Mammalia) from British Columbia, and their paleoenvironments

We describe Eocene fossils of the tillodont Trogosus from the Allenby Formation in Princeton, British Columbia (B.C.), as well as teeth of Brontotheriina from the lower Australian Creek Formation near Quesnel, B.C. These fossils represent the only occurrence of Tillodontia and Brontotheriidae in B.C. Further, the presence of the largest species of Trogosus — T. latidens — as well as a smaller species identified only as Trogosus sp. supports a late early – early middle Eocene (Bridgerian) age for the Vermilion Bluffs Shale of the Allenby Formation. Based on their morphology and large size, the teeth referred here to Brontotheriina represent one of the larger, more derived brontothere genera, and suggest a Uintan–Chadronian (middle–late Eocene) age range for the lower Australian Creek Formation that is consistent with radiometric ages of underlying volcanic rocks. Paleobotanical data from sediments correlative to those that produced these Eocene mammal fossils suggest they inhabited forested landscapes interspersed with swamps and open water environments, under mild and wet temperate climates (mean annual temperature (MAT) ∼10–16 °C; cold month mean temperature (CMMT) −4–4 °C; mean annual precipitation (MAP) >100 cm/year). These mixed conifer–broadleaf forests included tree genera typical of modern eastern North American forests (e.g., Tsuga, Acer, Fagus, and Sassafras), together with genera today restricted to east Asia (e.g., Metasequoia, Cercidiphyllum, Dipteronia, and Pterocarya). The paleobotanical evidence is consistent with the hypothesized habitats of both tillodonts and brontotheres.

The Eocene Thomas Ranch flora, Allenby Formation, Princeton, British Columbia, Canada

A flora from Thomas Ranch near Princeton, British Columbia, Canada, is assessed for biodiversity and paleoclimate. This latest Early to early Middle Eocene flora occurs in the Allenby Formation. Seventy-six megafossil morphotypes have been recognized, representing at least 62 species, with 29 identified to genus or species. Common taxa include Ginkgo L., Metasequoia Miki, Sequoia Endl., Abies Mill., Pinus L., Pseudolarix Gordon, Acer L., Alnus Mill., Betula L., Fagus L., Sassafras J Presl, Macginitiea Wolfe & Wehr, Prunus L., and Ulmus L. More than 70 pollen and spore types are recognized, 32 of which are assignable to family or genus. The microflora is dominated by conifers (85%–97% abundance), with Betulaceae accounting for most of the angiosperms. The Climate Leaf Analysis Multivariate Program (CLAMP) calculates a mean annual temperature (MAT) of 9.0 ± 1.7 °C and bioclimatic analysis (BA) calculates a MAT of 12.8 ± 2.5 °C. Coldest month mean temperature (CMMT) was >0 °C. Mean annual precipitation (MAP) was >70 cm/year but is estimated with high uncertainty. Both the CLAMP and BA estimates are at the low end of the MAT range previously published for other Okanagan Highland localities, indicating a temperate climate consistent with a mixed conifer–deciduous forest.

Characterization of the stem anatomy of the Eocene fern Dennstaedtiopsis aerenchymata (Dennstaedtiaceae) by use of confocal laser scanning microscopy

Permineralization provides the most faithful known mode of three-dimensional preservation of the morphology and cellular anatomy of fossil plants. Standard optical microscopic documentation of such structures can provide only an approximation of their true three-dimensional form and is incapable of revealing fine-structural (<300 nm) details, deficiencies that can be addressed by the use of confocal laser scanning microscopy (CLSM). To demonstrate the usefulness of CLSM in such studies, we compare confocal laser scanning micrographs and optical photomicrographs of the permineralized tissues of rhizomes and petioles of the Eocene fern Dennstaedtiopsis aerenchymata preserved in cherts of the Clarno Formation of Oregon, USA, and the Allenby Formation (Princeton chert) of British Columbia, Canada. The laser-induced fluorescence detected by CLSM produces crisp high-resolution images of the three-dimensionally permineralized tissues of Dennstaedtiopsis aerenchymata. Tissues analyzed include the epidermis and epidermal hairs, cortex, aerenchyma, endodermis, vascular tissue, and pith-for each of which, CLSM yields results superior to those of standard optical microscopy. CLSM and previous Raman spectroscopic analyses of the same specimens provide evidence consistent with original biochemistry. Use of CLSM to characterize the morphology and cellular anatomy of permineralized fossil plants can provide accurate data in two and three dimensions at high spatial resolution, information that can be critically important to taxonomic, taphonomic, and developmental interpretations. Results presented here from this first detailed CLSM-based study of permineralized plant axes indicate that this nonintrusive, nondestructive technique should be widely applicable in paleobotany.

Cyclic sedimentation in the Eocene Allenby Formation of south-central British Columbia and the origin of the Princeton Chert fossil beds

Extensive deposits of Eocene conglomerate, sandstone, shale, and sub-bituminous coal occur within a half-graben at Princeton, British Columbia. These strata comprise ∼2000 m of fluvial sediment interbedded with tephra and volcanic flows. Near the southeast margin of the basin, ∼200 m of rhythmically bedded strata are exposed along the Similkameen River. Cyclic deposition resulted from repeated episodes of hydrologic and topographic change related to seismic activity along the Boundary Fault on the east flank of the Princeton Basin, where Allenby Formation sediments are juxtaposed against metamorphic and metavolcanic rocks of the Upper Triassic Nicola Group. Interbedded carbonaceous shale and tuffaceous sandstone record influxes of distal lahar deposits into a lowland swamp. Coal–breccia transitions originated when debris flows along the scarp carried volcanic debris into adjacent wetlands. Coal–chert rhythmites are inferred to be evidence of hydrologic changes associated with floodplain tilt events that caused lowland to repeatedly alternate between a stagnant pond (“fen”) and a stream-fed lake. During fen stages, peat was silicified in situ from percolation of groundwater carrying silica dissolved from underlying tuffaceous beds. Episodic influxes of stream flow reduced dissolved silica concentrations and caused increases in dissolved oxygen levels. These geochemical changes caused organic matter that accumulated during these conditions of open water circulation to remain unsilicified and susceptible to partial maceration. Diagenesis eventually converted these deposits to alternating beds of sub-bituminous coal intercalated with chert horizons.

Characterization of permineralized kerogen from an Eocene fossil fern

The processes of organic maturation that occur during the permineralization of fossils and the detailed chemistry of the resulting products are incompletely understood. Primary among such processes is the geochemical alteration of biological matter to produce kerogen, such as that which comprises the cell walls of the fossils studied here: essentially unmetamorphosed, Eocene plant axes (specimens of the fossil fern Dennstaedtiopsis aerenchymata cellularly permineralized in cherts of the Clarno Formation of Oregon and the Allenby Formation of British Columbia). The composition and molecular structure of the kerogen that comprises the cell walls of such axes were analyzed using ultraviolet Raman spectroscopy (UV–Raman), solid state 13C nuclear magnetic resonance spectroscopy ( 13C NMR) and pyrolysis–gas chromatography–mass spectrometry (py–GC–MS). Cellularly well-preserved fern axes from both geologic units exhibit similar overall molecular structure, being composed primarily of networks of aromatic rings and polyene chains that, unlike more mature kerogens, lack large polycyclic aromatic hydrocarbon (PAH) constituents. The cell walls of the Allenby Formation specimens are, however, less altered than those of the Clarno chert, exhibiting more prevalent oxygen-containing and alkyl functional groups and comprising a greater fraction of rock mass. The study represents the first demonstration of the effectiveness (and limitations) of the combined use of UV–Raman, 13C NMR and py–GC–MS for the analysis of the kerogenous cell walls of chert-permineralized vascular plants.

Regional and local vegetation community dynamics of the Eocene Okanagan Highlands (British Columbia – Washington State) from palynology

Palynofloras from the middle Early to early Middle Eocene Okanagan Highlands (northern Washington State and southern British Columbia) are used to reconstruct vegetation across a broad upland Eocene landscape. In this preliminary report, forest floristic composition is reconstructed using palynological analysis of sediments from Republic, Washington; localities of the Allenby Formation in the Princeton region (Hospital Hill, One Mile Creek and Summers Creek Road), Hat Creek, McAbee, Falkland, Horsefly, and Driftwood Canyon, British Columbia. Wind-dispersed taxa were dominant in all samples, consistent with floras preserved in lacustrine and paludal depositional environments. Pseudolarix was dominant in five of the floras, but Abies (Falkland) or Ulmus (Republic Corner Lot site) were dominant in individual samples for some floras. Betulaceae were dominant for McAbee (Alnus) and Allenby Formation (Betula), matching megafloral data for these sites. Some taxa common to most sites suggest cool conditions (e.g., Abies, other Pinaceae; Alnus, other Betulaceae). However, all floras contained a substantive broad-leaved deciduous element (e.g., Fagaceae, Juglandaceae) and conifers (e.g., Metasequoia) indicative of mesothermal conditions. Palms were only abundant in the Hat Creek coal flora, with very low counts recorded for the Falkland, McAbee, and Allenby Formation sites, suggesting that they were rare in much of the landscape and likely restricted to specialized habitats. Thermophilic (principally mesothermal) taxa, including palms (five sites) and "taxodiaceous" conifers, may have occurred at their climatic limits. The limiting factor controlling the regional distribution of thermophilic flora, which include primarily wetlands taxa, may be either climatic or edaphic.

Vegetative Growth ofDecodon allenbyensis(Lythraceae) from the Middle Eocene Princeton Chert with Anatomical Comparisons toDecodon verticillatus

Large numbers of roots and stems of aquatic Lythraceae have been found in association with fruits and seeds of Decodon allenbyensis Cevallos‐Ferriz et Stockey in the Princeton chert, British Columbia, Canada. The permineralized fossils come from layer 43 in the chert, part of the Middle Eocene, Allenby Formation. Vegetative remains were studied using the cellulose acetate peel technique in an attempt to reconstruct the whole plant of D. allenbyensis. Reconstruction is based on close anatomical comparisons of tissues in the fossil organs to those of extant Decodon verticillatus (L.) Ell. and on attachment of organs and tissue systems. A detailed description of both root and stem wood anatomy is provided for the fossil species. Stem anatomy is revised for extant D. verticillatus, and detailed root anatomy is described for the first time using paraffin sectioning techniques and scanning electron microscopy. Fossil roots and stems show diffuse porous wood with vessels that are solitary or in radial multiples of two to five with numerous tyloses. Heterocellular rays vary from one to at least five cells wide. Secondary phloem with clusters of thick‐walled fibers is preserved in some axes. Most roots and some stems show distinctive concentric layers of thin‐walled lacunate phellem, characteristic of submerged aquatics. This tissue has been described in extant Decodon J.F. Gmelin and other Lythraceae. Anatomy of D. allenbyensis indicates that these plants were growing under submerged conditions with stable water levels at the edge of a quiet body of fresh water.

Permineralized fruits of Diplopanax (Cornaceae, Mastixioideae) from the middle Eocene Princeton chert of British Columbia

Over 80 specimens of a permineralized fruit referable to the Cornaceae (Mastixioideae) have been recovered from the middle Eocene Princeton chert (Allenby Formation) of British Columbia, Canada. Specimens were studied using a modified cellulose acetate peel technique using hydrofluoric acid. Diplopanax eydei Stockey, LePage et Pigg sp. nov. has fruits with endocarps up to 11 mm long and 10 mm in diameter that have a smooth stone surface, a single locule that is U-shaped in cross section, and a germination valve that extends nearly the full length of the fruit. An epicarp (exocarp + mesocarp) composed of thin-walled parenchymatous cells, 1.2–1.5 mm thick, is preserved on one specimen. Remnants of an apical disc with possible perianth scars are seen in three specimens. The endocarp is composed of interlocking fibers with scattered resin ducts and vascular tissue that parallels the edges of the valve. Seed integuments consist of a single external layer of large cells with brown contents and an inner zone of two to four thin-walled cells of smaller diameter lacking contents. Numerous septate fungal hyphae are usually present in the integumentary layers. These fruits represent the first reported fossils of the genus Diplopanax Handel-Mazzetti, and the northernmost known mastixioids in North America. The fruits are compared to those of other living and fossil mastixioids including Mastixicarpum Chandler and add to our knowledge of the diversity and distribution of the North American mastixioids during the Tertiary.

Pinus Pollen Cones from the Middle Eocene Princeton Chert (Allenby Formation) of British Columbia, Canada

Anatomically preserved pollen cones are described from the Middle Eocene Princeton chert of British Columbia, Canada. Cones are ellipsoidal; range from 2.8 to 6.9 mm in length, 1.6 to 3.5 mm in diameter; and are often subtended by scale leaves. Cone axes contain longitudinally oriented, cortical resin canals and 14-18 vascular bundles. Microsporophylls are helically arranged, each bearing two abaxial pollen sacs, many containing pollen grains. Grains are bisaccate and monosulcate, ranging from 50 to 70 μm in length and 27 to 43 μm in width. Proximally, the corpus is rugulate with a tectate-alveolate infrastructure. Sacci have a well-defined endoreticulum and an external ornamentation that is psilate to scabrate. Variations in cone size, cone anatomy, and pollen morphology indicate that several developmental stages are preserved. The large number of cones present in the chert, especially those representing short-lived ontogenetic stages, and the preservational quality of the cones support depositional interpretations for a rapid burial and preservation. These factors also indicate that the pollen cone-producing plants occupied a marginal position in proximity to the lacustrine environment. Four species of Pinus, based on woody twigs, dwarf shoots, leaves, and ovulate cones, are presently known from the Princeton chert. The association of these pollen cones with Pinus similkameenensis leaves and Pinus arnoldii ovulate cones indicates possible taxonomic affinities among these species. The Princeton chert specimens are the oldest Pinus pollen cones to be described and are the first in the genus for which fossil pollen ultrastructure has been described.

Silicified monocotyledons from the Middle Eocene Princeton chert (Allenby Formation) of British Columbia, Canada

The Middle Eocene Princeton chert flora contains the most diverse collection of silicified monocotyledons recovered from the early Tertiary of western North America. Palm vegetative organs are the most common elements and are represented by five stems up to 9 cm wide with attached petiole bases and roots, plus numerous additional isolated petioles, midribs and laminae. Comparisons with extant palms reveal that fossil stem and leaf anatomy is most similar to two coryphoid genera, Rhapidophyllum and Brahea. However, the fossils differ from these genera in several characters and probably represent a new coryphoid taxon. Two small herbaceous monocot stems, one with attached roots, the other with attached roots and remnants of sheathing leaves, each show a pith surrounded by a vascular cylinder composed of several cycles of bundles. The two stems differ in bundle morphology, vessel characters and root anatomy, thus allowing their recognition as distinct types. In addition, a small petiole, Heleophyton helobieoides Erwin and Stockey, shows aerenchymatous ground tissue with numerous minute bundles arranged in five series, a pattern similar to petioles of the extant genus Echinodorus (Alismataceae), but differs in possessing bundle structure like that found in Butomus (Butomaceae). Vascular bundles display a protoxylem lacuna surrounded by a ring of cells with thickened inner tangential walls, 1–3 thin-walled metaxylem elements and a relatively large problem strand. Presence of these structural features suggests Heleophyton grew either submerged or was emergent. Heleophyton also provides further support for the interpretation that the Princeton chert locality represents an ancient lacustrine ecosystem, a site ideal for the study of early Tertiary monocotyledons.

Fruits and Seeds from the Princeton Chert (Middle Eocene) of British Columbia: Rosaceae (Prunoideae)

Three anatomically preserved endocarps, each with one enclosed seed, are described from the Princeton chert (Middle Eocene) Allenby Formation of British Columbia, Canada. Fruits are ovoid, unicarpellate, single-seeded drupes. Endocarps are sclerotic, with one or two ridges on the dorsal side, and a distinct ventral suture that is partially open toward the fruit apex where an obturator is present. Cells along the ventral suture are oriented parallel to the surface of the suture and have thin secondary walls and dark contents. Seeds are anatropous, bitegmic, and ventrally attached to the carpel, with a ventral raphe and a dorsal vascular plexus. The outer integument in two seeds is composed of a single layer with alternating sclereids and thin-walled cells, while in the third seed only sclereids are present. The inner integument consists of a single layer of rectangular, thin-walled cells, but the inner integument becomes multilayered in the micropylar region and along the vascular plexus. These three endoc...

Sapindaceous flowers from the Middle Eocene Princeton chert (Allenby Formation) of British Columbia, Canada

Seventeen small, staminate flowers, 3.0–4.5 mm long × 1.0–1.5 mm wide, representing two developmental stages of the same type of flower have been recovered from the Middle Eocene Princeton chert locality of British Columbia. Some specimens are immature buds with overlapping perianth parts enclosing the stamens; others represent mature flowers with an open perianth. Flowers are pedicellate with a small flat receptacle bearing a perianth of at least three sepals and up to four petals. Five specimens show a three- to four-lobed rudimentary pistil surrounded by an intrastaminal nectary disk. The 10 stamens are included or barely exserted with nonconnate filaments, 1.2–2.0 mm long, attached by a slender connective to large dithecal anthers up to about 0.9 mm long that open by longitudinal slits. The anther wall is represented by a palisadelike endothecium composed of cells that are thick-walled and radially elongated relative to the long axis of the anther. Abundant in situ pollen is semitectate–columellate, tricolporate, subprolate to prolate, and prominently striated with equatorially bridged colpi. This fossil combines flower and pollen characteristics similar to those of the Sapindaceae, resembling most closely the tribe Dodonaeeae. Key words: Sapindales, Dodonaeeae, Tertiary, permineralization, flowers, pollen.

Permineralized fruits and seeds from the Princeton chert (Middle Eocene) of British Columbia: Vitaceae

Four permineralized vitaceous seeds are described from the Middle Eocene Princeton chert, Allenby Formation, British Columbia. Three distinct types of ruminate perchalazal seeds are recognized, one is described as a new species Ampelocissus similkameenensis Cevallos-Ferriz et Stockey sp.nov., while the remaining seeds are referred to as type 1 and type 2 seeds. Five integumentary zones are recognized in each seed: zone 1 is an outer zone of thin-walled rectangular to polyhedral cells; zone 2 is a zone of thick-walled sclereids; zone 3 is a zone of cells with spiral thickenings; zone 4 is a zone of rectangular thin-walled cells (when preserved); and zone 5 is a zone of tangentially elongated thin-walled cells with dark contents. The chalaza in seeds of A. similkameenensis and the type 1 seed has three distinct zones, while in the type 2 seed it contains cells similar to integumentary zone 2. These Princeton seeds illustrate that structural features of Eocene Vitaceae include characters unlike those of extant taxa. This information contributes to our knowledge of anatomical structure within the group as a whole and underscores the need for review of both fossil and extant Vitaceae. Paucity of vitaceous seeds in the Princeton chert compared to the large number of preserved aquatic and semiaquatic remains suggests that they represent plants that grew in a nearby environment. Abrasion of the integument suggests that like extant seeds, they may have been dropped after passing through the gut of a bird.

Permineralized monocotyledons from the Middle Eocene Princeton chert (Allenby Formation) of British Columbia: Alismataceae

One small monocotyledon petiole, 1.8 × 1.5 mm wide, has been recovered from the Princeton chert in the Middle Eocene Allenby Formation, British Columbia. The petiole, rectangular in transverse outline, shows approximately 36 circular to oval-shaped vascular bundles within aerenchymatous ground tissue that includes tannin cells. The epidermis is underlain by a discontinuous hypodermis of thick-walled, pitted cells. Vascular bundles are in five series: (I) a median U-shaped arc of 11 – 13 bundles; (II) an abaxial arc of 6 bundles located below the main arc; (III) two short abaxial arcs of 3 bundles each; (IV) 2 bundles just below the abaxial surface; and (V) an adaxial series of 7 bundles that show an inverse orientation to those bundles in series I–IV. Larger bundles are collateral, with a protoxylem lacuna encircled by a ring of 9 – 14 thin-walled parenchyma cells, a relatively well-developed phloem strand, and one to three thin-walled metaxylem elements. Based on bundle arrangement, orientation, and morphology, the fossil petiole most closely resembles those of the Butomaceae and Alismataceae. This new species, Heleophyton helobiaeoides Erwin and Stockey gen. et sp.nov., in the Princeton chert flora, documents the presence of the Alismataceae in the Middle Eocene of western North America and provides further evidence that the locality represents an ancient aquatic ecosystem.

Permineralized Fruits and Seeds from the Princeton Chert (Middle Eocene) of British Columbia: Nymphaeaceae

Nymphaeaceous seeds and their probable fruit remains are described from the Middle Eocene Allenby Formation of Princeton. British Columbia. These seeds are subspheroidal to ovoid, anatropous, exarillate, and operculate. Two openings in the operculum represent the position of hilum and micropyle. Cells of the operculum are radially elongate with straight walls and can be distinguished from cells of the palisade-like outer integumentary layer that have sinuous radial walls. Surface views of cells of the outer integument show sinuous walls with four to 10 undulations per cell. The inner zone of the outer integument is composed of one to two rows of tangentially elongated thin-walled parenchymatous cells. The inner integument is composed of one to two rows of tangentially elongated, thin-walled cells. Two seeds have been found with preserved perisperm. A single vascular strand runs from hilum to chalaza, and a raphal ridge is present. Comparisons to seeds of both extant and fossil Nymphaeales show that these seeds should be included in the family Nymphaeaceae. Allenbya collinsonae Cevallos-Ferriz et Stockey gen. et sp. nov. shows closest similarities to the fossil genera Dusembaya and Palaeonymphaea and may be related to the extant genus Victoria. The description of this new taxon adds to our knowledge of the four lines of nymphaeaceous seed morphology and their evolution. Evolutionary trends within the Nymphaeales include: the establishment of tubercles or small protuberances in the outer integument in one line, and the change in position of the hilum from the operculum to the seed body and development of a broad integumentary zone beneath the palisade in a second line. These fossils show that the family Nymphaeaceae was more diverse in the past and add to our knowledge of the aquatic elements in the Princeton flora.

PERMINERALIZED FRUITS AND SEEDS FROM THE PRINCETON CHERT (MIDDLE EOCENE) OF BRITISH COLUMBIA: ARACEAE

Some of the most conspicuous fruit and seed remains from the Middle Eocene Princeton chert locality (Allenby Formation) are assignable to the Araceae. Several thousand campylotropous, reniform, spiny seeds 2.5–3.2 mm long x 1.8–2.3 mm wide have been found dispersed in the chert. Two fruits, each with a single locule and at least eight ovules, show three distinct wall layers and appear to have been fleshy. The two layers of seed integument have pitted isodiametric sclereids aligned in radial rows, the outermost being thinner walled. Spines are borne in three rows on the dorsal seed surface while the ventral side is flattened. Idioblasts that probably contained raphides are present in the outer integument. Nucellar tissue is attached to the integument for most of its length and is well‐preserved in some seeds near the chalaza and in the large conical shaped area beneath the micropyle. Endosperm cells with dark contents and curved, linear, monocotyledonous embryos are present in some seeds. Sections of seeds of living araceous taxa of the subfamilies Monsteroideae (Epipremnum, Rhodospatha) and Lasioideae (Urospatha, Cyrtosperma) were made for comparison. The fossil seeds represent a new taxon most closely related to Cyrtosperma, Keratosperma allenbyensis Cevallos‐Ferriz et Stockey gen. et sp. nov., Family: Araceae, Subfamily: Lasioideae, Tribe: Lasieae. The Princeton remains are the oldest described seeds of this tribe known to date and add to our knowledge of the subtropical elements of the Princeton flora.