Where do you find ligule ?

Explanation:

• A ligule is a small, scale-like structure present at the base of the leaf or its segments in certain plants. It is primarily found in members of the Lycopodiophyta group, such as Selaginella. The ligule is an important characteristic used to differentiate Selaginella from other plants in its group.
• The primary function of the ligule is believed to be related to protecting the growing leaf tissue and facilitating water absorption.
• The ligule is located at the base of the leaf, within a specialized structure called the leaf axil. It plays a role in protecting the developing leaf and may help with water retention and absorption.

Other Options:

• Azolla: Azolla is a genus of aquatic ferns commonly used as biofertilizers due to their symbiotic relationship with nitrogen-fixing cyanobacteria. Azolla does not have ligules; its leaves are simple and adapted for floating on water surfaces.
• Equisetum: Equisetum, commonly known as horsetail, is a genus of vascular plants known for its jointed stems and lack of true leaves. Instead, it has tiny scale-like leaves arranged in whorls. Ligules are absent in Equisetum.
• Marsilea: Marsilea is a genus of aquatic or semi-aquatic ferns with clover-shaped leaves. These plants do not have ligules; their leaves are morphologically distinct from those of Selaginella.