Angiosperms (The Flowering Plants)

A comprehensive set of vocabulary flashcards covering the definition, history, classification, life cycle, and morphology of angiosperms based on the lecture transcript.

Angiosperm

A synonym for flowering plant, meaning "seed within a vessel" or "enclosed seed."

Ovary

A structure in angiosperms that encloses the ovules and eventually forms a fruit.

Integument

An extra layer or two of sporophyte tissue that protects the embryo and creates the ovule.

Carpel

A modified leaf that encapsulates seeds and develops into the fruit, which is a unique angiosperm feature.

Abominable mystery

A term used by Charles Darwin to describe the origin of flowering plants because they appear suddenly in the geologic record without a clear fossil history.

Archaefructus

Small, herbaceous macrofossils found in China that flourished in aquatic habitats between $125$ and $140$ million years ago.

Artificial System of Classification

A classification system based on superficial characters such as plant habit (herb, shrub, or trees).

Natural System of Classification

A system where organisms are classified based on natural affinities and basic similarities in morphology rather than a single character.

Phylogenetic System of Classification

Classification based on evolutionary features.

Monocotyledons (Monocots)

Plants typically characterized by a single cotyledon, parallel-veined leaves, flower parts in threes, and an absence of secondary growth.

Dicotyledons (Dicots)

Plants typically characterized by embryos with two cotyledons, net-veined leaves, flower parts in fours or fives, and vascular bundles arranged in a ring.

Pedicel

A stalk that ends in a primordium which develops into a flower bud.

Receptacle

The expanded tip of the pedicel to which the remaining flower parts are attached.

Androecium

The third whorl of a flower consisting of stamens where pollen is produced.

Anther

The pollen-bearing part of a stamen.

Gynoecium

The fourth whorl at the center of the flower where the female gametophytes are housed; it consists of one or more carpels.

Stigma

The sticky or feathery tip of the carpel that helps pollen grains adhere.

Style

The neck or stalk connecting the stigma and the ovary.

Nectaries

Glands that secrete nectar, a fluid contains sugars and amino acids used to attract pollinators.

Double Fertilization

A unique angiosperm event where one sperm unites with the egg to form a zygote and the other sperm unites with two polar nuclei to form a triploid primary endosperm nucleus.

Polar nuclei

Two nuclei that migrate toward the center of the megaspore to create the central cell.

Synergids

Two cells located next to the egg in the female gametophyte group closest to the micropyle.

Antipodals

Three cells at the end of the embryo sac that have no apparent function and eventually break down.

Embryo sac

The large sac containing eight nuclei in seven cells that constitutes the female gametophyte.

Micropyle

A small gap or pore at one end of the ovule formed by the integuments.

Generative cell

A cell within the pollen grain that divides to produce two sperm cells.

Endosperm

Triploid tissue formed after fertilization that nourishes the embryo in angiosperms.

Seed coat

A relatively impermeable outer layer of a seed developed from the integuments of the ovule.

Dormancy

A state maintained by seeds under unfavorable conditions to postpone development until better conditions arise.