Basic features of gymnosperm systematics and phylogeny as evidenced by the fossil record

Evolution and classification of flowering plants

1979 • 1,692 citations

Flowering Plants. Evolution above the Species Level

1975 • 1,451 citations

The Evolution and Classification of Flowering Plants.

1989 • 1,325 citations

Flowering Plants

1974 • 1,297 citations

Flowering Plants--Origin and Dispersal.

1970 • 1,185 citations

Morphology of Vascular Plants

1972 • 677 citations

The Yorkshire Jurassic flora

1961 • 505 citations

Morphology of the angiosperms

1961 • 474 citations

Die Grundlagen des natürlichen Systems, der vergleichenden Anatomie und der Phylogenetik : theoretische Morphologie und Systematik I

1952 • 393 citations

The distribution of conifer and taxad genera in time and space

1963 • 359 citations

Handbuch der Pflanzenanatomie

1925 • 342 citations

Syllabus der Pflanzenfamilien

1892 • 330 citations

Atlas of Palaeobiogeography.

1973 • 306 citations

Cheirolepidiaceae: Biology, structure and paleoecology

1982 • 299 citations

Paleobotany, Paleoecology, and Evolution.

1981 • 268 citations

Die Phylogenie der Pflanzen . Dr. Walter Zimmerman, University of Tübingen. Jena, Verlag von Gustav Fischer, 1930.

1930 • 216 citations

Mesozoic conifers

1977 • 216 citations

The biology ofGlossopteris: evidence from petrified seed-bearing and pollen-bearing organs

1977 • 175 citations

Paleobotany: An Introduction to Fossil Plant Biology

1981 • 173 citations

Early angiosperm reproduction: An introductory report

1979 • 164 citations

The Araucariaceae: An evolutionary perspective

1982 • 150 citations

Stelar morphology and the primary vascular system of seed plants

1982 • 149 citations

Reconstructing Triassic vegetation of eastern Australasia: a new approach for the biostratigraphy of Gondwanaland

1977 • 144 citations

Morphology of Angiosperms

2010 • 127 citations

VII. On some pteridospermous plants from the Mesozoic rocks of South Africa

1932 • 125 citations

ON THE HIGHER TAXA OF EMBRYOBIONTA

1966 • 111 citations

THE APPEARANCE OF GYMNOSPERMOUS STRUCTURE

1970 • 111 citations

Arguments for a glossopterid ancestry of angiosperms

1981 • 107 citations

The callistophytales (Pteridospermopsida): Reproductively sophisticated paleozoic gymnosperms

1981 • 106 citations

New interpretations of the earliest conifers

1982 • 106 citations

The evolution of flowering plants

1960 • 105 citations

La flore du Grès à Voltzia (Buntsandstein supérieur) des Vosges du Nord (France). Morphologie, anatomie, interprétations phylogénique et paléogéographique

1978 • 102 citations

Paleozoic origin of the cycads

1976 • 100 citations

Studies in paleobotany

1961 • 99 citations

Pollination biology and reproduction in early seed plants

1979 • 97 citations

Exine Structures in some fossil and recent spores and pollen as revealed by light and electron microscopy

1966 • 95 citations

Programs of Gene Action and Progressive Evolution

1976 • 92 citations

Die Floren des Erdaltertums

1977 • 92 citations

Current status of paleozoic and mesozoic conifers

1982 • 86 citations

Plant morphology in its nomothetical aspects

1973 • 85 citations

Morphologic interpretation of fertile structures in glossopterid gymnosperms

1976 • 83 citations

Paleozoic seed fern pollen organs

1979 • 82 citations

The earliest seeds

1981 • 82 citations

ASPECTS OF PERMIAN PALAEOBOTANY AND PALYNOLOGY

1982 • 80 citations

The origin of angiosperms

1977 • 79 citations

The Natural Philosophy of Plant Form

2012 • 73 citations

Early Seed Plants

1963 • 73 citations

Morphologic variability of Pennsylvanian lyginopterid seed ferns

1981 • 73 citations

Paläobiologie der Pflanzen

1956 • 72 citations

The Mesozoic gymnosperms

1976 • 70 citations

The current status of medullosan seed ferns

1981 • 70 citations

Archaeosperma arnoldii-A Cupulate Seed from the Upper Devonian of North America

1968 • 70 citations

Evidence of Pollen Tubes in Paleozoic Pteridosperms

1972 • 69 citations

Ontogeny of progymnosperms. II. Shoots of Upper Devonian Archaeopteridales

1978 • 69 citations

A COMPARATIVE STUDY OF THE PRIMARY VASCULAR SYSTEM OF CONIFERS. I. GENERA WITH HELICAL PHYLLOTAXIS

1968 • 68 citations

The lower Gondwana gymnosperms and their relationships

1982 • 63 citations

Die Koniferen des Oberkarbons und des unteren Perms I-VII

1938 • 63 citations

HETEROSPORY AND THE ORIGIN OF THE SEED HABIT

1970 • 62 citations

The earliest conifer

1974 • 61 citations

Regulatory gene adaptation: An evolutionary model

1980 • 60 citations

The medullosan pteridosperms

1956 • 59 citations

Observations on the Lower Carboniferous genusPitusWitham

1979 • 59 citations

Rhacophyton from the Upper Devonian of West Virginia

1968 • 58 citations

VESSEL STRUCTURE OF GNETUM AND THE ORIGIN OF ANGIOSPERMS

1982 • 57 citations

CAULINE VASCULATURE AND LEAF TRACE PRODUCTION IN MEDULLOSAN PTERIDOSPERMS

1974 • 52 citations

The ultrastructure and reproductive significance of Monoletes (Pteridospermales) pollen

1978 • 52 citations

First Devonian platyspermic seed and its implications in gymnosperm evolution

1977 • 50 citations

Metasequoia milleri n.sp., anatomically preserved pollen cones from the Middle Eocene (Allenby Formation) of British Columbia

1979 • 48 citations

The morphology of gymnosperms : the structure and evolution of primitive seed-plants

1965 • 47 citations

Morphology and Ultrastructure of Four Pennsylvanian Prepollen Types

1978 • 47 citations

The characters of the fossil plant Gigantopteris Schenk and its occurrence in North America

1912 • 43 citations

PROBABLE ATTACHMENT OF THE DOLEROTHECA CAMPANULUM TO A MYELOXYLON-ALETHOPTERIS TYPE FROND

1974 • 43 citations

FERTILE CONIFEROPHYTE REMAINS FROM THE LATE TRIASSIC DEEP RIVER BASIN, NORTH CAROLINA

1973 • 39 citations

Paläozoische und mesozoische Floren Eurasiens und die Phytogeographie dieser Zeit

1978 • 39 citations

A Vegetative Mutant, and the Principle of Homoeosis in Plants

1909 • 39 citations

The evolution of miospore polarity

1970 • 39 citations

Ultrastructural studies of paleozoic seed fern pollen: Sporoderm development

1982 • 39 citations

Sistemática y vinculaciones de las Corystospermaceae H. Thomas

1981 • 39 citations

Perspectives on the origin of cycads and cycadeoids

1982 • 39 citations

THE EVOLUTION OF THE OVULE

1964 • 39 citations

Studies on the cupulate seed genus Hydrasperma Long from Berwickshire and East Lothian in Scotland and County Kerry in Ireland

1980 • 38 citations

Evolutionary trends in fossil gymnosperm pollen

1976 • 36 citations

More evidence for a slender growth habit in Mesozoic cycadophytes

1976 • 35 citations

Cladostrobus and the systematics of cordaitalean leaves

1975 • 34 citations

QUAESTORA AMPLECTA GEN. ET SP. N., A STRUCTURALLY SIMPLE MEDULLOSAN STEM FROM THE UPPER MISSISSIPPIAN OF ARKANSAS

1980 • 34 citations

LASIOSTROBUS GEN. N., A STAMINATE STROBILUS OF GYMNOSPERMOUS AFFINITY FROM THE PENNSYLVANIAN OF NORTH AMERICA

1970 • 34 citations

4.—On the Structure of a Petrified Stem and some Associated Seeds from the Lower Carboniferous Rocks of East Lothian, Scotland

1973 • 33 citations

Eddya sullivanensis , gen. et sp. nov., a Plant of Gymnospermic Morphology from the Upper Devonian of New York

1967 • 32 citations

New Observations on the Branching of Carboniferous Ferns and Pteridosperms

1982 • 32 citations

CORDAIANTHUS DUQUESNENSIS SP. NOV., ANATOMICALLY PRESERVED OVULATE CONES FROM THE UPPER PENNSYLVANIAN OF OHIO

1982 • 31 citations

THE NATURAL AFFINITY OF THE CARBONIFEROUS SEED, CALLOSPERMARION

1970 • 29 citations

Phylogénie générale des Calliptéridiacées (Pteridospermopsida)

1977 • 29 citations

Simulated Wind Pollination and Airflow Around Ovules of Some Early Seed Plants

1981 • 28 citations

Vakhrameev, V. A., Dobruskina, I. A., Meyen, S. V. & Zaklinskaja, E. D., Paläozoische und mesozoische Floren Eurasiens und die Phytogeographie dieser Zeit. 300 S., 30 Abb. VEB Gustav Fischer Verlag. Jena, 1978

1980 • 26 citations

Denkania Indica gen. et. sp. nov. A glossopteridean fructification from the lower gondwana of India

1971 • 26 citations

CALLANDRIUM CALLISTOPHYTOIDES, GEN. ET SP. NOV., THE PROBABLE POLLEN‐BEARING ORGAN OF THE SEED FERN, CALLISTOPHYTON

1970 • 26 citations

Nucellangium: Gametophytic Structure and Relationship to Cordaites

1976 • 26 citations

Paleobotany: Perspectives in 1980

1981 • 25 citations

AN ANATOMICALLY PRESERVED POTONIEA WITH IN SITU SPORES FROM THE PENNSYLVANIAN OF ILLINOIS

1978 • 25 citations

On the structure of buriadia heterophylla (feistmantel) Seward & Sahni and its fructification

1967 • 24 citations

MORE EVIDENCE FOR CONIFER DIVERSITY IN THE UPPER TRIASSIC OF NORTH CAROLINA

1981 • 24 citations

Some comments on the origin and evolution of conifers

1981 • 22 citations

Paracytic (Syndetocheilic) Stomata in Carboniferous Seed Ferns

1976 • 22 citations

Origin and Dispersal of Flowering Plants

1959 • 21 citations

Die räto-jurassischen Floren des Iran und Afghanistans. 4. Die rätische Zwitterblüte Irania hermaphroditica nov. spec. und ihre Bedeutung für die Phylogenie der Angiospermen

1977 • 21 citations

A NEW STRUCTURALLY PRESERVED PENNSYLVANIAN CORDAITEAN POLLEN ORGAN

1979 • 21 citations

Tinsleya, a new genus of seed-bearing callipterid plants from the Permian of north-central Texas

1966 • 20 citations

Two Early Mississippian Seeds from the Price Formation of Southwestern Virginia

1977 • 20 citations

THE PRIMARY VASCULATURE OF CORDAIANTHUS CONCINNUS

1977 • 19 citations

The ultrastructure and reproductive significance of Lasiostrobus microspores

1977 • 18 citations

A Reconsideration of Stephanospermum

1963 • 18 citations

Les plantes fossiles dans leurs rapports avec les végétaux vivants : éléments de paléobotanique et de morphologie comparée

1968 • 18 citations

On the fine structure of cell walls of some gymnosperm pallen

1960 • 17 citations

Anatomie der Gymnospermen-Samen

1937 • 17 citations

15.—Calathopteris heterophyllagen. et sp. nov., a Lower Carboniferous Pteridosperm bearing Two Kinds of Petioles

1976 • 17 citations

MITROSPERMUM VINCULUM SP. NOV., A CARDIOCARPALEAN OVULE FROM THE UPPER PENNSYLVANIAN OF OHIO

1980 • 16 citations

Sandrewia, n. gen., a problematical plant from the Lower Permian of Texas and Kansas

1975 • 16 citations

BOSTONIA PERPLEXA GEN. ET SP. NOV., A CALAMOPITYAN AXIS FROM THE NEW ALBANY SHALE OF KENTUCKY

1978 • 16 citations

The Contrasting Plant Assemblages from Permian and Triassic Deposits in Southern Continents [Abstract]

1973 • 16 citations

The neotenous origin of the pollen organ of the gymnosperm Cycadeoidea and implications for the origin of higher taxa

1980 • 15 citations

Dichophyllum Moorei and Certain Associated Seeds

1941 • 15 citations

A FERTILE SPECIES OF TRIPHYLLOPTERIS FROM THE EARLY CARBONIFEROUS (MISSISSIPPIAN) OF SOUTHWESTERN VIRGINIA

1980 • 15 citations

On the structure of leaves of Rhabdotaenia Pant from the Raniganj coalfield, India

1963 • 14 citations

EARLY SEED PLANT WIND POLLINATION STUDIES: A COMMENTARY

1982 • 12 citations

A pinnate leaf with reticulate venation from the Permian of New South Wales

1977 • 11 citations

New interpretation of Gaussia (Vojnovskyales)

1981 • 11 citations

Morphology of the seed-scale complex in Picea abies (L.) Karst. (Pinaceae)

1974 • 11 citations

The neotenous origin of the pollen organ of the gymnosperm Cycadeoidea and implications for the origin of higher taxa

1980 • 10 citations

Permian predecessors of the mesozoic pteridosperms in western Angaraland, U.S.S.R.

1979 • 10 citations

The Natural Philosophy of Plant Form

1971 • 9 citations

Canipa quadrifida, gen. et sp. nov., a Synangial Fructification from the Middle Pennsylvanian of West Virginia

1969 • 8 citations

The theory of type and the natural system

1925 • 8 citations

THE SO-CALLED “MEGASPOROPHYLL” OF CYCAS - A MORPHOLOGICAL MISCONCEPTION.ITS BEARING ON THE PHYLOGENY AND THE CLASSIFICATION OF THE CYCADOPHYTA

1963 • 7 citations

WHAT IS THE VASCULAR ARCHITECTURE OF COMPLEX MEDULLOSAN POLLEN ORGANS?

1982 • 3 citations