Plant Kingdom Chapter 5 PDF

Chapter 5: Plant Kingdom 3.2.2. Subphylum of Angiosperms The main feature of angiosperms is the typical flower containing the reproductive organs. Angiosperms are the most diverse group (about 240,000 species), and the most advanced of the Plant Kingdom. They include both herbaceou...

Chapter 5: Plant Kingdom 3.2.2. Subphylum of Angiosperms The main feature of angiosperms is the typical flower containing the reproductive organs. Angiosperms are the most diverse group (about 240,000 species), and the most advanced of the Plant Kingdom. They include both herbaceous and woody plants. In Angiosperms (angio: envelope and sperm: seed), the bi-integumented ovule are enclosed in a protective envelop, the carpel, more or less closed in an ovary. After fertilization, the ovary becomes a fruit and the ovule a seed. This group is characterized by a particular mode of fertilization: the double fertilization. Wood is mainly comprising heterogeneous real vessels and fibers. A complete flower consists of four floral whorls inserted on the receptacle. These whorls are from the outside to the inside: Sepals: Sepals mostly green , which together form the calyx Petals: usually colored, which together constitute the corolla. The calyx and the corolla are the sterile protective parts and do not have a reproductive role. Together they form the perianth.  Stamens: ♂ reproductive parts, which together form the androecium.  Carpels: ♀ reproductive parts, which together form the gynoecium or pistil. Each carpel is formed of a lower part, the ovary containing one or more ovule, an upper part, the stigma which receives pollen grain. The pollination (transport of the pollen from the male organ to the female organ) is insured by wind, animals or humans Angiosperms are divided into two classes: classes Liliopsida (Monocots, one cotyledon) and Magniliopsida (Dicots, two cotyledons). 3.2.2.1 Class of Monocotyledons  One cotyledon.  Herbaceous plants (except palms...).  Fibrous root system  Number of floral parts by three (or multiple).  Leaves with parallel veins.  Conductive tissues of stems are numerous and scattered.  3.2.2.2. Class of Dicotyledons  Two cotyledons.  Herbaceous or woody plants.  Taproot system usually present.  Number of floral parts four or five (or multiple).  Leaves with pinnate, palmate or reticulate veins.  The primary (primary growth) conductive tissues of the stem are arranged in a ring.  Secondary tissues (wood, liber) and cambium.