Angiosperms and Reproductive Development

Vocabulary practice flashcards covering angiosperm evolution, life cycles, flower morphology, and reproductive mechanisms.

Angiosperms (Phylum Anthophyta)

Highly specialized flowering plants that emerged about 100-200 million years ago and represent approximately 80% of all known plant species (about 270,000 species).

Archaefructus

The oldest known angiosperm, which is now extinct.

Amborella

The most basal, living angiosperm.

Eudicots

A major class of angiosperms comprising about 175,000 species (e.g., trees, shrubs, snapdragons, and peas) that are pollinated by wind and animals.

Monocots

A major class of angiosperms comprising about 65,000 species (e.g., grasses, lilies, palms, irises, grains, and orchids) that are wind- or self-pollinated.

Ploidy

The number of complete sets of chromosomes present in a cell.

Mitosis

Cell division occurring in somatic cells where chromosomes are separated into two identical sets, producing two identical diploid ($2n$) cells.

Meiosis

Cell division occurring in sex cells where chromosomes are halved, producing four genetically distinct haploid ($1n$) cells.

Calyx

The collective term for all the sepals of a flower, which serve to protect reproductive organs.

Corolla

The collective term for all the petals of a flower, which serve to attract pollinators.

Androecium

The collective term for all the stamens (male reproductive organs) of a flower.

Gynoecium

The collective term for all the carpels (female reproductive organs) of a flower.

Complete Flower

A flower that contains all four floral whorls: sepals, petals, stamens, and carpels.

Incomplete Flower

A flower that lacks one or more of the four floral whorls.

Monoecious Plant

A plant species that has separate male and female flowers located on the same individual plant (e.g., black walnut).

Dioecious Plant

A plant species that has separate male and female flowers located on separate individual plants (e.g., boxelder maple).

Stamen

The male reproductive structure of a flower, consisting of a pollen-producing anther and a supporting filament.

Carpel

The female reproductive structure of a flower, consisting of a stigma, style, and ovary.

Simple Pistil

A pistil consisting of a single carpel or multiple unfused carpels.

Compound Pistil

A pistil consisting of several fused carpels.

Receptacle

The modified stem structure that bears the floral whorls.

Pedicel

The stalk that supports an individual flower.

Perfect Flower

A flower that possesses both functional stamens and pistils.

Imperfect Flower

A flower that lacks either functional stamens or pistils.

Embryo Sac

The female gametophyte (megagametophyte) of an angiosperm, housed in the ovule, containing 8 polar nuclei.

Generative Cell

A haploid cell inside a pollen grain that divides by mitosis to produce two sperm cells.

Tube Cell

A cell inside a pollen grain that grows to form the pollen tube through which sperm travel to the embryo sac.

Double Fertilization

A process unique to angiosperms where one sperm fertilizes the egg cell to produce a diploid ($2n$) zygote, and a second sperm combines with two polar nuclei to form a triploid ($3n$) endosperm.

Endosperm

A triploid ($3n$) tissue resulting from double fertilization that provides nutrition to the developing embryo.

Hypogynous Flower

A flower featuring a superior ovary situated above the point of attachment of other floral parts.

Epigynous Flower

A flower featuring an inferior ovary situated below the point of attachment of other floral parts.