Snapshot: Glossary of bolded terms on this website.
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Credits:Funded by the National Science Foundation. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. This page includes content from the Teacher-Friendly Guide to the Evolution Maize (T. M. Fulton, C. S. Buckler, and R. A. Kissel, 2011). Additional content and revisions by Elizabeth J. Hermsen (2023).
Updates: Page last updated March 2, 2023. [Note: This page is a work in progress, and additions will be made from time to time.]
Image above: Striped kernels of corn. Photo by Petr Kratochvil (Wikimedia Commons, Creative Commons Attribution 3.0 Unported license, image resized).
abaxial: the side away from the axis. In leaves, the side of the leaf facing away the stem, or the lower side.
adaxial: the side towards the axis. In leaves, the side of the leaf facing the stem, or the upper side.
adlay: a species of grass (Coix lacryma-jobi) grown for its grains for for the hard utricles covering its grains.
adlay millet: see adlay.
adventitious root: a root that develops on a stem.
aleurone layer: in grasses, the outer layer of the endosperm, typically one cell thick, that is rich in protein and fat.
allele: alternate forms of a genetic locus. For example, at a locus determining eye color, an individual might have the allele for blue eyes, brown, etc.
allopolyploid: a condition in which diploid sets of chromosomes from different species are multiplied in an individual. See also polyploid.
alternate: describes the arrangement of structures, such as leaves, that are attached one at a time to the stem.
amber: fossilized plant resin.
amino acid: 20 molecules that are the building blocks of proteins.
amylopectin: one of two polysaccharide molecules that make up starch; unlike amylose, amylopectin is branched.
amyloplast: a double-membrane-bound structure in a plant cell in which starch is made. See also plastid.
anaerobic digestion: a process in which bacteria and/or other microorganisms decompose organic matter in an oxygen-free environment
andropogonoid grasses: grasses in Tribe Andropogoneae, commonly called the Bluestem Tribe or the Sorghum Tribe.
annual: a type of plant that completes its life cycle in a single growing season.
anther: the pollen-producing part of a stamen, which typically consists of four fused pollen sacs in two pairs; pollen develops in the pollen sacs.
antioxidant: an enzyme or other organic substance that is capable of slowing or preventing the damaging effects of oxidation – a chemical process resulting in free radicals, which cause cell-damaging reactions. Vitamin A, Vitamin E, and the carotenes are examples of antioxidants.
apical meristem: a region of dividing cells at the top of a plant organ, like a shoot or root.
apomixis: a type of asexual reproduction in which seeds are formed without the fertilization of an egg.
archaeobotany: the study of plants and their uses by humans in the archaeological record. See also paleoethnobotany.
archaeology: the study of human cultures of the past.
arepa: a fried cake made from maize flour that is part of the traditional cuisine of some Latin American countries.
artificial selection: human-mediated selective breeding of organisms in order to modify the traits of their offspring over generations.
asexual reproduction: reproduction without meiosis and fertilization.
auricle: on a grass leaf, projections at the base of the blade.
autopolyploid: a condition in which a set of chromosomes from the same species is multiplied in an individual. See also polyploid, compare to allopolyploid.
awn: an extension of tip of a bract in a grass plant.
axil: the upper angle between the base of a leaf and a stem.
axillary bud: a bud that forms in the axil of a leaf.
bagasse: material remaining after sugarcane juice has been extracted from the stalks.
Balsas teosinte: Zea mays subspecies parviglumis, the ancestor and most closely related plant to modern maize (Zea mays subspecies mays).
barley: species of domesticated cereals and their wild relatives in the genus Hordeum.
base: one of the four nitrogenous subunits (nucleotides) of DNA: adenine (abbreviated as A), guanine (G), cytosine (C), and thymine (T). In the DNA molecule, they are linked to one another in pairs of long chains, where each member of the pair is complementary to the other. This double-stranded chain is itself twisted into a double helix. The complementarity between the strands is brought about by the interaction between A and T, and between G and C. Since the identity of a base on one strand can be used to infer the identity of the corresponding base on the other strand, the terms “base” and “base pair” are often used interchangeably. The number of bases (or base pairs) is used as a measurement of the size of a genome. For example, the length of the human genome is approximately 3 billion base pairs (abbreviated bp).
beer: in the production of biofuels, fermented liquid containing a relatively low concentration of alcohol.
beriberi: a disease caused by malnutrition, specifically lack of sufficient dietary thiamine. Beriberi is classified as wet or dry. Wet berberi is characterized by edema (swelling) caused by cardiovascular problems. Dry beriberi is characterized by nerve damage that can progress to paralysis.
biennial: a type of plant that completes its life cycle in two growing seasons.
billet: a piece of a sugarcane stem with one or more buds that is planted to grow a new sugarcane crop. See also sett.
biodiesel: diesel fuel made from animal fats, plant oils, or spent cooking oil.
bioethanol: ethanol (ethyl alcohol) made by fermenting plant matter, then distilling it to concentrate the alcohol by separating it from water.
biofuel: fuel that is derived from a living or recently living organism, as opposed to fossil fuels, which are produced from the altered remains of long-dead animals.
biogas: a type of gas made by anaerobic digestion of organic matter that consists mostly of carbon dioxide and methane, along with contaminants.
biomethane: methane (CH4) made by purifying biogas, which ultimately comes from anaerobic digestion of organic matter.
bisexual: of flowers or florets, a flower or floret with both stamens and carpels/pistils; a flower that produces both pollen and ovules; a flower that has both male and female structures.
blade: the flat portion of a leaf that intercepts sunlight; in grasses, the portion of the leaf that protrudes away from the stem.
blister stage: a stage in development of maize ears when fertilized ovules (developing kernels) are white and blister-like and the cob can be seen between the kernel rows.
boot stage: the stage in development of a grass plant when the inflorescence begins to emerge from the flag leaf.
bourbon: a type of whiskey made using at least 51% maize grain.
brace root: a root that originates on an above ground part of a plant and grows into the soil; helps to support the plant. See also prop root.
bran: the outer layer of a cereal or grass grain, including the fruit wall, seed coat, and aleurone layer.
broomcorn: a type of sorghum cultivated for its branches, which are used as natural broom bristles or for decorative purposes.
brown sugar: refined or white sugar with added molasses, giving it a brown color and distinct flavor. Not to be confused with raw sugar.
bud: an immature flower or an immature branch.
bulbil: an asexual reproductive structure capable of growing into new plant.
bulliform cells: rows of large cells in the epidermis of a grass leaf that serve to fold the leaf when it is desiccated.
bundle cap: a group of fibers (elongated, thick-walled cells) next to a vascular bundle.
bundle sheath: a layer or two layers of cells that encircle a vascular bundle in a leaf.
cane: the robust stem of a tall grass, like sugarcane or sweet sorghum.
cane syrup: sugary syrup made by heating the juice extracted from sugarcane stems to evaporate part of the liquid.
carbohydrate: molecules produced by plants that contain carbon, hydrogen, and oxygen. Usually, these elements are in the following ratio: Cm(H2O)n.
carbon-fixing reactions: photosynthetic reactions that convert carbon dioxide to sugars.
carotenoid: organic pigments occurring in plants, such as carotene, many of which can be converted to Vitamin A in humans. These pigments are typically red, orange, or yellow in color.
carpellate: a flower with carpels but no stamens; a female flower. See also pistillate.
caryopsis: a type of fruit containing a single seed in which the seed coat is completely fused to the fruit wall. See also grain.
cellulosic ethanol: bioethanol made from the cellulose contained in vegetative plant parts, like leaves, stalks, or wood.
central cavity: a depression around the hilum in a starch grain.
central cell: the large cell in the center of the embryo sac. Typically contains two haploid nuclei.
centrifugals: machines that spin massecuite in order to separate the sugar crystals from the molasses.
centromere: the constricted region on a chromosome. The centromere is the region at which the two strands (chromatids) of a chromosome are joined when it has duplicated.
cereal: an edible grain from a grass, or a grass that is grown for its edible grain.
chaff: the bracts surrounding the grain in a cereal.
chicha: a fermented alcoholic beverage made from maize kernels.
Chinese pearl barley: see adlay.
chloroplast: a double-membrane-bound organelle that contains the green pigment chlorophyll and is involved in photosynthesis. See also plastid.
chorreada: a type of maize pancake that is part of the cuisine of Costa Rica.
chromatid: when a chromosome has duplicated, one of the two DNA strands joined at the centromere.
chromosome: the structure in the eukaryotic nucleus and in the prokaryotic cell that carries most of the DNA.
citronella: name sometimes used for Cymbopogon species used to produce citronella oil, particularly Ceylon citronella (Cymbopogon nardus) and Java citronella (Cymbopogon winterianus).
citronella grass: see citronella.
clade: a group of organisms (typically, species) made up of an ancestor and all of its descendants.
clarified juice: sugarcane juice that has had impurities removed.
cob: the central axis (stem) of an ear of maize.
coix: see adlay.
coleoptile: a sheath covering the plumule (embryonic shoot) in the grass embryo.
coleorhiza: a sheath covering the radicle (embryonic root) in the grass embryo.
collar: on a grass leaf, the junction of the sheath and blade.
common name: a non-scientific name for a group of organisms (typically, equivalent to a genus or species) in any language. For example, "wheat" is the English common name for grasses in the genus Triticum.
confectioner's sugar: see powdered sugar.
coprolite: fossilized feces.
cork cells: short cells in the epidermis of grasses that accumulate suberin (cork).
corn: maize; in some areas of the world, refers more generally to grain.
corn oil: oil derived from maize kernels.
corn syrup: a sugary syrup made by breaking down the starch stored in kernels of maize to yield glucose.
cornbread: bread made from maize flour or cornmeal.
cornstarch: starch derived from corn kernels.
cortex: the region of a stem or root beneath the epidermis and outside of the vascular bundles.
cotyledon: a seed leaf; a non-foliage leaf that is part of a plant embryo and that may store food or transfer stored food to the embryo. See also scutellum.
crop improvement: the modification of crops using traditional or laboratory techniques in order to create crops with desirable traits.
crossing over: an event during the early stage of meiosis when homologous (equivalent) chromosomes swap equivalent segments of DNA. See also recombination.
cross pollination: type of pollination where pollen from one plant lands on or is transferred to the stigma of another plant.
crown: base of a grass plant at ground level.
culm: the upright or aerial stem of a grass.
cultivar: a group of cultivated plants that is defined by a unique feature or set of features that are consistently present if the plants are propagated correctly.
cytogenetics: the study of chromosome shape and function.
degerminated: in maize, removing the bran and germ from the kernels.
dent corn: a variety of maize with kernels that have equal parts hard and soft starch; each kernel has a large dent in its apex (tip) at maturity.
dent stage: the stage in maize kernel development when a dent forms in the top of the kernel as the amount of moisture in the kernel decreases.
digestate: one of the products of the anaerobic digestion process used to make biogas.
dioecious: a plant that has only male or female parts (and therefore cannot self-fertilize).
diploid: having two sets of chromosomes per cell. Often denoted using as "2n."
disaccharide: two-unit saccharide often called a sugar. An example is sucrose.
disseminule: the reproductive dispersal unit of a plant, like seed or fruit.
distichous: describes the arrangement of structures, such as leaves, that are attached to the stem in two ranks (in other words, structures that are in two rows on the stem).
distillation: a process used to separate liquids (like alcohol and water) that have different boiling points; in distillation, the liquid that boils at a lower temperature is converted to vapor, captured, and condensed (cooled so that it changes to liquid once again).
distillers grain: waste product remaining after grain ethanol is distilled during the process of making spirits (distilled alcoholic beverages) or biofuels; used to make animal feed.
DNA: an abbreviation for “deoxyribonucleic acid”, the carrier molecule of genetic information. The chain of nucleotides is held together on a polymer backbone formed by a sugar (deoxyribose) and a phosphate group (see also base).
DNA sequence: the specific order of the nucleotide bases that make up DNA See also DNA and base.
domestication: the process by which plants and animals are genetically modified over time by humans for traits that are more advantageous for humans.
dominant: as refers to gene action, the allele that masks the effect of another allele when present in a heterozygote state.
dormancy: describes a state in which a seed cannot germinate; dormancy must be broken (for example, by exposure to cold) before germination can occur.
double fertilization: in flowering plants, a process in which one sperm in a pollen grain unites with an egg to form a zygote and the other sperm in a pollen grain unites with the nuclei in the central cell to form the primary endosperm nucleus, the first cell of the endosperm.
dough stage: a stage in grain development when moisture decreases, starch increases, and the inside of the grain is dough-like.
ear: a grass inflorescence; used especially to describe the inflorescences of cultivated grasses.
egg: a female sex cell; typically, eggs are the larger of the two types of reproductive cells and are nonmotile (do not swim).
element: an atom that is defined by the number of protons in its nucleus.
embryo: in flowering plants, an immature stage of plant development that occurs in the seed.
embryo sac: a tiny, egg-bearing structure in flowering plants. In flowering plants (like grasses), one embryo sac develops per ovule; at maturity, each embryo sac consists of a small number of cells, including one egg. The embryo is also known as the megagametophyte or female gametophyte (gamete-bearing plant).
emergence: the stage in the development of a grass plant when the coleoptile emerges above the surface of the ground.
endosperm: a specialized food tissue found in the seeds of flowering plants.
enriched: food product with added nutrients. See also fortified.
epidermis: the outer tissue of the plant body, typically one cell thick.
essential oil: plant oils containing volatile compounds that give them a distinct aroma.
ethanol: a type of alcohol.
extinction cross: a dark cross that can be seen on a starch grain when it is viewed under cross-polarized light.
fermentation: the process in which yeast converts sugar in ethanol (ethyl alcohol).
fertilization: the union of male and female gametes (sperm and egg) to form a zygote.
fiber: 1) plant anatomy: elongated, thick-walled cell that is typically dead at maturity and that provides support in the plant body. 2) nutrition: cellulose, a type of carbohydrate that makes up the cell wall of plants.
fibrous root system: a root system made up of similarly sized adventitious roots.
field corn: see dent corn.
filament: the stalk of a stamen.
flag leaf: the highest foliage leaf on a cereal plant, located below the terminal inflorescence.
flint corn: corn that may have kernels in a variety of colors, including on the same cob; the kernels have a hard outer wall.
floret: the highly modified flower and associated structures in grasses. Including the reproductive structures (anthers, pistil), lodicules, palea, and lemma.
flour corn: corn with soft kernels that have mostly soft starch (floury endosperm).
floury endosperm: soft, white, opaque endosperm.
fodder: food for livestock.
form: a taxon below the rank of variety.
fortified: food product with added nutrients. See also enriched.
fossil fuel: a fuel made from products that come from the remains of long-dead organisms, like gasoline, oil, and diesel fuel.
free-threshing: a grain with bracts that are delicate and weakly attached, and thus relatively easy to remove.
fructose: a monosaccharide (sugar) found in fruits, honey, and vegetables. Chemical formula C6H12O6. Has the same formula as glucose, but a different molecular structure. Sweeter in flavor than glucose and sucrose.
fruit: the mature ovary of a flower that contains the seeds.
fruitcase: a hard wall (case) the covers the fruit of teosinte and is made up of the hardened glumes and a segment of the rame axis (inflorescence branch).
functional mutation: a mutation that causes a change in an organism.
gamete: a mature sex cell, as a sperm or egg, that unites with another cell during fertilization.
gene: a unit of heredity, transmitted from generation to generation during reproduction. Each gene consists of a sequence of nucleotides, occupying a specific position along a chromosome. Most genes encodes a specific functional product.
gene mapping: determining the location of specific genes or DNA segments on a chromosome.
genetic diversity: the differences among organisms at the gene or DNA level.
genetic engineering: the process of altering the DNA of an organism in a lab.
genetically modified organism: a genetically engineered organism, usually specifically a transgenic organism. Also called a GMO.
genome: all the genetic material of an organism.
genotype: the inherited genetic constitution of an organism.
genus: a formally named group of species that are more closely related to one another than they are to species in any other genus.
germ: the embryo of a cereal or grass grain.
germination: resumption of growth following formation of the seed.
germplasm: seeds or other material from which plants can be propagated; the collection of a set of genetic resources for an organism, which for plants can consist of a seed collection or plant nursery.
glucose: a monosaccharide (sugar), chemical formula C6H12O6. Has the same formula as fructose, but a different molecular structure.
glume: a bract at the base of a grass spikelet, below the florets.
glutinous corn: see waxy corn.
GMO: see genetically modified organism.
grain: a type of fruit containing a single seed in which the seed coat is completely fused to the fruit wall. See also caryopsis.
grits: coarse-ground, cooked maize that is a traditional food in North America, particularly the southeastern United States.
ground tissue: plant tissue that is found beneath the epidermis and around the vascular tissue; makes up cortex, pith, and mesophyll.
growing point differentiation: the stage in the development of a sorghum plant when the shoot apical meristem switches from initiating new leaves to forming the reproductive structures.
guard cell: a cell that borders a stoma (pore) in the epidermis and controls whether it is opened or closed.
haploid: having one set of chromosomes per cell. Often denoted using the letter "n."
hard-dough stage: stage of grain development when the interior has the consistency of hard dough.
head: term for a dense terminal infloresence, like the head of grain on a sorghum plant.
herb: a plant containing essential oil in its tissue that is used as a flavoring ingredient for food. Herbs are often from leaves and herbaceous (non-woody) stems.
heterosis: progeny that are bigger and healthier than either of their parents as a result of the cross-breeding of genetically different parents (the opposite of inbreeding depression). See also hybrid vigor.
heterozygous: having different alleles at a particular locus of the genome. In a diploid organism, inheriting different alleles for a gene from each parent.
hexaploid: having six sets of chromosomes per cell.
HFCS: see high fructose corn syrup.
HFCS 42: type of high fructose corn syrup containing 42% fructose sugar.
HFCS 55: type of high fructose corn syrup containing 55% fructose sugar.
high fructose corn syrup: a sugary syrup made by breaking down the starch stored in kernels of maize, then converting some of the glucose to fructose.
hilum: in starch grains, a central point around which a starch grain accumulates; in seeds or fruits, the scar that marks the attachment point of the seed or fruit to a stalk.
hominy: nixtamalized maize kernels.
homozygous: having the same alleles at a particular locus of the genome. In a diploid organism, inheriting the same allele for a gene from each parent.
horny endosperm: see vitreous endosperm.
hull: the hard bracts surrounding a grain.
hulled: a grain in which the hard bracts are not removed by threshing, but are removed through additional techniques like pounding; grains that are not free-threshing.
hulling: removing the hull from a grain.
husk: in maize, a series of modified leaves that encloses the ear.
husking: removing the hull from a grain, or removing the leaves that surround an ear of maize.
homologous chromosomes: equivalent chromosomes. In a diploid organism, the equivalent chromosome inherited from each parent. For example, chromosome 15 from an individual's mother is homologous with chromosome 15 inherited from an individual's father.
homozygous: contains identical alleles at a particular locus of the genome.
horny endosperm: the hard endosperm in some grains.
hybrid: a cross between two or more plant lineages, such as two genera, two species, or even two different pure-breeding lines of plants in the same species.
hybrid formula: a way of writing the name of a hybrid in which the names of the two parent taxa are listed alphabetically separated by a multiplication sign.
hybrid vigor: progeny that are bigger and healthier than either of their parents as a result of the cross-breeding of genetically different parents (the opposite of inbreeding depression). See also heterosis.
hypocotyl: the portion of a grass embryo between the attachment point of the cotyledon (scutellum) and the radicle (embryonic root).
hypsodont: adjective describing high-crowned teeth, like those of modern horses.
inbreeding: self-pollination and self-fertilization by the same individual, or cross-breeding between genetically similar parents.
inbreeding depression: the loss of health or vigor resulting from the cross-breeding of genetically similar parents.
Indian corn: see flint corn.
inflorescence: a group of flowers.
infraspecific epithet: the epithet (one-word part of a multipart name) given to a taxon below the rank of species, such as subspecies, variety, or form.
infraspecific taxon: any named group of organisms below the rank of species.
inheritance: the set of genetic characteristics passed on from parents to progeny.
integument: the outer one or two layers of the ovule that form the seed coat in the seed.
internode: a region of the stem between two successive nodes.
interstomatal cell: a long cell in the epidermis of a grass that borders a stoma on its short side.
invert syrup: a syrup made by mixing white sugar with water and an acid, and heating. The acid breaks down the sucrose molecules in sugar into fructose and glucose molecules.
isotopes: forms of an element with different numbers of neutrons.
Job's tears: see adlay.
jointed stem: a stem with swollen nodes.
kernel: a maize grain.
Kranz anatomy: a type of leaf anatomy in which mesophyll is arranged concentrically around a bundle sheath.
lamellae: layers; growth layers, for example.
landrace: a variety of domesticated plant that was or is cultivated in a specific region and that developed through local, traditional farming practices. Landraces are typically more variable in their characteristics than modern cultivars.
Laws of Inheritance: three laws that describe how traits are inherited from parent to offspring. These laws were devised by Gregor Mendel in 1866 based on experiments with pea plants. The laws are the Law of Segregation, the Law of Independent Assortment, and the Law of Dominance.
leaf: the photosynthetic organ of a plant that is borne laterally on the stem in a regular pattern (for example, alternative, opposite, etc.).
leaf primordium: an immature leaf that is developing at the edge of a shoot apex.
lemma: the lower bract of a grass floret.
lemongrass: species of Cymbopogon used as herbs and sources of lemongrass oil, especially West Indian lemongrass (Cymbopogon citratus), East Indian lemongrass (Cymbopogon flexuosus), and Jammu lemongrass (Cymbopgon pendulus).
light reactions: photosynthetic reactions that must take place in the presence of sunlight.
ligule: a membrane or row of hairs on the inner side of a grass leaf at the junction of the sheath and blade.
linkage: of genes, genes that are near one another on the same chromosome and therefore tend to be inherited together.
locus: the position of a gene or mutation on a chromosome.
lodging: a word describing a situation in which the stems of grass plants become permanently bent or matted. In domesticated plants, lodging makes harvesting of grain difficult.
lodicules: small bumps or swellings at the base of a grass flower; lodicules expand to open the floret.
long cell: elongated cell in the epidermis of a grass leaf that may have sinuous side walls.
macrofossil: a fossil that is large enough to see without the use of a microscope.
maize: Zea mays subspecies mays, a cereal that originated in and was domesticated in Mexico. See also corn.
mano: a handheld stone used for grinding maize or other plant material.
mapping genes: see gene mapping.
masa: dough made from ground, nixtamalized maize. Masa is used in many traditional Mesoamerican foods, like gorditas and tortillas.
masarepa: a precooked maize flour used to make arepas.
massecuite: crystalized sugar in liquid formed during the process of sugar milling. Massecuite is centrifuged to separate the sugar crystals from the liquid during the production of sugar.
megaspore: in plants with two size classes of spores, the larger spores. In flowering plants, megaspores develop into embryo sacs.
meiosis: part of the sexual reproduction process where cell division occurs such that the diploid chromosome number is reduced to form haploid gametes or haploid spores.
meristem: a region of dividing cells that have not yet fully differentiated (taken on a mature identity).
mesocotyl: the portion of a grass embryo between the attachment point of the cotyledon (scutellum) and the plumule.
mesophyll: the tissue in a leaf within the epidermis and around the veins. Includes cells with chloroplasts that carry out photosynthesis.
mestome sheath: in a two-layered grass bundle sheath, the inner ring of cells that have walls containing suberin.
metate: a stone with a depression in it used for grinding maize or other plant material.
Mexican teosinte: Zea mays subspecies mexicana, a plant closely related to modern maize (Zea mays subspecies mays).
microfossil: a tiny fossil that must be examined using a microscope.
micropyle: an opening in the integument(s) of the ovule. Typically, the pollen tube enters the ovule through the micropyle.
microspore: in plants with two size classes of spores, the smaller spores. In flowering plants, microspores develop into pollen grains.
midvein: the central vein of a leaf.
milk stage: a stage in grain development when a grain has the highest amount of sugar and contains milky juices.
millet: small-grained grasses grown as cereals and belonging to a variety of species mostly from the Millet Tribe (Tribe Paniceae).
milling: in cereals, processing grain by polishing or grinding. In sugarcane, processing sugarcane to extract the juice and convert it into sugar.
mobile genetic element: a gene or segment of DNA that moves to a different location in the genome. See also transposon.
molasses: brown, viscous liquid that is separated from crystalline sugar during sugarcane production. In modern sugar milling and refining, molasses are separated from sugar crystals by centrifuging.
monoculture: a term describing a situation in which one species or one variety of plant is overwhelming dominant. The term can be applied to natural habitats or to cultivated crops.
monoecious: in flowering plants (like grasses), a plant that has separate male and female flowers, but with both types of flowers occurring on the same plant. Compare to dioecious.
monosaccharide: one-unit saccharide often called a sugar. Examples are fructose and glucose.
mud: in the context of sugarcane milling, solid waste formed during clarification of sugarcane juice.
mutation: a change to one or more nucleotides in a DNA sequence; an abrupt change in the genotype of an organism that is not the result of recombination.
neutral mutation: a mutation that does not cause a change in an organism.
neutron: a particle in the nucleus of an atom that has no charge.
nixtamalization: the process of steeping maize (corn) kernels in limewater (water mixed with calcium hydroxide).
noble cane: domesticated sugarcane of the species Saccharum officianarum with stems that are high in sucrose.
nodal roots: roots that form on the nodes of a grass stem (stalk)
node: the place on a stem where a leaf is produced.
non-centrifugal sugar: a type of sugar that is not refined, or not centrifuged to remove the molasses. Typically produced by heating sugarcane juice and then cooling the resulting thick syrup in a mold. Brown in color. Called gur, jaggery, kokuta, panelo, piloncillo, rapadura, and other names.
non-coding DNA: regions of an organism's DNA sequence that is not translated into genes.
non-shattering: in grasses, typically refers to an inflorescence that does not disarticulate or break apart when mature. Non-shattering inflorescences are associated with domestication.
nothogenus: the name of a hybrid genus that is made by combining the names of its parent genera into a single word.
nothospecies: the name of a hybrid species that is made by using a unique species epithet preceded by a multiplication sign.
nucellus: in flowering plants, the layer of the ovule within the integuments that surrounds the embryo sac; the tissue in which the embryo sac develops within the ovule.
nucleotide: the unit of DNA, consisting of one base, one phosphate molecule, and the sugar deoxyribose. See also base.
nucleotide base: the unit of DNA, consisting of one base, one phosphate molecule, and the sugar deoxyribose. See also base.
nucleus: a membrane-bound structure that contains chromosomes in a cell; often called the "control center" of the cell.
oats: species of domesticated cereals and their wild relatives in the genus Avena.
octoploid: having eight sets of chromsomes per cell.
oil: thick, liquid substance made up of fatty acids and glycerol produced by plants and animals; in human nutrition, a source of dietary lipids.
open: of a leaf sheath, describing a sheath with overlapping edges that are not fused.
outcrossing: a type of cross pollination when pollen from one plant lands on or is transferred to the stigma of a genetically different plant.
ovary: the ovule-containing part of a pistil/carpel in a flower.
ovule: an immature seed. In flowering plants, the ovule consists of an embryo sac surrounded by a layer of tissue known as the nucellus, which is in turn surrounded by one to two layers of tissue known as integuments.
palea: the upper bract of a grass floret.
paleobotany: the subdivision of paleontology that uses the fossil record to study the evolution of plant life through time.
paleoethnobotany: the study of plants and their uses by humans in the archaeological record. See also archaeobotany.
paleontology: the study of ancient life through examination of the fossil record.
paleosol: an ancient soil.
palmarosa: Cymbopogon martini var. motia, a species of grass that produces essential oil containing geraniol, which is considered to have a scent similar to roses (Rosa).
palynologist: a scientist who studies pollen, spores, and other small structures.
panicle: a type of inflorescence with a central rachis (branch) bearing lateral branches.
panicle initiation:the stage in the development of a sorghum plant when the shoot apical meristem switches from initiating new leaves to forming the reproductive structures.
parenchyma cell: cell type that is typically thin-walled and living at maturity. Parenchyma cells play a variety of roles in the plant body.
parenchymatous sheath: in a two-layered grass bundle sheath, the outer ring of cells.
parthenocarpic: a fruit that can develop and ripen without fertilization of the ovules inside.
pathogen: a disease-causing agent (e.g. bacteria, virus, insect, etc.).
PCR: abbreviation for “polymerase chain reaction”, the process by which a defined fragment of DNA is replicated in vitro in a so-called thermocycler or PCR machine. It provides a quick, inexpensive way of making a large number (millions) of copies of a specific DNA segment.
pedicel: the stalk of a single flower in an inflorescence; in grasses, the stalk of a spikelet.
pedicellate: typically, a flower in an inflorescence that has a stalk; in grasses, often used to described a spikelet that has a stalk.
peduncle: the stalk of an infloresence (group of flowers).
pellagra: a disease caused by malnutrition, specifically lack of sufficient dietary niacin. Symptoms include diarrhea, rashes on exposed areas of the body like the hands and upper chest, dementia, and death.
perennial: a type of plant that may live for an indefinite number of years.
pericarp: fruit wall.
phenotype: the visible appearance of an organism. The phenotype reflects the combined action of the genotype and the environment where the individual exists.
phloem: the food-conducting tissue in vascular plants.
phyllotaxy: the arrangement of leaves on a stem.
physiological maturity: a stage in grain development when a grain has reached its maximum weight and has stopped growing. May be indicated by the formation of a layer of black tissue at the base of the grain.
phytolith: a silica body that is produced within the cell of a plant.
piki: a Hopi flatbread made from maize flour, ash, and water.
pistil: the ovule-containing structure in a flower. Typically consists of a stigma, a style, and an ovary. Sometimes called the female part of the flower.
pistillate: a flower with a pistil but no stamens. A female flower.
pith: region of ground tissue in the center of a stem or root.
plant breeding: the purposeful selection, growth, and pollination of particular plants.
plastid: a double-membrane bound structure in a plant cell that is descended from a cyanobacterium (blue-green alga) and plays various roles, for example in photosynthesis and starch synthesis. Each plastid contains a circular chromosome like a bacterium.
ploidy: the number of complete sets of chromosomes in each cell in an organism. The ploidy series is haploid (1 copy), diploid (2 copies), triploid (3 copies), tetraploid (4 copies), pentaploid (5 copies), hexaploid (6 copies) etc. See also polyploidy.
plumule: in a grass embryo, the portion of the embryo bearing the shoot apical meristem and young foliage leaves; portion of the embryo above the mesocotyl.
pod corn: corn with kernels that are covered by long glumes.
pollen grain: a tiny, sperm-bearing structure in seed plants. In flowering plants (like grasses), pollen grains form in the anthers of the flower; at maturity, each pollen grain consists of two sperm and a tube cell or vegetative cell enclosed in a resistant wall. The pollen grain is also known as the microgametophyte or male gametophyte (gamete-bearing plant).
pollen: the collective name for pollen grains.
pollen tube: in flowering plants, a tube-like structure that is formed by growth of the tube cell in the pollen grain after it lands on a stigma. The pollen tube delivers the sperm to the embryo sac.
pollination: in flowering plants, the transport of a pollen grain from an anther to a stigma.
polyploidy: a state in which more than two copies of a complete genome are present. Polyploidy is rare in animals, but common in plants. In animals (and also plants) some tissues within a diploid organism can be polyploid. See also ploidy.
popcorn: a variety of maize with small kernels that have a hard outer wall and soft starch; when heated, the starch in the kernel explodes, yielding a fluffy white kernel.
powdered sugar: refined or white sugar mixed with cornstarch.
primary root: root that forms from the radicle (embryonic root).
progenitor: parent, ancestor, predecessor.
progeny: offspring, children.
prop root: a root that originates on an above ground part of a plant and grows into the soil; helps to support the plant. See also brace root.
protein: a molecule made up of amino acids that is found in some animal and plant tissues.
proton: a positively charged particle in the nucleus of an atom.
quantitative trait: a trait or characteristic that cannot be accounted for by only one gene but rather is governed by several or many genes working together.
rachilla: the central axis of a spikelet to which the florets are attached.
rachis: in grasses, the central axis of an inflorescence.
radicle: the embryonic root.
radioactive isotope: an isotope that is unstable and will undergo radioactive decay.
rame: an inflorescence branch that typically bears spikelets in pairs and disarticulates (breaks apart) at maturity. Characteristic of Tribe Andropogoneae in the grass family (Poaceae).
ratoon: a sugarcane crop grown from plants that regenerate after the sugarcane has been harvested at least once.
raw sugar: brownish crystalline sugar produce by extracting, filtering, clarifying, crystallizing, centrifuging, and drying sugarcane juice. Often considered non-food-grade, this sugar is typically processed further to create refined white sugar.
recessive: an allele that can be masked by an alternative allele in the heterozygous state. The phenotype of a recessive allele may only be expressed in the homozygote state.
recombination: an event during the early stage of meiosis when homologous (equivalent) chromosomes swap equivalent segments of DNA. See also crossing over.
refined: in cereals or grains, removing the bran and germ to leave the starchy endosperm behind.
refined sugar: sugar made up of large, regular, white crystals. Contrast to raw sugar.
refining: the process of producing refined grains or refined sugar.
rhizome: a stem that grows horizontally below ground.
rice: species of domesticated plants and their wild relatives in the genus Oryza. See also wild rice.
root: the anchoring and absorptive organ of a plant that typically occurs below ground.
root apical meristem: region of dividing cells at the tip of a root.
rotary quern: a device for grinding grain that consists of two flat, round stones sitting one atop the other. The upper stone has a hole in the center and a divot at the edge. Grain is poured into the center of the upper stone and a pole is placed in the divot and used to turn the upper stone, grinding the grain between the two stones.
rum: a type of distilled spirits made from fermented sugarcane juice or molasses.
rye: species of domesticated cereals and their wild relatives in the genus Secale.
saccharide: see carbohydrate.
scientific name: a name given to a species following a formal set of rules. A scientific name for a species has two parts (a genus name and a specific epithet), is always written using the Latin alphabet, and typically takes the form of a Latin word.
scutellum: the cotyledon in a grass seed; a structure that absorbs food and transfers it to the embryo when it resumes growth.
seed: a mature ovule in a seed plant. Contains a plant embryo and food for the embryo and is covered by a seed coat.
seed dormancy: a condition that prevents seeds from germinating until it is removed.
seeding: in the context of sugar milling, adding sugar crystals to sucrose-containing liquid to help initiate the process of sucrose crystallization.
self pollination: type of pollination where pollen from a plant lands on or is transferred to the stigma of the same plant.
selfing: self pollination and self fertilization.
seminal roots: roots that form on the grass embryo above the radicle (for example, on the hypocotyl or mesocotyl).
sessile: lacking a stalk.
sett: a piece of a sugarcane stem with one or more buds that is planted to grow a new sugarcane crop. See also billet.
sexual reproduction: a type of reproduction involving meiosis and fertilization.
shattering: a form of seed dispersal in which plant structures fall apart. In grasses, typically refers to the disarticulation or breaking apart of the inflorescence. Shattering is necessary for plants in the wild, but disadvantageous for harvesting (the seeds fall to the ground and are more difficult to harvest).
sheath: the lower portion of a grass leaf that surrounds the stem.
shelling: removing maize kernels form the cob.
shoot apical meristem: region of dividing cells at the tip of a shoot.
short cell: short cell in grass epidermis that accumulates silica or cork.
silica cell: short cell in the epidermis of a grass that accumulates silica.
silk: the long stigma of maize.
silking: the stage of development when maize ears produce silks.
simple syrup: a syrup made by mixing white sugar with water and heating.
SNP: an abbreviation for “single nucleotide polymorphism”, pronounced "snip". A SNP that distinguishes two sequences can be used as a genetic marker.
sofkee: a soup made from maize kernels and wood ash that may also be fermented; a traditional dish of the Native Peoples of the southeastern United States.
soft-dough stage: stage of grain development when the interior has the consistency of soft dough.
sorgo: see sweet sorghum.
sorghum: cultivated plants in the species Sorghum bicolor.
sorghum molasses: see sorghum syrup.
sorghum rum: a distilled alcoholic beverage made from fermented juice extracted from the stalks of sweet sorghum plants.
sorghum syrup: sucrose-containing syrup made from juice extracted from stems of sweet sorghum.
species: a population of organisms that is capable of interbreeding and producing fertile offspring.
specific epithet: the second word that makes up a two-world species name in the scientific system for naming organisms.
sperm: a male sex cell. Typically, sperm are the smaller of the two types of reproductive cells and are motile (swim), although in flowering plants they are nonmotile (do not swim) and are delivered to the egg by a pollen tube.
spike: an inflorescence in which the flowers are sessile (lack stalks).
spikelet: a unit of the inflorescence in grasses that includes one or more florets, typically above two glumes (bracts).
spore: a reproductive cell that can grow into an organism without fusing with another cell. Some plants, like ferns, are free-sporing (release their spores), whereas other plants, like flowering plants, are not. In flowering plants, the spores develop into pollen grains that contain the sperm and embryo sacs that contain the eggs.
sporopollenin: the hard substance that makes up the walls of pollen grains and spores in plants.
stable isotopes: isotopes that do not undergo radioactive decay.
stamen: the pollen-producing structure of a flower. Typically consists of a filament (stalk) and an anther made up of fused pollen sacs in which the pollen develops. Sometimes called the male part of the flower.
staminate: a flower with stamens but no pistil (carpels). A male flower.
starch: a polysaccharide, also called a complex carbohydrate.
stem: the axis of a plant that bears the leaves and the structures involved in sexual reproduction, like flowers. Stems are typically considered aboveground structures (although some types of stems do grow below ground).
sterile: of flowers, having neither functional stamens nor pistils/carpels; producing neither pollen nor ovules.
stigma: the part of a pistil/carpel that receives the pollen.
stillage: waste product remaining after maize ethanol is distilled; used to make animal feed.
stolon: a horizontally growing, aboveground stem, especially one that produces plantlets at the nodes.
stoma (plural, stomata or stomates): a pore in the epidermis of a leaf or stem that serves as a site of gas exchange.
stomatal appartus: the specialized cells surrounding a stoma (a pore in the epidermis of a leaf or stem), including guard cells and subsidiary cells.
stover: the leaves and stalks of maize or other grain plants.
straw: in cereals, the vegetative parts of the plant, particularly the stem and leaves.
stubble crop: see ratoon.
style: the stalk-like portion of a pistil/carpel that connects the ovary and the stigma.
suberin: a fatty compound that accumulates in the walls of some plant cells and prevents the movement of substances through the cell walls.
subsidiary cell: a cell in the epidermis flanking a guard cell that is distinct from the surrounding epidermal cells.
subspecies: a taxon below the rank of species and above the rank of variety.
succotash: a stew made with maize and other ingredients, traditionally prepared by Native Peoples in the northeastern United States.
sucrose: a disaccharide made up of fructose and glucose molecules bonded together, chemical formula C12H22O11.
sugar: typically, sucrose, a disaccharide made up of fructose and glucose; also called white sugar, table sugar, or refined sugar. More generally, monosaccharides or disaccharides.
sugarcane: various species of wild and domesticated tropical grasses in the genus Saccharum. Domesticated forms are mostly cultivated for the sugary juice in their stems.
sweet corn: a type of maize with kernels that have a relatively high amount of sugar, giving them a sweet flavor; this type of maize is the type that is often eaten fresh off the cob.
sweet sorghum: a variety of domesticated sorghum (Sorghum bicolor subspecies sorghum) that accumulated sucrose in its stem.
table sugar: see refined sugar.
tassel: in maize and teosinte (plants in the genus Zea), the staminate (male) inflorescence at the tip of a stem or branch.
taxon (plural, taxa): a named group of organisms.
teosinte: wild grasses in the genus Zea that are closely related to maize (Zea mays).
tetraploid: having four sets of chromosomes per cell.
threshing: techniques like beating, flailing, or trampling that remove the straw and sometimes the chaff from a grain.
tiller: shoot of a grass plant that sprouts from near the base of the main stem or culm.
trade designation: a name given to a cultivated plant for marketing purposes.
trademark: a legally registered name, phrase, logo, etc., the use of which is restricted.
trade name: see trade designation.
transgenic organism: an organism containing genetic material from another organism transferred by genetic engineering.
transposition: a phenomenon in which genes or small pieces of DNA move to different locations in the genome. Transposition may cause mutations.
transposon: a gene or segment of DNA that moves to a different location in the genome. See also mobile genetic element.
trash: in sugarcane cultivation, dry plant material, like leaves, that are sometimes burned to make harvest easier.
triploid: having three sets of chromosomes per cell.
triticale: a wheat-rye hybrid in the nothogenus xTriticosecale.
tube cell: the cell in the pollen grain that grows to form the pollen tube. In flowering plants, the pollen tube is the structure that delivers the sperm to the embryo sac.
unisexual: in flowers, a flower that produces pollen or ovules, but not both.
utricle: in adlay (Coix lacryma-jobi), a hard, bead-like case surrounding the fruit.
variety: a taxon below the rank of subspecies and above the rank of form.
vascular bundle: a strand of vascular tissue.
vegetative: non-reproductive parts of a plant, like roots, stems, and leaves.
vegetative reproduction: in plants, reproduction without meiosis and fertilization. See also asexual reproduction.
vein: a strand of vascular tissue in a leaf.
vinasse: liquid waste left over during production of ethanol from sugarcane.
vitreous endosperm: dense endosperm with a glass-like appearance.
waxy corn: a type of maize whose kernels contain starch made up almost entirely of amylopectin, giving them a sticky quality.
wet milling: process for separating the parts of maize kernels (germ, fiber, protein, and starch) in which they are soaked in liquid, then ground, spun, filtered, and washed in a slurry.
wheat: species of domesticated cereals and their wild relatives in the genus Triticum.
white sugar: see refined sugar.
whole grain: grain used without the removal of the bran and germ.
wild rice: species of domesticated rice and their wild relatives in the genus Zizania.
winnowing: separating grain from loose chaff, traditionally by tossing the grain into the air and letting the chaff blow away.
xylem: water-conducting tissue in vascular plants.
xylem vessels: one of the types of water-conducting cells in flowering plants.
yeast: a type of single-celled fungus that can convert sugar into ethanol and carbon dioxide.
yellow dent corn: variety of corn that has yellow kernels that are dented at their ends.
zygote: the cell formed by fusion of gametes (an egg and a sperm).
Additional resources from the Paleontological Research Institution
Digital Encyclopedia of Ancient Life: Greek & Latin in Botanical Terminology: https://www.digitalatlasofancientlife.org/learn/embryophytes/botanical-terminology/
Glossary of botanical terms used in Poaceae (Flora of China online): http://flora.huh.harvard.edu/floradata/002/vol22/poaceaeglossary.htm
Talking glossary of genomic and genetic terms (National Human Genome Research Institute, NIH): https://www.genome.gov/genetics-glossary
Books, articles, and reports
Evert R. F., and S. E. Eichhorn. 2013. Raven Biology of Plants, 8th ed. W.H. Freeman and Co., New York, New York.
Simpson, B. B., and M. C. Ogorzaly. 2001. Economic botany, plants in our world, 3rd ed. McGraw Hill Higher Education, New York, New York.