The new corms store food produced by the growing plant and then go through the next dormant period to produce their own plants and corms the following season. Bulbs are different from corms, although the latter are often called bulbs. The portion of the plant that everyone recognizes as the stem is more precisely called the aerial stem . Its main function is to bear leaves, the stem with its leaves being called the shoot. In addition to bearing leaves, the aerial stem performs the vital functions of transporting water and minerals up from the roots to the leaves and transporting manufactured food substances as they are distributed to all parts of the plant for use or storage.
Radical leaves grow directly from a non-aerial stem.
See the accompanying illustration and the definitions in the glossary of botanical terms for explanations of the various shapes and forms of leaves. The primary function of the average green leaf is to carry on photosynthesis - the process by which plants use the energy of sunlight to combine simple substances absorbed from the soil and the air into complex food substances. In the process, plants use up carbon dioxide from the air and produce oxygen. Green leaves contain various other pigments as well, but these show up only when the leaf dies and its chlorophyll breaks down. The yellow and red autumn colors of many trees are due to leaf pigments which are present but are masked by the chlorophyll while the leaves are alive.