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Gymnosperm
Naked seed plants without fruit enclosure.
Naked ovules
Ovary without ovules, characteristic of gymnosperms.
Paleozoic era
Time period gymnosperms originated (541-252 million years ago).
Cretaceous period
Dominant era for gymnosperms in Mesozoic.
Cycadofilicales
Extinct primitive gymnosperm group.
Cordaitales
Another extinct group of primitive gymnosperms.
Examples of Gymnosperms
Includes Cycas, Pinus, Gnetum, Ginkgo, Cedrus.
Sporophytic plant body
Plant body differentiated into root, stem, leaves.
Xerophytic characters
Adaptations for surviving in dry environments.
Coralloid root
Symbiotic root in Cycas with blue-green algae.
Mycorrhiza
Fungal association aiding nutrient absorption in Pinus.
N2 fixation
Process facilitated by algae in Cycas roots.
Erect stem
Typically branched and woody in gymnosperms.
Leaf scar
Characteristic feature indicating past leaf attachment.
Dimorphic leaves
Leaves exhibit two distinct forms.
Foliage leaves
Green, simple, small, and deciduous leaves.
Circinate venation
Young leaves of Cycas curled inward.
Pteridophytic origin
Cycas connects gymnosperms to pteridophytes.
Thick cuticle
Protective layer on gymnosperm leaves.
Sunken stomata
Stomata positioned below leaf surface for water retention.
Palisade and spongy tissues
Mesophyll layers differentiated in gymnosperm leaves.
Transfusion tissue
Facilitates nutrient lateral transfer in leaves.
Open collateral vascular bundle
Type of vascular bundle in gymnosperms.
Tracheids
Xylem cells present in gymnosperms.
Eusporangiate type
Microsporangial development method in gymnosperms.
Megasporophyll
Structure bearing megasporangia in gymnosperms.
Orthotropous ovules
Ovules with a straight orientation in gymnosperms.
Anemophily
Wind pollination method used by gymnosperms.
Microsporangia
Produced on microsporophyll in gymnosperms.
Female cone
Aggregation of megasporophylls forming reproductive structure.
Monosporangiate cones
Cones with single type of sporangia.
Microspores
Pollen grains released during male gametophyte stages.
Siphonogamous fertilization
Fertilization through pollen tube mechanism.
Pollen tube
Structure that carries sperm to ovule.
Non-motile male gametes
Male gametes that do not move, except in Cycas and Ginkgo.
Archegonia
Female reproductive structure containing egg cell.
Cycad archegonia
Multiple archegonia present in Cycas species.
Pinus archegonia
Single archegonium found in Pinus species.
Neck canal cells
Absent in gymnosperms, part of archegonium.
Meroblastic development
Embryo develops from part of zygote.
Haploid endosperm
Endosperm formed before fertilization, haploid in nature.
Double fertilization
Absence of double fertilization in gymnosperms.
Polyembryony
Development of multiple embryos from one zygote.
Cycadofilicales
Extinct order of gymnosperms.
Bennettitales
Extinct gymnosperm order, related to cycads.
Cycadales
Order of gymnosperms from Mesozoic to present.
Cordaitales
Extinct gymnosperm order from Paleozoic era.
Ginkgoales
Order including Ginkgo, from Paleozoic to present.
Coniferales
Order of gymnosperms from Paleozoic to present.
Gnetales
Recent order of gymnosperms.
Cycadophyta
Group including cycads, classified by Chamberlain.
Coniferophyta
Group including conifers, classified by Chamberlain.
Phyllospermae
Group of gymnosperms proposed by B. Sahni.
Stachyospermae
Group of gymnosperms proposed by B. Sahni.
Christenhusz classification
Recent classification dividing gymnosperms into four subclasses.
Cycadidae
Subclass of gymnosperms including cycads.
Ginkgoidae
Subclass of gymnosperms including Ginkgo species.
Gnetidae
Subclass of gymnosperms including Gnetum.
Pinidae
Subclass of gymnosperms including pines.
Angiosperms
Flowering plants producing flowers and fruits.
Phylum Anthophyta
Single phylum encompassing all angiosperms.
Monocots
Angiosperms with leaves showing parallel venation.
Dicots
Angiosperms with netlike leaf venation.
Monocots
A monophyletic group of flowering plants.
Eudicots
A major clade within the dicots.
Angiosperms
Flowering plants with enclosed seeds.
Dicots
Plants with dicot anatomy, not monophyletic.
Clade
A group of organisms with a common ancestor.
Xylem
Vascular tissue for water transport in plants.
Tracheids
Long, tapered cells in xylem for support.
Vessel elements
Specialized xylem cells for efficient water transport.
Flower
Specialized reproductive structure of angiosperms.
Pollination
Transfer of pollen from male to female organs.
Sepals
Modified leaves enclosing a flower before opening.
Petals
Brightly colored leaves attracting pollinators.
Stamens
Male reproductive organs producing microspores.
Anther
Part of stamen where pollen is produced.
Carpals
Female reproductive organs producing megaspores.
Stigma
Sticky tip of carpal receiving pollen.
Style
Structure leading from stigma to ovary.
Ovary
Base of carpal containing ovules.
Ovules
Structures that develop into seeds after fertilization.
Seed
Developed ovule containing embryo and nutrients.
Wind pollination
Pollination method relying on air currents.
Animal pollination
Pollination facilitated by insects and animals.
Fibers cells
Specialized cells in xylem for structural support.
Amborella trichopoda
Oldest known angiosperm lineage survivor.
Grasses
Dense populations relying on wind for pollination.
Evolutionary refinements
Adaptations enhancing plant survival and reproduction.
Gymnosperms
Non-flowering plants with exposed seeds.
