Botany: Floral Structures and Anatomy

• The following are corrections to true or false statements about botany

Floral Symmetry and Structure

• Radial or actinomorphic symmetry occurs in flowers that can be divided into similar halves by multiple axes through the center.
• Gamopetalous flowers have fused petals and sepals that form a tube or bell-shaped corolla.

Phyllotaxy

• Whorled floral phyllotaxy involves more than two appendages per node in the receptacle: phyllotaxy is the arrangement of leaves on an axis or stem

Interwhorl Arrangement

• Alternate interwhorl arrangement exhibits sepals and petals that are opposite each other

Ovary Position

• Epigynous flowers have outer organs inserted above an inferior ovary.

Flower Anatomy

• Perigynous flowers have outer organs inserted into a hypanthium associated with a superior or inferior ovary.

Placentation

• Axile placentation features carpels folded inward forming septa, with ovules along the ovary's central axis (e.g., tomato).
• Parietal placentation features ovules attached to an elongated placenta on one side of the ovary, or marginal placentation (e.g., legume).
• Basal placentation features an ovule attached to the base of the ovary (e.g., sunflower).

Ovule Alignment

• An orthotropous ovule is aligned straight with the chalaza, funiculus, and micropyle in a straight line.
• Anatropous ovules become completely inverted during development, positioning the micropyle near the funiculus.

Inflorescence Types

• The raceme inflorescence has pedicellate, not sessile, florets attached to the inflorescence axis.
• A corymb is a flat-topped raceme with pedicels of different lengths.
• A cyme inflorescence has three or more florets coming from a common point, where the central floret blooms first.
• The head inflorescence features sessile florets attached to a broad flat peduncle.

Seed Development and Germination

• Dicot seed development stages: globular, heart, torpedo, and mature stages.
• The epicotyl of a plant embryo develops into the seedling stem and leaves, while the radicle develops into the seedling root.
• The embryo cotyledon serves as an endosperm storage structure in monocots, and absorbs endosperm in dicots.
• Dicot seeds exhibit epigeal germination, where most seed parts are carried above ground.