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10.4.2. Angiosperms

Angiosperms

Angiosperms are the most highly evolved spermatophytes. They have adapted to all environments and climates on Earth, making them the most abundant and diverse group of plants.

The main characteristics of angiosperms are:

  • They have their seeds protected by fruits. This evolutionary advantage favors the dispersal of plants.
  • They have highly developed conducting vessels.
  • Its leaves are usually wide.
  • Like all cormophytes, they have rootsstems, and leaves.
  • They have showy flowers. They usually have a complete flower, with calyx, corolla, as well as stamens and/or carpels. The carpel is the female part of the flower and has an ovary that contains the ovules.
  • After fertilization, the flower loses the calyx and corolla, and the ovary, with the fertilized ovule, becomes a fruit, which can be:
    • Fleshy, soft, with the seed surrounded by a juicy mass, as in the case of peaches or pears.
    • Dry, hard, with the seed surrounded by a protective cover, as in the case of walnuts or almonds.
  • Most flowers are bisexual, but some are unisexual and have only the reproductive structures of the corresponding sex.
  • Its size is very varied, being able to be:
    • Herbs: like daisy or edelweiss.
    • Shrubs: such as roses or boxwood.
    • Trees: such as pear or peach.

Angiosperms are classified according to the number of leaves or cotyledons they produce when the seed germinates:

Dicots

The main characteristics of dicotyledons are:

  • The leaves usually have varied veining.
  • Flowers with calyx and corolla of different colours, formed by 4 or 5 sepals and petals or a multiple of 4 or 5.
  • They are usually trees (such as oaks and holm oaks, beech, olive, apple trees), shrubs (such as rosebushes), and can also be herbaceous (legumes, poppies, etc.).
  • The conductive vessels are arranged in the form of concentric rings in the stem.
  • The root usually has a central axis with ramifications.
  • The stem usually has branches.
  • The leaves usually have petioles and their veins branch.

Monocots

  • Monocot flowers usually have the same color calyx and corolla, and the number of sepals and petals is three or multiples of three.
  • The leaves usually have parallel nerves.
  • The conducting vessels are randomly arranged along the stem.
  • The roots are fasciculated.
  • The stem has no branches.
  • The leaves do not usually have a petiole and are wrapping around the stem.
  • Most monocots are herbaceous plants, such as cereals (wheat, barley, corn, etc.), bulbous plants (orchids, tulips, daffodils, etc.), and other larger ones, such as palm trees.