Science

Vascular system

Collection of specialized tissues in some plants that transports mineral nutrients up from the roots and brings sugars down from the leaves.

Xylem

Vascular tissue that carries water upward from the roots to every part of a plant.

Phloem

The vascular tissue through which food moves in some plants.

Nonvascular plants

Plants that absorb water and other substances directly through their cells.

Gymnosperms

A plant that produces seeds that are exposed rather than seeds enclosed in fruits.

Angiosperms

A flowering plant which forms seeds inside a protective chamber called an ovary.

Spore

A tiny cell that is able to grow into a new organism.

Sporophyte

Diploid, or spore-producing, phase of an organism (2 sets of chromosomes).

Gametophyte

Haploid, or gamete-producing, phase of an organism (one set of chromosomes).

Gamete

A mature haploid male or female cell that is able to unite with another of the opposite sex in sexual reproduction to form a zygote.

Zygote

A diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.

Alternation of generations

Life cycle that has two alternating phases—a haploid (N) phase (gametophyte) and diploid (2N) phase (sporophyte).

Sori

Fern structures in which spores are produced (clusters of sporangia).

Frond

Leaf of a fern.

Sporangia

Multicellular organs that produce spores.

Rhizoid

A thin, rootlike structure that anchors a moss and absorbs water and nutrients for the plant.

Rhizome

A horizontal, underground stem that produces new leaves, shoots, and roots.

Evergreen

A tree that does not lose its leaves in the winter and stays green all year round.

Deciduous

Trees and shrubs that shed their leaves at the end of the growing season.

Conifer

A cone-bearing tree.

Cycads

Gymnosperms that grow in tropical or subtropical areas; look like palm trees with cones.

Ginkos

Single species of tree, Ginko biloba, with separate male and female trees.

Yews

A tree which has red berry-like fruits.

Mosses

Soft, small, green, nonvascular plants found on the ground near water.

Liverworts

A nonvascular plant shaped like a human liver, found growing as a thick crust on moist rocks or soil along the sides of a stream.

Ferns

Numerous flowerless, seedless vascular plants having roots, stems, and fronds, reproducing by spores.

Cotyledon

First leaf or first pair of leaves produced by the embryo of a seed plant.

Stomata

Small openings on the underside of a leaf through which oxygen and carbon dioxide can move.

Stamen

The male reproductive organ of a flower.

Anther

The part of a stamen that contains the pollen.

Pistil

The female part of the flower.

Ovary

A flower structure that encloses and protects ovules and seeds as they develop.

Style

The stalk of a flower's carpel, with the ovary at the base and the stigma at the top.

Stigma

The top of the female part of the flower which collects pollen grains.

Perfect

Having male and female reproductive organs in the same plant or animal.

Imperfect

Having male and female reproductive organs in separate plants or animals.

Polygamous

A plant that has both perfect flowers and imperfect flowers of both sexes.

Petal

A colorful, leaflike structure of some flowers.

Sepal

A leaflike structure that encloses the bud of a flower.

Root

An organ in vascular plants that anchors the plant and enables it to absorb water and minerals from the soil.

Stem

Supporting structure that connects roots and leaves and carries water and nutrients between them.

Flower

The reproductive part of the plant.

Fruit

A mature ovary of a flower that protects dormant seeds and aids in their dispersal.