SYSTEMATICS OF WOODY PLANTS - ANGIOSPERMS

Characteristics of angiosperms

Angiosperms (Angiospermae - Angiospermophytina) it is the most developmentally advanced group among vascular plants. In the woody part of the vascular bundle, wide vessels are developed – trachea and in the bast part sitcos. The origin of angiosperms in the Cretaceous 200 million years ago is probably related to a change in climatic conditions:

• warming
• decrease in air humidity
• there was a need to protect the egg from drying out.

Morphology of angiosperms

A flower of a new quality was created – a complete flower, adapted to insect pollination. It includes:

• flower bed
• flower wrappers
• genitals

The female (♀) sexual organs (spore leaves) of angiosperms are called "carpels", from which a pistil is formed when they fuse together. Its lower part is the testicle, which encloses the egg. The fertilized egg turns into a seed enclosed in the fetus, the fetus being formed by the transformation of the walls of the testicle into a pericarp. The upper part is the scar. Pollen is trapped on the scars. Pollen grains are caught on the scars and both parts are connected by a stalk.

The male (♂) sexual organs (spore leaves – stamens) are divided into a wormwood (pollen is formed on it) and a thread.

Angiosperms are divided into two classes:

1. Dicotyledonopsis (Dicotyledonopsida), or magnolia (Magnoliopsida)

2. Monocotyledonopsida, or lilies (Liliopsida)

Dicotyledons:

• they are developmentally older, the embryo is with two cotyledons
• the root system is characterized by the main root, which branches into lateral ones
• they have a secondary thickening of the stem, which allows the formation and growth of wood
• in most cases, these are trees of the temperate and cold zone, but also of the tropics
• in terms of the abundance of species, there are about 4 times more of them than monocotyledons

Monocotyledons:

• the embryo is with one cotyledon
• the root system has a stunted main root, it is made up of adventitious roots
• flowers are trifoliate
• they are mostly plants of the tropics and subtropics (palm trees)
• there is no secondary thickening of the trunk (the trunk is of the same thickness along its entire length)

 Angiosperms in terms of pollination can be:

• self-pollinating – own pollen
• alien-pollinated – foreign pollen of the same species or a related species
• by pollinators:
  • Insect-pollinated
  • wind-pollinated
  • water-pollinated
  • zoo-pollinated