Primitive and advanced characteristics of Angiosperms with special reference to Magnoliaceae , Ranunculaceae , Orchidaceae and Asteraceae.
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All angiosperms have flowers at some stage in their life. ...
Angiosperms have small pollen grains that spread genetic information from flower to flower. ...
All angiosperms have stamens. ...
Angiosperms have much smaller female reproductive parts than non-flowering plants, allowing them to produce seeds more quickly.
The earliest known flowering plants date back to about 130 million years ago. According to Cronquist (Evolution and Classification of Flowering Plants, 1988), the most primitive of all living angiosperms belong to the subclass Magnoliidae. This subclass contains several primitive plant families, including the water-lily family (Nymphaeaceae), buttercup family (Ranunculaceae) and magnolia family (Magnoliaceae). The magnolia family has the following primitive characteristics: (1) Large flowers with numerous petals and sepals (called tepals because they are similar in size and shape); (2) Numerous spirally arranged stamens at the base of a conelike receptacle bearing numerous spirally arranged carpels. At maturity the carpels develop into a woody, conelike aggregate of seed-bearing follicles. Each seed has a fleshy red outer layer (aril) and hangs from its follicle by a threadlike stalk. Other primitive floral characteristics are radial symmetry or actinomorphic (floral parts similar in size & shape), perfect (with functional androecium and gynoecium), complete (with all 4 floral parts: calyx, corolla, androecium & gynoecium), and floral axis (receptacle) elongated. The latter characteristic is clearly visible in the magnolia blossom. With all the woody, spirally arranged carpels (follicles), this axis truly resembles a conelike structure.
Herbs, leaves exstipulate, incised blades, sheathing bases, flowers hypogynous, spiral or spirocyclic; sepals often decidous, usually petaloid; calyx and corolla free; stamens indefinite, free; carpels polycarpellary, apocarpous; fruit aggregate.
The Orchidaceae are a diverse and widespread family of flowering plants, with blooms that are often colourful and fragrant, commonly known as the orchid family.