Morphology of Flowering Plants

Mangrove plants

Pneumatophores are negatively geotropic respiratory roots found in mangrove plants such as Avicennia, Ceriops, and Sonneratia. They grow upward in waterlogged, anaerobic (oxygen-poor) soil to absorb oxygen for respiration.

Stem tuber

Potato (Solanum tuberosum) is a stem tuber — a swollen tip of an underground lateral branch of the stem. Evidence: it has nodes ('eyes') bearing axillary buds and scale leaf scars, which are characteristics of stems, not roots.

Onion

Onion (Allium cepa) is a bulb — a much reduced disc-shaped stem (basal plate) bearing tightly packed fleshy scale leaves that store food. Ginger is a rhizome; Colocasia is a corm; Potato is a tuber.

Parallel venation

Monocot leaves have parallel venation — the veins run parallel to each other without forming a network. Examples: Grass, Banana, Maize, Sugarcane, Wheat. Reticulate venation (veins form a net-like network) is characteristic of dicots.