indehiscent one-seeded fruit in which the
seed is readily separated from the fruit wall. In
Carex, located inside a
perigynium. The term "
achene" is sometimes restricted to fruits developed from a superior
ovary, as in buckwheat (
Fagopyrum and other members of the
achene-like fruits developed from
inferior ovaries being called cypselas. See also
In biology, structures having the same function but different evolutionary origins. The fins of fish and whales are analogous, not
homologous. The pseudopetioles found in some
analogous, not homogolous, with the petioles of ordinary leaves.
Plants that produce flowers. The flowers of some plants have conspicuous colorful petals. In the
Cyperaceae (and several other flowering plant families), the flowers are inconspicuous. Angiosperms produce seeds that are enclosed in an
The family of
plants that includes sunflowers, daisies, dahlias, and dandelions. Its members have several small flowers or florets that have an
inferiorovary and are sessile on a common
A bristlelike stucture formed by one or more veins that extend beyond the edge or from the back or base of a structure, usually a structure that is part of the dispersal unit. In
grasses, awns are frequently associated with lemmas and, less frequently, with
glumes and paleas.
A type of wetland that is fed by precipitation; typically is acidic and nutrient poor; supporting plants adapted to low nitrogen environments. Because of the nutrient poor environment,
carnivorous plants are frequently present.
A hard, solid portion of tissue. Calluses often develop on diaspores. Because calluses are dense, diaspores tend to land
callus-first. This usually results in the
seed landing with its embryonic root pointing downwards. This gives the seedling a slight advantage in becoming established over those that land with their embryonic roots pointing upwards. In
callus is often developed at the base of a
lemma or spikelet. They are frequently sharply pointed.
Perennial species that form dense clumps of stems or culms. The term refers to the appearance of the plant above ground level. Cespitose plants may have rhizomes, but the rhizomes are short and do not connect the clumps. See also
Caespitose is an alternative spelling of
The family of
plants that have inflorescences composed of several small flowers that are sessile on a common
receptacle. The family has two scientific names,
Compositae. Examples of composites are dandelions, sunflowers, and daisies.
One of the whorls of
bracts that surround the stamens in most flowers. It is usually colorful. Corolla refers to all the petals in a
flower. Some flowers, such as those of buttercups and roses, have a
corolla composed of several separate petals. In other other flowers, such as those of tomatoes and lilacs, the
corolla is composed of
connate petals. Some
flowering plants, including members of the grass and sedge families (
Cyperaceae, respectively), do not have petals.
Stems that bear one or more inflorescences and have leaves with a
basalsheath. Used mostly (in North America) in discussions of the grass and sedge families (
Cyperaceae, respectively). See
monocot plant family comprised of approximately 100 genera and 5000 species worldwide (Goetghebeur 1998). Culm usually trigonous in cross section with three-ranked leaves with closed sheaths; with inconspicuous flowers that are subtended by a
generally known as a scale; perianth if present, is composed of bristles or a scale that wholly or partly surrounds the
The dispersal unit of a plant. This is often the fruit, but may be the fruit with various accessory structures. In
grasses, the dispersal unit is often a
floret or spikelet rather than just the
Carex, it is the
perigynium with the
To break up or fall off naturally. In
Carex, perygnia diarticulate from the floral axis at maturity. In
disarticulation may occur in below an
inflorescence, below a pair of spikelets, below individual spikelets, or below the florets.
Removed from a given area, generally used when the removal is the result of human action, either direct or indirect; used to describe populations of species known to have been present in an area within historical times.
Wetlands with a continuous source of groundwater that has relatively high concentrations of magnesium and calcium; because of the magnesium and calcium salts,
fens are alkaline to neutral. Compare with
The lower, often threadlike, part of a stamen. Anthers are attached to the
distal end of filaments. Together, a filament and
anther form a stamen. Wind-pollinated plants have stamens with long, flexible filaments and
versatile anthers. Animal-pollinated plants usually have short, stiff flaments.
A geographic area, usually rather large, that contains a more or less uniform assemblage of plants; the boundaries between floristic provinces are not precise; see map within key for Takhtajan's floristic provinces of North America.
flower consists of a calyx,
corolla, stamens and pistils and is the sexual reproductive structure. The
corolla is often colorful and showy. Many species have flowers that lack a
corolla, or stamens, or pistils, or some combination of these structures. In
perigynium is probably
homologous with a calyx; in
grasses, the lodicules are generally considered to be
homologous with the calyx.
Plants in which the seeds are produced inside an
ovary and fertilization involves two sperm nuclei, one to fertilize the egg, the second to fertilize the polar nuclei. In most
flowering plants, the
ovary is surrounded by stamens, petals, and sepals.
The lowest pair of
bracts in a typical grass spikelet. They are often described as empty because they do not have any structures in their axils. In some species, one or both
glumes may be absent or highly reduced. See also pseudospikelets
A family of herbaceous
flowering plants in which the leaves are two-ranked, the flowering stems (culms) are round in cross section, and the flowers are inconspicuous, being concealed between two
palea, and the fruit is a
Grasses constitute the fourth largest plant family in terms of number of species.
A cluster of flowers within a plant that may contain one to many flowers. There may be several inflorescences on a single plant. In the grass and sedge families (
Cyperaceae, respectively) the apparent inflorescences are, strictly speaking, synflorescences. The primary
inflorescence in the grass family is the spikelet; in the sedge family it is the spike. In most references however, the term
inflorescence is used for the synflorescence.
One of two
bracts that enclose the reproductive structures (lodicules, stamens, and pistil) of
grasses, the other being the
lemma is the lower, and usually the larger, of the two
bracts. It usually has an odd number of veins. Lemmas may also be sterile and lack a
In the grass and sedge families (
Cyperaceae, respectively), tissue or hairs at the junction of the
sheath and the
blade. Almost all members of both families have a
ligule on the
adaxial or inner side of the leaf; some bamboos also have ligules on the
abaxial side of the leaf. In sedges, the
ligule is usually hyaline to membranous.
Very small structures in
grasses that are located outside the stamens. The lodicules are
homologous with the calyx and/or
corolla of ordinary flowers.
Grasses have two, three, or no lodicules. They are not used in identification but are significant in classification. At
anthesis, they swell and help to spread open the
Plants whose seeds and seedlings have only one seedling leaf. Monocots also usually have a
corolla and calyx that consists of 3 parts or a multiple of 3, scattered vascular bundles in their stems, and often have leaves with parallel venation.
Poaceae) and members of the sedge family (
Cyperaceae) are monocots, as are lilies and orchids.
Plants that cannot grow in an area unless a particular condition is met;
obligate wetland species cannot grow in dry habitats;
obligate xeric species cannot grow in wetland habitats. Many species of Carex are
obligate wetland species, they can only grow in wetlands. See
One of two
bracts that enclose the reproductive parts of a grass, the other being the
palea is the upper of the two
bracts and usually has two major veins. Additional veins may be present also.
One of the
bracts that surrounds the stamens in an ordinary
flower. Petals are often colorful in visible light and often prominently marked in other invisible wavelengths; chiefly for the many pollinating insects that can see in ultaviolet light.
A term used for branches of the
Andropogoneae in which the spikelets are in sessile-pedicellate pairs, with
disarticulation being in the
rame, beneath the sessile spikelet. The pedicellate spikelet may be absent, vestigial, sterile, or
basal part of a leaf that wraps around the
grasses and sedges. In grass leaves, the
sheath is usually open - its margins may overlap but are not fused together. In
Carex, the sheaths are closed - the margins are fused together for most of their length.