Thorns, spines, and prickles
Videos
In plant morphology, thorns, spines, and prickles, and in general spinose structures, are hard, rigid extensions or modifications of leaves, roots, stems, or buds with sharp, stiff ends, and generally
Prickles on a blackberry branch
(A) Thorn or spine (B) Prickle
Smooth, featureless Citrus thorn.
Gymnosporia buxifolia thorn, its leaves, nodes, and emergence from an axillary bud demonstrating its nature as a branch.
Leaf
Videos
A leaf is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage"
Leaf of Tilia tomentosa (silver linden tree)
Vein skeleton of a leaf. Veins contain lignin that make them harder to degrade for microorganisms.
Near the ground these Eucalyptus saplings have juvenile dorsiventral foliage from the previous year, but this season their newly sprouting foliage is isobilateral, like the mature foliage on the adult trees above.
Rosa canina: Petiole, two stipules, rachis, five leaflets