Angiosperms: Members of the group of vascular plants which bear flowers. They are differentiated from GYMNOSPERMS by their production of seeds within a closed chamber (OVARY, PLANT). The Angiosperms division is composed of two classes, the monocotyledons (Liliopsida) and dicotyledons (Magnoliopsida). Angiosperms represent approximately 80% of all known living plants.Gymnosperms: Gymnosperms are a group of vascular plants whose seeds are not enclosed by a ripened ovary (fruit), in contrast to ANGIOSPERMS whose seeds are surrounded by an ovary wall. The seeds of many gymnosperms (literally, "naked seed") are borne in cones and are not visible. Taxonomists now recognize four distinct divisions of extant gymnospermous plants (CONIFEROPHYTA; CYCADOPHYTA; GINKGOPHYTA; and GNETOPHYTA).Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Coniferophyta: A plant division of GYMNOSPERMS consisting of cone-bearing trees and shrubs.Flowers: The reproductive organs of plants.Genes, Plant: The functional hereditary units of PLANTS.Nymphaeaceae: The sour gum plant family of the order Nymphaeales, subclass Magnoliidae, class Magnoliopsida. All have horizontal or hanging branches and broad alternate leaves, and they are dioecious (male and female flowers on different plants).Genome, Plant: The genetic complement of a plant (PLANTS) as represented in its DNA.Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.DNA, Plant: Deoxyribonucleic acid that makes up the genetic material of plants.Ovule: The element in plants that contains the female GAMETOPHYTES.Nymphaea: A plant genus of the family NYMPHAEACEAE. The common name of lotus is also used for LOTUS and NELUMBO.Nuphar: A plant genus of the family NYMPHAEACEAE. Members contain sesquiterpene thioalkaloids.Biological Evolution: The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.Botany: The study of the origin, structure, development, growth, function, genetics, and reproduction of plants.Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.DNA, Chloroplast: Deoxyribonucleic acid that makes up the genetic material of CHLOROPLASTS.Picea: A plant genus in the family PINACEAE, order Pinales, class Pinopsida, division Coniferophyta. They are evergreen, pyramidal trees with whorled branches and thin, scaly bark. Each of the linear, spirally arranged leaves is jointed near the stem on a separate woody base.Bryophyta: A division of the plant kingdom. Bryophyta contains the subdivision, Musci, which contains the classes: Andreaeopsida, BRYOPSIDA, and SPHAGNOPSIDA.Genome, Plastid: The genetic complement of PLASTIDS as represented in their DNA.Fossils: Remains, impressions, or traces of animals or plants of past geological times which have been preserved in the earth's crust.Plants: Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.Selaginellaceae: A plant family of the order Selaginellales, class Lycopodiopsida, division Lycopodiophyta, subkingdom Tracheobionta. Members contain bilobetin. The rarely used common name of resurrection plant is mainly used with CRATEROSTIGMA.Ferns: Seedless nonflowering plants of the class Filicinae. They reproduce by spores that appear as dots on the underside of feathery fronds. In earlier classifications the Pteridophyta included the club mosses, horsetails, ferns, and various fossil groups. In more recent classifications, pteridophytes and spermatophytes (seed-bearing plants) are classified in the Subkingdom Tracheobionta (also known as Tracheophyta).Cycas: A plant genus of the family Cycadaceae, order Cycadales, class Cycadopsida, division CYCADOPHYTA of palm-like trees. It is a source of CYCASIN, the beta-D-glucoside of methylazoxymethanol.Alismatidae: A plant subclass of the class Liliopsida (monocotyledons) in the Chronquist classification system. This is equivalent to the Alismatales order in the APG classification system. It is a primitive group of more or less aquatic plants.Pollen: The fertilizing element of plants that contains the male GAMETOPHYTES.Annona: A plant genus of the family ANNONACEAE. It has edible fruit and seeds which contain acetogenins and benzoquinazoline and other alkaloids.Pollination: The transfer of POLLEN grains (male gametes) to the plant ovule (female gamete).Gene Expression Regulation, Plant: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.Plastids: Self-replicating cytoplasmic organelles of plant and algal cells that contain pigments and may synthesize and accumulate various substances. PLASTID GENOMES are used in phylogenetic studies.Seeds: The encapsulated embryos of flowering plants. They are used as is or for animal feed because of the high content of concentrated nutrients like starches, proteins, and fats. Rapeseed, cottonseed, and sunflower seed are also produced for the oils (fats) they yield.Trees: Woody, usually tall, perennial higher plants (Angiosperms, Gymnosperms, and some Pterophyta) having usually a main stem and numerous branches.Genome Size: The amount of DNA (or RNA) in one copy of a genome.Arabidopsis: A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.Pollen Tube: A growth from a pollen grain down into the flower style which allows two sperm to pass, one to the ovum within the ovule, and the other to the central cell of the ovule to produce endosperm of SEEDS.Liriodendron: A plant genus of the family MAGNOLIACEAE. Members include hardwood trees of eastern North America with distinct large tuliplike flowers.Geraniaceae: A plant family of the order Geraniales, subclass Rosidae, class Magnoliopsida.RNA, Plant: Ribonucleic acid in plants having regulatory and catalytic roles as well as involvement in protein synthesis.Bryopsida: A class of plants within the Bryophyta comprising the mosses, which are found in both damp (including freshwater) and drier situations. Mosses possess erect or prostrate leafless stems, which give rise to leafless stalks bearing capsules. Spores formed in the capsules are released and grow to produce new plants. (Concise Dictionary of Biology, 1990). Many small plants bearing the name moss are in fact not mosses. The "moss" found on the north side of trees is actually a green alga (CHLOROPHYTA). Irish moss is really a red alga (RHODOPHYTA). Beard lichen (beard moss), Iceland moss, oak moss, and reindeer moss are actually LICHENS. Spanish moss is a common name for both LICHENS and an air plant (TILLANDSIA usneoides) of the pineapple family. Club moss is an evergreen herb of the family LYCOPODIACEAE.Aristolochia: A plant genus of the family ARISTOLOCHIACEAE. Species of this genus have been used in traditional medicine but they contain aristolochic acid which is associated with nephropathy. These are sometimes called 'snakeroot' but that name is also used with a number of other plants such as POLYGALA; SANICULA; ASARUM; ARISTOLOCHIA; AGERATINA; and others.Plant Leaves: Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Germ Cells, Plant: The reproductive cells of plants.MADS Domain Proteins: A superfamily of proteins that share a highly conserved MADS domain sequence motif. The term MADS refers to the first four members which were MCM1 PROTEIN; AGAMOUS 1 PROTEIN; DEFICIENS PROTEIN; and SERUM RESPONSE FACTOR. Many MADS domain proteins have been found in species from all eukaryotic kingdoms. They play an important role in development, especially in plants where they have an important role in flower development.Gene Duplication: Processes occurring in various organisms by which new genes are copied. Gene duplication may result in a MULTIGENE FAMILY; supergenes or PSEUDOGENES.Embryophyta: Higher plants that live primarily in terrestrial habitats, although some are secondarily aquatic. Most obtain their energy from PHOTOSYNTHESIS. They comprise the vascular and non-vascular plants.Tracheobionta: A subset of various vascular plants (also known as the Tracheophyta) which include seed-bearing and non seed-bearing species.Chloroplasts: Plant cell inclusion bodies that contain the photosynthetic pigment CHLOROPHYLL, which is associated with the membrane of THYLAKOIDS. Chloroplasts occur in cells of leaves and young stems of plants. They are also found in some forms of PHYTOPLANKTON such as HAPTOPHYTA; DINOFLAGELLATES; DIATOMS; and CRYPTOPHYTA.Zamiaceae: A plant family of the order Cycadales, class Cycadopsida, division CYCADOPHYTA.Endosperm: Nutritive tissue of the seeds of flowering plants that surrounds the EMBRYOS. It is produced by a parallel process of fertilization in which a second male gamete from the pollen grain fuses with two female nuclei within the embryo sac. The endosperm varies in ploidy and contains reserves of starch, oils, and proteins, making it an important source of human nutrition.Hydrocharitaceae: A plant family of the order Hydrocharitales, subclass ALISMATIDAE, class Liliopsida (monocotyledons).Genome, Chloroplast: The genetic complement of CHLOROPLASTS as represented in their DNA.Biodiversity: The variety of all native living organisms and their various forms and interrelationships.Pinus: A plant genus in the family PINACEAE, order Pinales, class Pinopsida, division Coniferophyta. They are evergreen trees mainly in temperate climates.Araceae: A plant family of the order Arales, subclass Arecidae, class Liliopsida (monocot). Many members contain OXALIC ACID and calcium oxalate (OXALATES).Arabidopsis Proteins: Proteins that originate from plants species belonging to the genus ARABIDOPSIS. The most intensely studied species of Arabidopsis, Arabidopsis thaliana, is commonly used in laboratory experiments.Plant Shoots: New immature growth of a plant including stem, leaves, tips of branches, and SEEDLINGS.Pinus taeda: A plant species of the genus PINUS which is the subject of genetic study.Persea: A plant genus in the LAURACEAE family. The tree, Persea americana Mill., is known for the Avocado fruit, the food of commerce.Orobanche: A plant genus of the family OROBANCHACEAE. Lacking chlorophyll, they are nonphotosynthetic parasitic plants. The common name is similar to Broom or Scotch Broom (CYTISUS) or Butcher's Broom (RUSCUS) or Desert Broom (BACCHARIS) or Spanish Broom (SPARTIUM) or Brome (BROMUS).Orchidaceae: A plant family of the order Orchidales, subclass Liliidae, class Liliopsida (monocotyledons). All orchids have the same bilaterally symmetrical flower structure, with three sepals, but the flowers vary greatly in color and shape.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Malpighiaceae: A plant family of the order Polygalales, subclass Rosidae class, Magnoliopsida that are mostly shrubs and small trees. Many of the members contain indole alkaloids.Crassulaceae: The stonecrop plant family of the order ROSALES, subclass Rosidae, class Magnoliopsida that grow in warm, dry regions. The leaves are thick. The flower clusters are red, yellow, or white.Multigene Family: A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)Oryza sativa: Annual cereal grass of the family POACEAE and its edible starchy grain, rice, which is the staple food of roughly one-half of the world's population.Lignin: The most abundant natural aromatic organic polymer found in all vascular plants. Lignin together with cellulose and hemicellulose are the major cell wall components of the fibers of all wood and grass species. Lignin is composed of coniferyl, p-coumaryl, and sinapyl alcohols in varying ratios in different plant species. (From Merck Index, 11th ed)Genome, Mitochondrial: The genetic complement of MITOCHONDRIA as represented in their DNA.Self-Fertilization: The fusion of a male gamete with a female gamete from the same individual animal or plant.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Plant Physiological Phenomena: The physiological processes, properties, and states characteristic of plants.Campanulaceae: A plant family of the order Campanulales, subclass Asteridae, class MagnoliopsidaSequence Alignment: The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.Genes, Mitochondrial: Genes that are located on the MITOCHONDRIAL DNA. Mitochondrial inheritance is often referred to as maternal inheritance but should be differentiated from maternal inheritance that is transmitted chromosomally.Flowering Tops: Tops of plants when in flower, including the stems, leaves and blooms.Polyploidy: The chromosomal constitution of a cell containing multiples of the normal number of CHROMOSOMES; includes triploidy (symbol: 3N), tetraploidy (symbol: 4N), etc.Meristem: A group of plant cells that are capable of dividing infinitely and whose main function is the production of new growth at the growing tip of a root or stem. (From Concise Dictionary of Biology, 1990)Reproduction: The total process by which organisms produce offspring. (Stedman, 25th ed)Viburnum: A plant genus in the family CAPRIFOLIACEAE. The common name derives from its traditional use for menstrual cramps. It is a source of viburnine, valerianic acid, vibsanin, and ursolic acid. Note that true cranberry is VACCINIUM MACROCARPON.Plant Stomata: Closable openings in the epidermis of plants on the underside of leaves. They allow the exchange of gases between the internal tissues of the plant and the outside atmosphere.Silene: A plant genus of the family CARYOPHYLLACEAE. The common name of campion is also used with LYCHNIS. The common name of 'pink' can be confused with other plants.Populus: A plant genus of the family SALICACEAE. Balm of Gilead is a common name used for P. candicans, or P. gileadensis, or P. jackii, and sometimes also used for ABIES BALSAMEA or for COMMIPHORA.Genetic Variation: Genotypic differences observed among individuals in a population.Tropical Climate: A climate which is typical of equatorial and tropical regions, i.e., one with continually high temperatures with considerable precipitation, at least during part of the year. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Plant Infertility: The failure of PLANTS to complete fertilization and obtain seed (SEEDS) as a result of defective POLLEN or ovules, or other aberrations. (Dict. of Plant Genet. and Mol. Biol., 1998)Plant Transpiration: The loss of water vapor by plants to the atmosphere. It occurs mainly from the leaves through pores (stomata) whose primary function is gas exchange. The water is replaced by a continuous column of water moving upwards from the roots within the xylem vessels. (Concise Dictionary of Biology, 1990)Nelumbo: A plant genus of the family NELUMBONACEAE. The common name of lotus is also for LOTUS and NYMPHAEA.Solanaceae: A plant family of the order Solanales, subclass Asteridae. Among the most important are POTATOES; TOMATOES; CAPSICUM (green and red peppers); TOBACCO; and BELLADONNA.Ecosystem: A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)Chromosomes, Plant: Complex nucleoprotein structures which contain the genomic DNA and are part of the CELL NUCLEUS of PLANTS.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.RNA Editing: A process that changes the nucleotide sequence of mRNA from that of the DNA template encoding it. Some major classes of RNA editing are as follows: 1, the conversion of cytosine to uracil in mRNA; 2, the addition of variable number of guanines at pre-determined sites; and 3, the addition and deletion of uracils, templated by guide-RNAs (RNA, GUIDE).Hepatophyta: A plant division. They are simple plants that lack vascular tissue and possess rudimentary rootlike organs (rhizoids). Like MOSSES, liverworts have alternation of generations between haploid gamete-bearing forms (gametophytes) and diploid spore-bearing forms (sporophytes).Inflorescence: A cluster of FLOWERS (as opposed to a solitary flower) arranged on a main stem of a plant.Winteraceae: A plant family of the order Magnoliales, subclass Magnoliidae, class Magnoliopsida. The wood lacks water-conducting cells but has acrid sap. The leaves are gland-dotted, leathery, and smooth-margined. The flowers are small, in clusters, with two to six sepals, petals in two or more series, several stamens, and one to several carpels.Proteaceae: A plant family of the order Proteales, subclass Rosidae class Magnoliopsida. Cluster roots, bottlebrush-like clusters of rootlets which form in response to poor soil, are common in this family.Senecio: A species of toxic plants of the Compositae. The poisonous compounds are alkaloids which cause cattle diseases, neoplasms, and liver damage and are used to produce cancers in experimental animals.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Plant Structures: The parts of plants, including SEEDS.RNA, Ribosomal, 18S: Constituent of the 40S subunit of eukaryotic ribosomes. 18S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.Seedling: Very young plant after GERMINATION of SEEDS.Plant Roots: The usually underground portions of a plant that serve as support, store food, and through which water and mineral nutrients enter the plant. (From American Heritage Dictionary, 1982; Concise Dictionary of Biology, 1990)