Glossary Index - Click on letter

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Allopolyploid -- A polyploid of hybrid origin, in contrast to an autopolyploid resulting from the direct replication of chromosome sets; sometimes abbreviated to alloploid.

Amoena -- A name applied originally to a natural hybrid or variant of Iris variegata, now used to describe bearded irises with white standards and colored falls.

Anaphase -- The stage of nuclear and cell division during which the chromosomes separate and pass to opposite ends of the cell where they later become incorporated in the daughter cells.

Aneuploid -- Having one or a few chromosomes more or less than the balanced diploid, triploid, tetraploid or other polyploid number.

Anther -- The pollen-bearing part of the stamen.

Anthocyanin -- A blue cell-sap pigment of plants.

Apogon -- Literally, without a beard, applied to rhizomatous irises which have no beard or crest.

AriI -- The small white collar surrounding the hilium or region of attachment to the capsule of seeds of oncocyclus and regelia irises.

Arilbred -- Garden varieties combining characteristics of aril (onco and regelia) and eupogon or true bearded irises.

Asexual -- Literally, without sex; as applied to plants, propagation by subdivision of rhizomes, bulbs, or other vegetative means without the sexual union of germ cells.

Autopolyploid -- Having more than two sets of chromosomes as a result of the direct replication of chromosome sets without hybridization; sometimes abbreviated to autoploid. Back to the top

Backcross -- The cross of a hybrid to either parent.

Beard (side view) (front view)-- The conspicuous hairs borne on the center of the haft of the falls in bearded irises.

Bicolor -- A flower having standards and falls of different color, the falls usually darker than the standards as in reverse bicolors

Bitone -- A flower having standards and falls of different amounts of the same color. Ordinarily the falls are darker than the standards, but reverse bitones have darker standards.

Bivalent -- Made up of two parts, as a bivalent chromosome.

Blend -- A combination or mixture of two or more colors in the same parts of a flower.

Blending Inheritance -- Absence of dominance, the hybrid being intermediate between the parents.

Bud -- structure that contains the rudimentary inflorescence

Calyx -- The sepals or falls of the iris flower. Back to the top

Carotene -- A plastid pigment responsible for most of the yellow color of iris flowers.

Carotinoid -- Any of a class of yellow and red (lycopine) pigments found in plants.

Centromere -- The spindle attachment region of the chromosome, also called the primary constriction.

Chlorophyll -- The green coloring matter of plants.

Chromosome -- An elongate, dark-staining body in the nucleus of the cell in which the genes are arranged in linear order. The number of chromosomes is usually constant for the species or variety.

Corolla -- The showy parts of the flower between the calyx and the style -the standards (petals) of the iris flower.

Crest -- The elevated, often toothed ridge on the haft of the falls of evansia iris flowers (see also style crest).

Crossing-over -- The interchange of segments between homologous chromosomes.

Cultivar -- A cultivated variety, as distinguished from a botanical variety, which has originated or is important only in cultivation.

Cytogenetics -- A borderline field of biology concerned with the cellular (chromosomal and cytoplasmic) mechanism of heredity.

Cytology -- A branch of biology concerned with cells, their structure, function and component parts, including the chromosomes.

Diploid -- A plant or animal having two sets of chromosomes. Back to the top

Domed -- Standards of an iris flower when rounded and closed.

Dominant -- A Mendelian character which appears in a hybrid to the exclusion of the contrasted, recessive character.

Duplicate genes -- Two nonallelic genes having identical effects.

Dysploidy -- Chromosome numbers of species or other taxonomic units not in multiples of a base number. The numbers 10 and 11 of the oncos and regelias are dysploid numbers; 12, 24, 36, 48 are polyploid numbers.

Egg -- The female gamete located in the embryo sac of the ovule. Back to the top

Embryo -- The rudimentary plant within the seed, usually developed from the fertilized egg or zygote.

Endemic -- Native to a particular region, restricted in area.

Endosperm -- The part of the seed which surrounds and nourishes the embryo.

Epistasis -- The masking of one character by another (nonallelic dominance), as contrasted with hypostasis which is the failure of a character to be expressed due to the masking effect of some other character. In their relation to each other nonallelic characters may be epistatic or hypostatic, or both together may exhibit a blending effect.

Eupogon -- True bearded irises with a beard consisting of multicellular hairs in contrast to pogon (onco and regelia) irises whose beard consists of unicellular hairs.

F1 -- The first filial generation, the first generation offspring of a cross. Back to the top

F2 -- The second filial generation resulting from self-pollinating or sib-crossing the F1.

Falcate -- Sickle-shaped.

Falls --

Fertilization -- The union of the sperm and egg to form the zygote from which the embryo develops.

Filament -- The slender stalk of the stamen, terminated by the anther.

Flaring falls -- Falls held horizontally or nearly so.

Flavone -- A cell sap pigment reported to be present in certain white irises.

Floriferous -- Flower bearing, usually implying a free-blooming condition.

Form -- May refer to the shape of a flower, or to a particular kind of plant, as a color form of a species.

Gamete -- The male or female germ cell of sexually reproducing organisms. Back to the top

Gametophyte -- The generation or part of the life cycle following meiosis, which produces the gametes or germ cells, as contrasted with the sporophyte generation which begins with fertilization and ends with the formation of spores at meiosis.

Gene -- The unit of inheritance, a sub microscopic portion of the chromosome capable of controlling one or more characters.

Genetics -- The science of heredity.

Genotype -- The genetic constitution of an organism, expressed or latent, as contrasted with the phenotype or visible characteristics.

Genus -- A unit of classification consisting of one or more similar species.

Germ cell -- A cell capable of participating in the process of fertilization from which a new individual ordinarily is produced (Same as gamete).

Germplasm -- The material basis of heredity, the living substance of the cell concerned with inheritance.

Habitat -- The locality or place where a plant grows. Back to the top

Haft -- The narrow constricted part of the standards (petals) and falls (sepals) near the center of the iris flower.

Haploid -- Having the reduced or half-number of chromosomes. The body cells have the unreduced, somatic number, the gametes the haploid or reduced number.

Heredity -- The property or capability of inheriting the characteristics of parents and ancestors.

Heteroploid -- An organism having more than the basic number of chromosomes characteristic of a species or genus, either an even (polyploid) or uneven (dysploid) number.

Heterozygote -- An individual with unlike alleles.

Heterozygous -- Possessing unlike alleles, either dominant and recessive or with an intermediate effect.

Hexaploid -- A plant or animal having six sets of chromosomes.

Hilum -- The scar marking the place of attachment of the seed to the seed pod.

Homologous -- Of similar origin; with reference to chromosomes those which pair regularly and are genetically very similar.

Homozygote -- An individual with alleles which are alike.

Homozygous -- Containing but one kind of alleles.

Hybrid -- The offspring of genetically unlike parents.

Hybridization -- The crossing of two genetically different individuals.

Hypostasis -- The masking of one character by another-nonallelic recessiveness (See epistasis).

Idiogram -- A diagrammatic representation, and as used in cytology it is a representation of the chromosome complement of an individual or of a species. Back to the top

Inbred -- An individual, line or strain produced by inbreeding.

Inbreeding -- Repeated self-pollination, sib-crossing or intercrossing of closely related individuals.

Indigenous -- Native to a particular country or region.

Inhibitor -- In genetic usage a gene which inhibits the action of another gene, as the development of anthocyanin color.

Karyotype -- The sum total of the number, form and size of the chromosome complement of an individual, species or cultivated variety.

Keel -- A projecting longitudinal ridge, as the midrib of the spathe in certain iris species.

Lilliput -- A first generation iris hybrid of pumila dwarf and tetraploid tall bearded parentage. (1940s and 1950s usage. Now a SDB, Standard Dwarf Bearded) Back to the top

Linkage -- Association of characters in inheritance, due to their genes being located in the same chromosome.

Lycopene -- The pigment possibly responsible for tangerine-pink color.

Meiosis -- Two specialized cell divisions from which are derived spores and gametes with the half number of chromosomes. Back to the top

Mendelian inheritance -- Inheritance according to Mendel's laws of dominance, alternative characters and segregation and recombination.

Metacentric -- A class of chromosomes with an approximately median spindle attachment or centromere; other chromosomes have sub-terminal or nearly terminal (acrocentric) centromeres.

Metaphase -- The stage of nuclear division when the chromosomes are arranged iii an equatorial plane in preparation for the separation of their two halves (in mitosis) or their paired members (in meiosis).

MicropyIe -- The opening in the ovule leading to the embryo sac.

Microspore -- The cell resulting from the reduction divisions (meiosis) in the anther and from which the pollen grain develops.

Microsporocyte -- The cell in which meiosis is initiated and from which microspores are derived.

Mitosis -- Nuclear division in somatic tissues involving chromosome replication and the separation of the replicated chromosomes to daughter nuclei.

Monohybrid -- The offspring of parents differing in only one Mendelian character.

Multivalent -- No association of more than two chromosomes in meiosis.

Mutation -- An inherited change in the genic or chromosomal constitution of an individual.

Naturalized -- Introduced from another country and established naturally in a new environment.

Nondisjunction -- The failure of daughter chromosomes (in mitosis) or members of a pair (in meiosis) to separate, both going to the same daughter nucleus in the anaphase.

Nucellus -- The tissue of the ovule surrounding the embryo sac. Back to the top

Nucleus -- An inner part of the cell containing the chromosomes.

Oncobred -- A hybrid of oncocyclus and eupogon parentage typically showing resemblances to both parents.

Ontogeny -- The developmental history of an individual from fertilization to maturity.

Outcross -- A cross to an individual not closely related.

Ovary -- The ovule-bearing structure at the base of the flower which develops after fertilization into the seed pod containing seeds derived from the ovules.

Ovule -- The egg-containing organ within the ovary of the flower, which develops into a seed after fertilization.

Pallida -- This is the name of a European species of diploid, tall-bearded iris, I. pallida, with self-colored, lavender blue flowers borne on closely branched stems. Garden varieties with these and other characteristics of this species are described as pallida-type irises. Back to the top

Parthenogenesis -- The development of a new individual from a germ cell without fertilization.

Perennial -- Living for more than two growing seasons.

Perianth -- The collective term for the petals and sepals (standards and falls of the iris flower).

Perianth-tube -- The slender tube of the iris flower connecting the ovary with the separate perianth parts (sepals and petals).

Petal -- One of the inner series of perianth parts (one of the three standards of the iris flower).

Petiole -- The stalk of the leaf. Back to the top

pH -- A symbol used in designating acidity or alkalinity -- A pH of 7 indicates a neutral condition, lower amounts indicate acidity, higher amounts indicate alkalinity.

Phenotype -- The sum total of the expressed characters of an individual, as contrasted with its genotype or genetic constitution, which is often partly latent.

Phylogeny -- The evolutionary history of a species or other taxonomic unit.

Pistil -- The female reproductive structure of the flower, including in the case of the iris flower the ovary, style, style-branch, and stigma.

Plastid -- A minute body in the cells in which are located green and yellow coloring matter (chlorophyll, carotene, etc.).

Plicata -- A mutant form, probably of Iris pallida with white flowers edged with a plicate or stitched and dotted pattern, inherited as a simple Mendelian recessive.

Pogocyclus -- A hybrid of bearded and oncocyclus parentage, also called oncopogon.

Pogon -- A word of Greek origin meaning beard, commonly used to describe any bearded iris

Pollen -- The tiny structures, usually spherical in form or nearly so, containing the male gametes or their antecedents, which are discharged from the anther of the flower and ordinarily are borne by the wind or insects to the stigma of the ovules and there initiate fertilization.

Pollination -- The transfer of pollen from the shedding anther to the receptive stigma of the same or another flower.

Polygenic -- Controlled by several or many genes; multiple factor inheritance.

Polyploid -- Having more than two complete sets of chromosomes.

Primary constriction -- (See centromere).

Quadrivalent -- A group of four chromosomes closely associated at meiosis. Back to the top

Recessive -- A character possessed by one parent of a hybrid which may be obscured by the contrasted, allelic character contributed to the cross by the other parent. If a nonallelic character is obscured by another it is said to be hypostatic to that character (See also dominant).

Reduction divisions -- (See meiosis).

Reflexed -- Bent abruptly downward and inward; the falls may be noticeably reflexed.

Regelia bred -- An iris hybrid of regelia and eupogon parentage.

Regeliocyclus -- An iris hybrid of regelia and oncocyclus parentage.

Rhizomatous -- Producing or having a rhizome.

Rhizome -- A modified creeping or underground stem, often enlarged to serve as a storage organ, and with roots and buds developing from the nodes.

Secondary constriction -- Referring to chromosomes, the primary constriction is the centromere and any additional constriction is a secondary. Back to the top

Seed -- The ripened ovule, containing an embryo and various surrounding structures.

Self -- An iris flower with standards and falls of the same color; or self-pollination, the placing of pollen of a flower on its own stigmas.

Sepal -- A unit of the outer series of perianth parts, one of the three falls of the iris flower.

Sessile. -- Without a stem or stalk.

Sib -- Offspring from the same parents; sib-cross, a cross between plants from the same mating.

Somatic cell -- A body cell, in contrast to a germ cell or gamete.

Spathe (spathe-valve) -- A bract or modified leaf subtending a flower or group of flowers, often an inner and outer spathe are present in iris -- Spathes may be green and fleshy or dry and papery -- In early stages of development the spathes enclose and protect the young flower buds.

Sperm -- A male gamete or germ cell.

Spike -- A single, unbranched axis bearing two or more sessile flowers. Back to the top

Spores -- Cells, either microspores (male) or megaspores (female), produced as the end product of meiosis -- The microspore develops into a pollen grain containing sperms and the megaspore into an embryo sac containing an egg cell.

Sporophyte -- The generation or part of the life cycle which begins with fertilization and ends with the formation of spores at meiosis (See gametophyte).

Stamen -- The pollen-bearing structure of the flower consisting of a filament and anther containing the pollen grains.

Staminate -- Having stamens but no functional pistillate (female) parts.

Standard -- The upper usually broad more or less erect petals -- a unit of the inner series of the perianth which also includes the outer flaring or drooping falls or sepals.

Stigma -- The portion of the pistil receptive to the pollen, which in iris has the form of a ridge or lip projecting from the inner surface of the style-arm of the flower.

Style-arm -- A narrow prolongation of the ovary which bears the stigma.

Style crest -- A projection of the style-branch or style-arm.

Subspecies -- The taxonomic unit (taxon) immediately below the species; a subdivision of a species with a known and often separate distribution but not sufficiently distinct in appearance or otherwise to be classed as a species.

Sympatric -- Species growing together in the same natural habitat.

Synapsis -- Pairing of homologous chromosomes in meiosis.

Taxonomy -- The identification, classification, and nomenclature of objects. Back to the top

Testcross -- A cross to the double recessive, in contrast to a backcross which is a cross of an F1 with either parent.

Tetrad -- A group of four, as a tetrad of spores. Back to the top

Tetraploid -- A plant or animal with 4 sets of chromosomes.

Tetrasomic ratio -- A ratio involving four homologous chromosomes, as in a tetraploid plant.

Triploid -- A plant or animal whose cell nuclei contain three sets of chromosomes.

Trivalent -- A group of three chromosomes closely associated at meiosis.

Univalent -- A chromosome unpaired at meiosis.

Unreduced gametes -- Having same chromosome number as the body cells.

Variation -- The occurrence of differences among individuals of the same species, or the product of such variability. Back to the top

Variegata -- This is the name of a European species of diploid tall bearded iris, I. variegata, with yellow standards and purple falls; now being used to describe garden varieties of this color pattern.

Variety -- A cultivated plant which has been given an identifying common name (i.e. - a cultivar), or botanically, a group of individuals within a species that differ sufficiently from the rest of the species population to be distinguished and given a Latin varietal name.

Xanthophyll -- A kind of plant pigment often associated with chlorophyll and sometimes with carotene, producing yellow color.

Zygote -- The fertilized egg; also the individual developed from it. Back to the top

Common terms and part descriptions

Amoena -- A name applied originally to a natural hybrid or variant of Iris variegata, now used to describe bearded irises with white standards and colored falls.

Beard -- The conspicuous hairs borne on the center of the haft of the falls in bearded irises.

Bicolor -- A flower having standards and falls of different color, the falls usually darker than the standards as in reverse bicolors.

Bitone -- A flower having standards and falls of different amounts of the same color. Ordinarily the falls are darker than the standards, but reverse bitones have darker standards.

Cultivar -- A cultivated variety, as distinguished from a botanical variety, which has originated or is important only in cultivation.

Haft -- The narrow constricted part of the standards (petals) and falls (sepals) near the center of the iris flower.

Hybrid -- The offspring of genetically unlike parents.

Rhizome -- A modified creeping or underground stem, often enlarged to serve as a storage organ, and with roots and buds developing from the nodes.

Self -- An iris flower with standards and falls of the same color; or self-pollination, the placing of pollen of a flower on its own stigmas.

Standard -- The upper usually broad more or less erect petals -- a unit of the inner series of the perianth which also includes the outer flaring or drooping falls or sepals.