A B C D E F G H I J L M N O P R S T U V W X

P

In grasses, the upper bract which, with the lemma (lower bract), encloses a flower's/floret's reproductive organs. Each grass species has specific characteristics for the palea that can help with identification.

Having three or more lobes or veins arising from a common point (such as with a leaf)

A leaf which is divided into smaller leaflets, those leaflets originating from a single point of attachment, similar to the fingers on a hand

A leaf blade having the principal veins radiate out from a single point, most commonly where the leafstalk/petiole ends, and diverge out toward the edge of the leaf

A branched, racemose inflorescence - that is, an inflorescence with pedicellate lateral flowers, or spikelets (grasses) - in which the lateral branches are also branched.

A non-mutual relationship in which one organism depends on another for its nutrients, or other services, and benefits at the expense of the other (its host)

A flower stalk of a single flower, or grass spikelet, within an inflorescence; the stem supporting the entire inflorescence is called a peduncle

A primary flower stalk, supporting a solitary flower or an entire cluster of flowers (inflorescence)

A fleshy, several-seeded fruit that has developed from one flower having a single ovary divided into several carpels, which develops a firm or tough rind as it matures (such as a melon, squash, cucumber).

A plant or plant species whose life cycle lasts for three or more years

Describes a flower having both pistil and stamens - female and male reproductive organs; bisexual

Collectively, the calyx (all sepals) and corolla (all petals), or if similar in appearance the tepals, of a flower

The wall of a fruit.

a flower's ovary position with the sepal, petal, and stamen whorls attached to a surrounding cup

A modified leaf in the whorl of flower parts that surround the whorls of the reproductive parts (stamens and the pistil). Typically they are colored and showy so as to attract and guide their pollinators. Collectively, all of the petals are called the corolla.

The stalk of a leaf, that attaches a leaf blade to the plant stem

A precisely defined point in the life cycle of a plant or animal, generally marking the start or end point of a phenophase. The occurrence of a phenological event can be pinpointed to a single date and time (in theory, if not in practice). Examples include the opening of the first flower on a plant, the end of leaf fall on a tree, the first appearance of a particular songbird species in spring, or the start of fish migration up-river to spawn. (Note: The definition of the term “phenological event” has not yet been standardized and varies among scientists. The definition presented here reflects our usage of the term on the USA-NPN website.)

A vegetative or reproductive phase in a plant's life cycle, such as the opening of leaf buds or the release of pollen from flowers

The state of one or more phenophases for an individual or species at a given moment. Phenological status could include but is not limited to measures of the state of flowers, leaves, and fruits for plants or migration, breeding, and development for animals. For example, the phenological status of a plant might be: has flowers and unfolded leaves; does not have ripe fruits. For birds, an example might be: is present, is an adult, and is calling; is not building or sitting on a nest.

Phenology refers to recurring plant and animal life cycle stages. It is also the study of these recurring plant and animal life cycle stages, especially their timing and relationships with weather and climate.

An observable stage or phase in the annual life cycle of a plant or animal that can be defined by a start and end point. Phenophases generally have a duration of a few days or weeks. Examples include the period over which newly emerging leaves are visible, or the period over which open flowers are present on a plant. (See also phenological event) (Note: The definition of the term “phenophase” has not yet been standardized and varies among scientists. The definition presented here reflects our usage of the term on the USA-NPN website.)

The food/sugar conducting tissue in vascular plants, distributing the photosynthetic products within the plant

The manufacturing of food/sugar in plants, some algae and cyanobacteria - by converting light energy to chemical energy and storing it in the bonds of sugar. Carbohydrates are synthesized from carbon dioxide and water, with oxygen released as a by-product.

An individual bract under a flower head of a plant, within the involucre, such as occurs especially in, but not exclusively, the Asteraceae plant family - in daisies, dandelions, sunflowers, thistles, asters, etc. 

Having two rows of branches, lobes, leaflets, or veins arranged on either side of a common axis. The word "pinnate" means "like a feather", which might help you to visualize its structure/architecture.

A leaf which is divided into smaller leaflets, those leaflets arranged on each side of the leaf's central stalk/rachis (axis). A pinnate leaf can either be even-pinnate or odd-pinnate, indicating whether or not a terminal leaflet exists: even-pinnate leaves have pairs of leaflets attached along the leaf's central stalk/rachis (axis) with no terminal leaflet, although may occasionally have a tendril (therefore an even number of leaflets in total); odd-pinnate leaves have a terminal leaflet at the end of the leaf's central stalk/rachis (axis) along with pair(s) of leaflets attached along the leaf's rachis (therefore and odd number of leaflets in total). A bipinnately compound leaf is twice pinnate; a leaf blade divided into leaflets and having twice-diverged branching.

A leaf blade having conspicuous lateral veins which diverge from the midvein towards the leaf margin and are approximately parallel to one another

The female reproductive part of a flower made up of the ovary, style (stalk) and stigma (sticky tip that receives pollen).

A female flower, with or without a perianth, that has only functioning female reproductive parts, or if male reproductive parts (stamens) are present, they are non-functioning

The spongy, central tissue in some twigs, stems, and roots

A small plant, usually one produced vegetatively (asexually), from a parent plant 

A specialized, erect root (aerial) in certain aquatic plants that protrudes above the soil or water surface and has many lenticels, which supports gas (oxygen, etc.) exchange

A mass of microspores in a seed plant, usually appearing as a fine dust. Pollen grains are transported (typically by wind, water, insects or animals) from a stamen to a pistil, where fertilization occurs.

The conical, pollen-bearing unit of a conifer (male strobilus)

The slender tube that grows from pollen grain and holds the sperm, penetrates and delivers the sperm to the ovule

The release and transfer of pollen from the anther of the flower to a stigma of a flower, sometimes within one plant (self-pollination) or from one plant's anthers to the stigma of a different plant (cross-pollination)

Having more than two forms or distinct morphological variants, such as when a plant species has three forms of leaves - as with Sassafras

A fleshy or pulpy, several-seeded fruit that has developed from one flower having a single ovary divided into several carpels surrounded by a hypanthium/receptacle from flower parts which then becomes fleshy/pulpy as it matures (such as an apple). (see ovary position - perigynous - for further information)

The portion of the plant embryo in a seed below the cotyledons that will develop into the primary root

An adventitious root that arises from a stem that provides support for a plant (aerial)

An adventitious root that arises from a node, such as the node of a stolon/runner that will anchor new growth and initiate new plants

Any unit or structure having the capacity to generate a new plant, whether through sexual (such as with seeds) or asexual (vegetative) reproduction. This includes seeds, spores, and any part of the vegetative body capable of independent growth if detached from the parent plant

An often-modified, basal pair of leaflets of a compound leaf appearing very close to the plant stem, close to where stipules might occur