stipulari

Stipulari refers to stipules, the small leaf-like appendages located at the base of the leaf stalk (petiole) in many flowering plants. They can occur as paired structures at the base of a leaf or as interpetiolar stipules between adjacent leaves. The term is used in botany to describe the presence and form of these structures.

Stipules show considerable variation in size, shape, and texture. They may be foliaceous (leaf-like), scale-like, or reduced to tiny scales or spines. In some species the two stipules are free from the leaf blade, while in others they are fused with the leaf base or with each other to form a protective sheath around the stem or bud. Some stipules are caducous, falling early as the leaf expands; others persist through leaf maturation.

Development and function: Stipules develop from the base of the leaf primordium during leaf initiation. Their primary presumed function is to protect developing buds and leaf primordia. In some taxa stipules may contribute to shading or defense, and when large and leafy they can participate in photosynthesis, though in many species they are small and inconspicuous.

Taxonomic significance: The presence or absence of stipules, as well as their shape, size, and arrangement (such as interpetiolar versus paired at the leaf base), are used as diagnostic characters in plant identification and classification. Stipules are particularly variable in families such as Fabaceae, Rosaceae, and Rubiaceae, while in many monocots they are reduced or absent.

See also: Stipule.