Life

Angiosperms

Angiosperms include approximately 220,000 species (over one half of the known higher plants) and their classification is very complex and detailed and not perfectly defined yet. Angiosperms can be divided into two large groups: dicotyledons and monocotyledons. The features that distinguish Dicotyledons from Monocotyledons are generally quite clear and peculiar. The most important discriminating parameter is the number of cotyledons contained in the embryo: Dicotyledons own two cotyledons only (rarely 1, 3 or 4), while Monocotyledons own only one (or sometimes none at all). Other features shared by Angiosperms are the presence of a trunk, leaves and roots and the production of flowers, fruits and seeds. They may be have either a herbaceous or wooden "habitus". Herbaceous plants can be annual, biennial and perennial. In annual plants, the vegetative and reproductive cycle is completed in one year, while biennial plants stock up food in the first year, then bloom and make fruits in the second year, then the plant dies. Perennial herbaceous plants bloom every year. Wooden plants are all perennial, and can be divided into shrub or tree plants. The former have a limited height and their branches depart from the basal portion of the plant; trees can reach remarkable heights and have a branched trunk. In fact, the distinction between trees and shrubs is not always easy, since many plants can look differently according to where they live.