There are almost 300 000 species of angiosperms in the world of plants. The majority of them are dicotyledons. Most of them are annual plants and perennials, although trees and bushes are also present. Almost all of the species of deciduous trees are dicotyledons. Their leaves have irregular and reticular venation (cotyledons have parallel venation). Another qualities are:
– Vascular bundles organized into a circle are “open”, which means that they allow the plants to the secondary growth (xylem is in the center of the stem, while phloem is pushed outward by the new cells)
– They are based on 4 or 5 whorls with calyx and corolla.
– Dicotyledons families: ranunculaceae [crowfoot family], rosaceae [rose family], fabaceae [bean family], brassicaceae [cabbage family], compositae [sunflower family], nymphaeaceae [water lilies].
The most famous dicotyledons:
– The crowfoot family consists of approximately 1500 species of herbaceous plants and bushes. Many of them grow in gardens and meadows (marigolds, liverleaves, anemones, clematises, adonises).
– Nymphaeaceae (water lilies) – tropical species, plants growing in the temperate zone. They can be seen in nature as well in in botanical gardens.
– Primulaceae – 1000 species. The most famous: primulas, cyclamens, lysimachia.
– Brassicaceae (cabbage family) – 3200 species. The most famous: cabbage.
– Solanceae (nightshades) – 2000 species. The most famous: potato.
– Compositae (sunflower family) – approximate 20 000 species. Their flowers have irregular structure.
Plants used by mankind.
– The most basic influence for humanity imposes Poaceae family (for example rice, wheat, rye, sugar cane) which belongs to cotyledons.
However, dicotyledons are also important (potato, carrot, cabbage, beetroot, onion, asparagus, legume and many more vegetables, bushes and fruit trees).
– Some of the dicotyledons are being turned into animal feed. They are also a source of variety of substances used in medicine.
– Among fabales there are such plants as beans, peas, soya, clover, acacia (its juice is used in producing acacia gum), true indigo (pigment production) and peanuts.
– Apiaceae (parsley family) – the ones characterized by a strong, intensive scent and taste are being exploited (coriander, parsley, cumin, celery).
– Many cultivars have been made from a cabbage, such as: brussels sprout, savoy cabbage, collards, turnip, cauliflower, kale, broccoli, rape.
– Potato (Solanceae family) – In many countries in the world this plant is considered to be a basic element of food. People have started to grow it in South America approximately 2000 years ago. It was brought to Europe by Columbus. Its leaves (as well as other plants of this family) are poisonous.
– Compositae (sunflower family) – thyme and majorjam.
– To ensure their safety from herbivore animals, many plants produce poisonous substances. Those toxins are being used in manufacturing medicines (and other remedies) used in everyday life.
– Sunflower family, medical herbs: mint, melissa.
– Essential oils used in cosmetics industry are made from rhizome of iris.
– Sunflower family – sunflowers, common dandelions, daisies, asters, marigold, chrysanthemums, gerberas, lavender, thymes and rosemary.
– The most popular cactuses, which are resistant to long-lasting droughts (they also protect our eyes from radiation), come from South America – opuntias.
– Irises, peonies, lilies-of-the-valley (protected by law), lupine.