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Lycopodiaceae are one of three surviving families of lycopsids, a lineage of vascular plants with a fossil history dating to at least the Early Devonian or perhaps the Late Silurian (c. 415 Ma). Many fossils have been linked to crown Lycopodiaceae, but the lack of well-preserved material has hindered definitive recognition of this group in the paleobotanical record. New, exceptionally well-preserved permineralized lycopsid fossils from the Early Cretaceous (125.6 ± 1.0 Ma) of Inner Mongolia, China, were examined in detail using acetate peel and micro-computed tomography techniques. The anatomy of extant Lycopodiaceae was analyzed for comparison using fluorescence microscopy. Phylogenetic relationships of the new fossil to extant Lycopodiaceae were evaluated using parsimony and maximum likelihood analyses. Lycopodicaulis oellgaardii gen. et sp. nov. provides the earliest unequivocal and best-documented evidence of crown Lycopodiaceae and Lycopodioideae, based on anatomically-preserved fossil material. Recognition of Lycopodicaulis in Asia during the Early Cretaceous indicates the presence of crown Lycopodiaceae at this time, and striking similarities of stem anatomy with extant species provide a framework for the understanding of the interaction of branching and vascular anatomy in crown-group lycopsids.

Leaves are the most abundant and visible plant organ, both in the modern world and the fossil record. Identifying foliage to the correct plant family based on leaf architecture is a fundamental botanical skill that is also critical for isolated fossil leaves, which often, especially in the Cenozoic, represent extinct genera and species from extant families. Resources focused on leaf identification are remarkably scarce; however, the situation has improved due to the recent proliferation of digitized herbarium material, live-plant identification applications, and online collections of cleared and fossil leaf images. Nevertheless, the need remains for a specialized image dataset for comparative leaf architecture. We address this gap by assembling an open-access database of 30,252 images of vouchered leaf specimens vetted to family level, primarily of angiosperms, including 26,176 images of cleared and x-rayed leaves representing 354 families and 4,076 of fossil leaves from 48 families. The images maintain original resolution, have user-friendly filenames, and are vetted using APG and modern paleobotanical standards. The cleared and x-rayed leaves include the Jack A. Wolfe and Leo J. Hickey contributions to the National Cleared Leaf Collection and a collection of high-resolution scanned x-ray negatives, housed in the Division of Paleobotany, Department of Paleobiology, Smithsonian National Museum of Natural History, Washington D.C.; and the Daniel I. Axelrod Cleared Leaf Collection, housed at the University of California Museum of Paleontology, Berkeley. The fossil images include a sampling of Late Cretaceous to Eocene paleobotanical sites from the Western Hemisphere held at numerous institutions, especially from Florissant Fossil Beds National Monument (late Eocene, Colorado), as well as several other localities from the Late Cretaceous to Eocene of the Western USA and the early Paleogene of Colombia and southern Argentina. The dataset facilitates new research and education opportunities in paleobotany, comparative leaf architecture, systematics, and machine learning.

PREMISE Seed cones of extant Pinaceae exhibit two mechanisms of seed release. In "flexers" the cone scales remain attached to the central axis, while flexing and separating from each other to release the seeds. In "shedders" scales are shed from the axis, with the seeds either remaining attached to the scale or becoming detached. The early fossil history of Pinaceae from the Jurassic to Early Cretaceous is dominated by flexing seed cones, while the systematic information provided by shedding fossil cones has been overlooked and rarely integrated with data based on compression and permineralized specimens. We describe the earliest and best-documented evidence of a "shedder" seed cone from the Aptian-Albian of Mongolia. METHODS Lignite samples from Tevshiin Govi locality were disaggregated in water, washed, and dried in air. Fossils were compared to material of extant Pinaceae using LM and CT scans. RESULTS Lepidocasus mellonae gen. et sp. nov. is characterized by a seed cone that disarticulated at maturity and shed obovate bract-scale complexes that have a distinctive ribbed surface and an abaxial surface covered with abundant trichomes. The ovuliferous scale has ca. 30-40 resin canals, but only scarce xylem near the attachment to the cone axis. Resin vesicles are present in the seed integument. Phylogenetic analysis places Lepidocasus as sister to extant Cedrus within the abietoid grade. CONCLUSIONS The exquisite preservation of the trichomes in L. mellonae raises questions about their potential ecological function in the cones of fossil and living Pinaceae. Lepidocasus mellonae also shows that a shedding dispersal syndrome, a feature that has often been overlooked, evolved early in the history of Pinaceae during the Early Cretaceous.

Premise of research. The extinct conifer genus Schizolepidopsis is characterized by deeply bilobed ovuliferous scales bearing two adaxial seeds. Although it is frequently placed in Pinaceae, the ev...

Premise of research. Melastomataceae are a diverse and primarily tropical family with a particularly sparse fossil record. Various biogeographic interpretations based on phylogenies, extant distrib...

Leguminosae are one of the most diverse flowering-plant groups today, but the evolutionary history of the family remains obscure because of the scarce early fossil record, particularly from lowland tropics. Here, we report ~500 compression or impression specimens with distinctive legume features collected from the Cerrejón and Bogotá Formations, Middle to Late Paleocene of Colombia. The specimens were segregated into eight fruit and six leaf morphotypes. Two bipinnate leaf morphotypes are confidently placed in the Caesalpinioideae and are the earliest record of this subfamily. Two of the fruit morphotypes are placed in the Detarioideae and Dialioideae. All other fruit and leaf morphotypes show similarities with more than one subfamily or their affinities remain uncertain. The abundant fossil fruits and leaves described here show that Leguminosae was the most important component of the earliest rainforests in northern South America c. 60–58 million years ago.

Premise of research. Recent classifications of Anacardiaceae recognize two subfamilies, Anacardioideae and Spondioideae. Most genera within Spondioideae are still recognized for having drupes with ...

Premise of research. Fossil leaves from the early Eocene Green River Formation of Wyoming and late Eocene Florissant Formation of Colorado have been studied and described here as two species in the...

— Fossil fruits of Symplocos (Ericales: Symplocaceae) are here recognized from the Pliocene of Guasca, Colombia, based on specimens formerly attributed to Cordia (Cordiaceae, Boraginales). Symplocos vera (Berry) comb. nov. is represented by 19 lignitized fruits. The fossils are recognized as belonging to Symplocos primarily by their woody endocarps that are apically truncate and that possess 3 to 5 apical germination pores and locules, and a central vascular canal extending the length of the endocarp. In several key characters they are highly congruent with the endocarps of the extant Neotropical clade S. ser. Symplocos. Some of the extant species in the series are variably 3- to 5-locular; 4-locular endocarps are otherwise rare in Symplocos, and 5-locular endocarps appear to be unique to this series. Symplocos vera is the only specifically named record of fossil Symplocos fruits with accessible voucher specimens from South America. The younger Neogene age of the fossils relative to those attributed to S. ser. Symplocos from the late Eocene of Texas, along with a report of Colombian fossil endocarps from the middle Miocene, supports the North America to South America migration inferred for this clade from molecular phylogenetic data.

The Spondioideae subfamily of the Anacardiaceae is widely distributed today in tropical regions. Recent molecular phylogenetic investigations indicate that the Spondioideae are not monophyletic, but rather comprise at least two separate clades that are difficult to distinguish using vegetative and floral characters. Nevertheless, the syndrome of fruit characters traditionally used in identifying the subfamily is useful in discriminating genera of these clades and for identification of both modern and fossil anacardiaceous fruits. Here we document the morphology and anatomy of endocarps for representatives of all extant genera traditionally treated as Spondioideae, plus two genera that have been placed close to them in molecular investigations, Buchanania and Campnosperma. All genera are characterized by drupe-like fruits with sclerified stones that vary from uni- to multilocular depending on the genus. Germination modes vary throughout the Spondioideae. Some have characteristic plug-like opercula; others have recessed bilabiate germination valves, and still others open by apical flaps or simple slits. Although most currently recognized genera appear to be monophyletic, fruit morphology indicates that current circumscriptions of Cyrtocarpa, Poupartia and Tapirira are in need of revision.

Premise of the study Hymenophyllaceae ("filmy ferns") are a widely distributed group of predominantly tropical, epiphytic ferns that also include some temperate and terrestrial species. Hymenophyllaceae are one of the earliest-diverging lineages within leptosporangiate ferns, but their fossil record is sparse, most likely because of their low fossilization potential and commonly poor preservation of their delicate, membranaceous fronds. A new species of unequivocal fossil Hymenophyllaceae, Hymenophyllum iwatsukii sp. nov., is described from the Early Cretaceous of Mongolia based on abundant and exceptionally well-preserved material. Methods Bulk lignite samples collected from Tevshiin Govi and Tugrug localities in Mongolia, were disaggregated in water, cleaned with hydrochloric and hydrofluoric acids, washed, and dried in air. Fossils were examined and compared to material of extant Hymenophyllaceae using LM and SEM. Key results The fossil fern specimens are assigned to the Hymenophyllaceae based on their membranaceous laminae with marginal sori that have sessile to short-stalked sporangia with oblique, complete annuli, and trilete, tetrahedral-globose spores. Within the family, the fossil material is assigned to the extant genus Hymenophyllum on the basis of bivalvate indusia and short, included receptacles. Conclusions Hymenophyllum iwatsukii was likely an epiphyte based on the sedimentary environment in which the fossils are preserved, the associated fossil flora, and the growth habit of extant species of Hymenophyllum. The new fossil species underlines the extent to which morphological characters in Hymenophyllum have been conserved despite significant tectonic, climatic, ecological, and floristic changes since the Early Cretaceous.

Previously unrecognized anatomical features of the cone scales of the enigmatic Early Cretaceous conifer Krassilovia mongolica include the presence of transversely oriented paracytic stomata, which is unusual for all other extinct and extant conifers. Identical stomata arepresent on co-occurring broad, linear, multiveined leaves assigned to Podozamites harrisii, providing evidence that K. mongolica and P. harrisii are the seed cones and leaves of the same extinct plant. Phylogenetic analyses of the relationships of the reconstructed Krassilovia plant place it in an informal clade that we name the Krassilovia Clade, which also includes Swedenborgia cryptomerioides–Podozamites schenkii, and Cycadocarpidium erdmanni–Podozamites schenkii. All three of these plants have linear leaves that are relatively broad compared to most living conifers, and that are also multiveined with transversely oriented paracytic stomata. We propose that these may be general features of the Krassilovia Clade. Paracytic stomata, and other features of this new group, recall features of extant and fossil Gnetales, raising questions about the phylogenetic homogeneity of the conifer clade similar to those raised by phylogenetic analyses of molecular data. Funding for this work was provided by National Science Foundation grants DEB-1748286 to P.S.H., P.R.C. and F.H., and 1348456 to P.R.C. and P.S.H., the Oak Spring Garden Foundation to F.H., and Grants-in-Aid for Scientific Research (21405010 and 24405015) from the Japan Society.

Premise of research. The two living species of Cunninghamia form a clade that is sister to the rest of the Cupressaceae sensu lato, within which the monotypic extant genus Taiwania is sister to all Cupressaceae except Cunninghamia. Seed cones of both Cunninghamia and Taiwania bear helically arranged bract-scale complexes, but a free ovuliferous scale is present only in Cunninghamia. Here, we describe two new genera of fossil seed cones similar to those of Cunninghamia and Taiwania.Methodology. Early Cretaceous (Aptian-Albian) bulk lignite samples collected from the Tevshiin Govi locality were disaggregated in water, cleaned with hydrochloric and hydrofluoric acids, washed, and dried in air.Pivotal results. Pentakonos gen. nov. has seed cones that are up to 7 mm long with ca. 25–30 helically arranged, papery bract-scale complexes that have minute teeth. Adaxially, the free tip of the membranous ovuliferous scale is denticulate, and the scale bears five small, thin-winged seeds. Pentakonos adds to the diver...

Pyrite-permineralized fruits and seeds from the London Clay Formation (Ypresian; England) in the NHMUK are stored in silicone oil to retard decay processes. X-ray micro-computed tomography (micro-CT) has revealed internal morphology for multiple holotypes (including severely cracked and encrusted specimens) scanned in the protective fluid. Silicone oil alone has a similar X-ray attenuation to parts of the specimens, causing minor uncertainty for digitally rendered surfaces, but key systematic characters are readily visualized. Further work is needed to optimize visualization of fine-scale cellular detail. Labelling and segmentation to visualize important structures is achievable with these micro-CT datasets. However, manual labelling of individual slices is required, and defining boundaries between features can be difficult due to differential pyritization and silicone oil permeation. Digital sections through specimens can be made in any orientation and digital locule casts can be produced for studies in virtual taphonomy. These achievements have been accomplished with minimal risk to specimens, which remained in silicone oil and were studied within the museum. The datasets provide a potentially permanent record of at-risk specimens, can be made widely available to researchers unable to visit the collections and to other interested parties, and they enable monitoring for future conservation.

Corystosperms, a key extinct group of Late Permian to Early Cretaceous plants, are important for understanding seed plant phylogeny, including the evolution of the angiosperm carpel and anatropous bitegmic ovule. Here, we describe a new species of corystosperm seed-bearing organ, Umkomasia mongolica sp. nov., based on hundreds of three-dimensionally preserved mesofossils from the Early Cretaceous of Mongolia. Individual seed-bearing units of U. mongolica consist of a bract subtending an axis that bifurcates, with each fork (cupule stalk) bearing a cupule near the tip. Each cupule is formed by the strongly reflexed cupule stalk and two lateral flaps that partially enclose an erect seed. The seed is borne at, or close to, the tip of the reflexed cupule stalk, with the micropyle oriented towards the stalk base. The corystosperm cupule is generally interpreted as a modified leaf that bears a seed on its abaxial surface. However, U. mongolica suggests that an earlier interpretation, in which the seed is borne directly on an axis (shoot), is equally likely. The 'axial' interpretation suggests a possible relationship of corystosperms to Ginkgo. It also suggests that the cupules of corystosperms may be less distinct from those of Caytonia than has previously been supposed.

PREMISE OF THE STUDY Chrysobalanaceae are woody plants with over 500 species in 20 genera. They are among the most common trees in tropical forests, but a sparse fossil record has limited our ability to test evolutionary and biogeographic hypotheses, and several previous reports of Chrysobalanaceae megafossils are doubtful. METHODS We prepared fossil endocarps and wood collected from the lower Miocene beds along the Panama Canal using the cellulose acetate peel technique and examined them using light microscopy. We compared the fossil endocarps with previously published fossils and with fruits from herbarium specimens. We compared the fossil wood with photographs and descriptions of extant species. KEY RESULTS Parinari endocarps can be distinguished from other genera within Chrysobalanaceae by a suite of features, i.e., thick wall, a secondary septum, seminal cavities lined with dense, woolly trichomes, and two ovate to lingulate basal germination plugs. Fossil endocarps from the Cucaracha, Culebra, and La Boca Formations confirm that Parinari was present in the neotropics by the early Miocene. CONCLUSIONS The earliest unequivocal evidence of crown-group Chrysobalanaceae is late Oligocene-early Miocene, and the genus Parinari was distinct by at least 19 million years ago. Parinari and other Chrysobalanaceae likely reached the neotropics via long-distance dispersal rather than vicariance. The presence of Parinari in the Cucaracha flora supports the interpretation of a riparian, moist tropical forest environment. Parinari was probably a canopy-dominant tree in the Cucaracha forest and took advantage of the local megafauna for seed dispersal.

Premise of research. Abundant fossil and molecular evidence suggests that all extant conifer families were established by the Early Cretaceous. However, the recognition and understanding of the lineages that lead to the evolution of these extant families remain incomplete. Late Paleozoic to Early Mesozoic Voltziales conifers—also known as transitional conifers, usually with multilobed ovuliferous scales—have been hypothesized to be among the stem lineages of modern crown conifers. This article describes an exquisitely preserved voltzian seed cone from the Aptian-Albian of Mongolia that introduces new taxonomic diversity and morphological data into the complex pattern of conifer evolution.Methodology. Bulk lignite samples collected from the Tevshiin Govi locality were disaggregated in water, cleaned with hydrochloric and hydrofluoric acids, washed, and dried in air. Fossils were examined using LM, SEM, and X-ray microtomography.Pivotal results. Krassilovia mongolica gen. et sp. nov. has seed cones with hel...

Premise of research. Humiriaceae occupy predominantly Neotropical lowland rainforests, with only a single Old World species in western Africa. Molecular divergence time estimates suggest that the family might have originated during the middle Cretaceous; however, fossil occurrences are lacking prior to the Paleocene. Here we provide new fossil evidence that expands our understanding of the paleobiogeographic history and evolution of this family.Methodology. Fossil endocarps and wood were compared with extant relatives of the family. Transverse and longitudinal sections of fossil and modern fruits were studied anatomically and morphologically.Pivotal results. Fruits of the new species, Duckesia berryi sp. n., from the Oligocene of Pacific coastal Peru (ca. 30–28.5 Ma), provide the earliest fossil evidence of Duckesia—the genus is now confined to Amazonia. We also document the earliest fossil fruit record for Sacoglottis tertiaria, from the early Oligocene (ca. 33.9–28.4 Ma) of Puerto Rico, and a new occurr...

The Phytocreneae (Icacinaceae) are a tribe of scrambling shrubs and lianas presently distributed in tropical Africa, Madagascar, and Indo-Malesia. We describe the oldest known fossils of this tribe and provide the first recognition of this group in the Neotropical fossil record based on distinctive fruit remains. Palaeophytocrene piggae sp. nov., from the late Paleocene of western North America, and Palaeophytocrene hammenii sp. nov. and cf. Phytocrene sp., from the middle-late Paleocene of Colombia, constitute the oldest confirmed records of this tribe. Pyrenacantha austroamericana sp. nov., from the Oligocene of Peru, represents an extant Old World genus known also from the Eocene fossil record of North America and Europe. Collectively, these fossils indicate that the Phytocreneae were previously established in the Neotropics, despite their current absence from the region, and may provide evidence for Paleogene floristic exchange between North and South America.

 Premise of the study: Fossil leaves of Menispermaceae were previously described from the Paleocene of Colombia. Because of strong homoplasy of leaf characters, the fossils could not be placed more specifi cally within recognized clades, and additional data were needed to specify intrafamilial and paleogeographic relationships during the Paleocene.  Methods: Fossil endocarps of Menispermaceae were collected from the Cerrej o n Formation, the recently discovered Bogot a fl ora, and Wyoming (~60 Ma). We surveyed the endocarp morphology of almost all extant genera, conducted character optimization, a molecular scaffold analysis, and critically reviewed the related fossil genera.  Key results: Parallel syndromes of fruit characters have appeared in unrelated clades of the family according to current phylogenetic reconstructions. However, mapping selected endocarp characters across those clades that contain horseshoe-shaped endocarps facilitates identifi cation and phylogenetic assessment of the fossils. Three fossil species are recognized. One of them belongs to the extant genus Stephania , which today grows only in Africa and Australasia. Palaeoluna gen. nov. is placed within the pantropical clade composed of extant Stephania , Cissampelos , and Cyclea ; this morphogenus is also recognized from the Paleocene of Wyoming. Menispina gen. nov. shows similarity with several unrelated clades.  Conclusions: The new fossils from Colombia reveal a complex paleobiogeographic history of the recognized clades within Menispermaceae, suggesting a more active exchange among neotropical, paleotropical, North American, and European paleoforests than previously recognized. In addition, the new fossils indicate that neotropical forests were an important biome for the radiation and dispersal of derived lineages in Menispermaceae after the Cretaceous – Paleogene boundary.

To place a new fossil occurrence of Sacoglottis in a broader context, we surveyed the fruit morphology of all extant genera of the Humiriaceae, conducted a cladistic analysis, and critically reviewed the fossil record for this family. Living and fossil fruits of Humiriaceae are recognized by a woody endocarp, germination valves, and, in some genera, wall cavities. The phylogenetic analysis based on 40 morphological characters yielded two most parsimonious trees indicating Vantanea as sister taxon to all genera among Humiriaceae. Schistostemon is indistinguishable from Sacoglottis in fruit morphology and is recovered as sister to Sacoglottis in the topology; we recommend restoring Schistostemon to the rank of subgenus within Sacoglottis. A review of prior published reports of fossil fruits attributed to Humiriaceae led to the rejection and/or reattribution of some records but supports recognition of Vantanea, Humiria, Humiriastrum, and Sacoglottis. The available characters do not support recognition of mul...

PREMISE OF THE STUDY The clade Bombacoideae + Malvoideae ('Malvatheca group' sensu Baum et al.) in Malvaceae comprises a mostly tropical lineage with derived taxa that now thrive in higher latitudes. The sparse fossil record, especially for Malvoideae, obscures interpretations of past distributions. We describe fossil leaves of Malvoideae from the middle-late Paleocene Cerrejon Formation in Colombia, which contains evidence for the earliest known neotropical rainforest. METHODS Fifty-six leaf compressions belonging to Malvaceae were collected from the Cerrejon Formation in northern Colombia. Leaf architectural characters were scored and optimized for 81 genera of Malvaceae. Synapomorphic characters and unique character combinations support natural affinities for the fossil leaves. Fossil pollen from the same formation was also assessed. KEY RESULTS Despite convergence of overall leaf architecture among many Malvaceae, Malvaciphyllum macondicus sp. nov. can be assigned to the clade Eumalvoideae because of distal and proximal bifurcations of the costal secondary and agrophic veins, a synapomorphy for this clade. CONCLUSIONS The leaf compressions, the oldest fossils for Eumalvoideae, indicate a minimum divergence time of 58-60 Ma, older than existing estimates from molecular analyses of living species. The abundance of eumalvoid leaves and of bombacoid pollen in the midlate Paleocene of Colombia suggests that the Malvatheca group (Malvoideae + Bombacoideae) was already a common element in neotropical forests and does not support an Australasian origin for Eumalvoideae.

The origin and processes creating the high diversity of plant species in neotropical rain forests and their floristic composition and multistratitified forest structure are still uncertain. Here, we studied one of the most common leaf morphotypes of the Cerrejon flora (middle-late Paleocene, ca. 60-58 Ma), Guajira, Colombia, that contains one of the oldest records of neotropical rain forest floras. Fifty-seven leaf specimens were carefully examined with a focus on general morphology, venation patterns, and cuticular characteristics. The analysis allowed us to recognize four new species that were assigned to the fossil-leaf genus Menispermites on the basis of an ovate leaf shape with cordate to truncate bases, actinodromous primary venation, brochidodromous secondary venation, percurrent tertiary venation, regular polygonal reticulate fourth and fifth venation, well-developed polygonal areoles, entire margin, and the presence of a fimbrial vein. This set of characters suggests a possible affinity with the pantropical angiosperm family Menispermaceae. The predominantly climbing habit of this family suggests that the Cerrejon Paleocene tropical rain forest was already multistratified. These findings represent the earliest record for the family in northern South America.

Palms are a monophyletic group with a dominantly tropical distribution; however, their fossil record in low latitudes is strikingly scarce. In this paper, we describe fossil leaves, inflorescences, and fruits of palms from the middle to late Paleocene Cerrejon Formation, outcropping in the Rancheria River Valley, northern Colombia. The fossils demonstrate the presence of at least five palm morphospecies in the basin ca. 60 Ma. We compare the morphology of the fossils with extant palms and conclude that they belong to at least three palm lineages: the pantropical Cocoseae of the subfamily Arecoideae, the monotypic genus Nypa, and either Calamoideae or Coryphoideae. The fossil fruits and inflorescences are among the oldest megafossil records of these groups and demonstrate that the divergence of the Cocoseae was more than 60 Ma, earlier than has previously been thought. These fossils are useful in tracing the range expansion or contraction of historical or current neotropical elements and also have profound implications for the understanding of the evolution of neotropical rainforests.

Both the fossil record and molecular data support a long evolutionary history for the Araceae. Although the family is diverse in tropical America today, most araceous fossils, however, have been recorded from middle and high latitudes. Here, we report fossil leaves of Araceae from the middle-late Paleocene of northern Colombia, and review fossil araceous pollen grains from the same interval. Two of the fossil leaf species are placed in the new fossil morphogenus Petrocardium Herrera, Jaramillo, Dilcher, Wing et Gomez-N gen. nov.; these fossils are very similar in leaf morphology to extant Anthurium; however, their relationship to the genus is still unresolved. A third fossil leaf type from Cerrejon is recognized as a species of the extant genus Montrichardia, the first fossil record for this genus. These fossils inhabited a coastal rainforest ∼60-58 million years ago with broadly similar habitat preferences to modern Araceae.

16 páginas, 2 tablas, 5 figuras., Paleobotanists have long used models based on leaf size and shape to reconstruct paleoclimate. However, most models incorporate a single variable or use traits that are not physiologically or functionally linked to climate, limiting their predictive power. Further, they often underestimate paleotemperature relative to other proxies. • Here we quantify leaf–climate correlations from 92 globally distributed, climatically diverse sites, and explore potential confounding factors. Multiple linear regression models for mean annual temperature (MAT) and mean annual precipitation (MAP) are developed and applied to nine well-studied fossil floras. • We find that leaves in cold climates typically have larger, more numerous teeth, and are more highly dissected. Leaf habit (deciduous vs evergreen), local water availability, and phylogenetic history all affect these relationships. Leaves in wet climates are larger and have fewer, smaller teeth. Our multivariate MAT and MAP models offer moderate improvements in precision over univariate approaches (± 4.0 vs 4.8°C for MAT) and strong improvements in accuracy. For example, our provisional MAT estimates for most North American fossil floras are considerably warmer and in better agreement with independent paleoclimate evidence. • Our study demonstrates that the inclusion of additional leaf traits that are functionally linked to climate improves paleoclimate reconstructions. This work also illustrates the need for better understanding of the impact of phylogeny and leaf habit on leaf–climate relationships., Work at Wesleyan was supported primarily by the National Science Foundation (NSF) (grant EAR-0742363 to DLR). Funding for the Patagonia fossil collections (Laguna del Hunco and P. Loros) was supported by NSF and the National Geographic Society (grants DEB-0345750, DEB- 0919071, and NGS 7337-02 to Peter Wilf and others).