Biology of Flowering Plants

Study Notes

Flowers and fruits are the least affected by environmental changes, making them important for angiosperm classification.
The essential steps of sexual reproduction in flowers include: meiosis, pollination, fertilization, fruit and seed development, seed and fruit dissemination, and seed germination.

A typical flower consists of four whorls of modified leaves: sepals, petals, stamens, and carpels, all attached to the receptacle.
Sepals enclose the other flower parts in the bud and are generally green.
Petals are the conspicuous, colored, attractive flower parts, collectively known as the corolla.
Stamens form a whorl, lying inside the corolla, and consist of a slender stalk (filament) and an anther.
The whorl or grouping of stamens is called the androecium.
Carpels comprise the central whorl of modified floral leaves, known as the gynoecium.

A pistil may be composed of a single carpel or several united carpels in the center of the flower.
A pistil consists of three distinct parts: the ovary, style, and stigma.
The ovary contains ovules, the style supports the stigma, and pollen is deposited on the stigma.
The receptacle is the enlarged end of the flower stem or stalk to which the sepals, petals, stamens, and pistils are attached.

The term perianth refers to the calyx and corolla collectively.
A tepal refers to an individual part of the perianth, often used to describe flowers with morphologically indistinguishable calyx and corolla.
An involucre is a collection of bracts that subtend flowers or compact clusters of flowers.