Illustration of the structure of typical plant cells: cell wall, pectin, plasma membrane, cytoplasm, vacuole, vacuolar membrane (tonoplast), mitochondrion, nuclear membrane, chromatin, nucleolus, nucleoplasm, Golgi apparatus, endoplasmic reticulum, ribosomes, chloroplast, grana, and pyrenoids.

Illustration of the structure of typical plant cells with labels: cell wall, pectin, plasma membrane, cytoplasm, vacuole, vacuolar membrane (tonoplast), mitochondrion, nuclear membrane, chromatin, nucleolus, nucleoplasm, Golgi apparatus, endoplasmic reticulum, ribosomes, chloroplast, grana, and pyrenoids.

Conceptual illustration of a tree with a root system that mimics the bronchial tree structure of the lungs.

Illustration of nuts and nut kernels of the Persian walnut tree, Juglans regia. Walnut oil is pressed from the kernels of the nut. The tree is shown at right.

Illustration of the Aleppo pine (Pinus halepensis), a detailed view of the branches with the leaves and cones, with the tree shown above. A variety of rosin obtained from the Aleppo pine is known as "pece greca," or Greek pitch.

Cherry tree in autumn

Cherry tree in spring

Cherry tree in summer

Cherry tree in winter

Illustration of Eurasian milfoil (Myriophyllum spicatum), an aquatic plant.

Illustration of a food web with labels. A food web is a set of interconnected food chains by which energy and materials circulate within an ecosystem.

Northern milfoil.

Illustration of purple loosestrife (Lythrum salicaria).

Illustration of wild calla (Calla palustris), a flowering plant native to cool temperate regions of the Northern Hemisphere, growing in bogs and ponds.

Labelled illustration of the wild iris (Dietes iridioides).

Illustration of the wild iris (Dietes iridioides).

Illustration of the concept of photosynthesis: a molecular model of chlorophyll with green leaves.

Illustration of a plant cell, showing various organelles.