Botany and Plant Science

The cork is produced by the activity of phellogen.

Vessel and companion cells are the characteristics of angiosperm.

Roots prevent soil erosion.

In malvaceae, the androecium is monadelphos.

The embryo-sac of seed plants develops from the megaspore.

Zygomophic flowers occur in pea.

A linear tetrad of 4 cells lying in an axial row develops during the development of the embryo sac.

Rose plant reproduces through vegetative propagation, i.e. giving rise to a new plant of its own kind with the involvement of a part other than the flower. The stem of rose, when buried in soil, gives rise to a new rose plant.

The spore forming body in ferns is known as sori. These spores are means of reproduction and multiply in a rounded body called sporangia.

Ovary, style and stigma are female reproductive parts, whereas anther and filament are male reproductive parts. Male gametes, i.e. pollen grains are produced in anther lobes.

Flowers which bear both male and female reproductive parts, i.e. stamen and pistil are known as bisexual flowers. For example, mustard, rose and petunia are bisexual flowers.

After fertilisation, the ovary grows into a fruit and ovules develop into seeds. The seeds contain an embryo enclosed in a protective seed coat.

There are some flowers which contain either only pistil or only stamen. These flowers are known as unisexual flowers as only one sex is present in the flower. For example, corn, papaya, cucumber etc.

These are small flowerless plants.

It is also a type of twisted aestivation. In this type the perianth lobes overlap in such a manner that the margins of the two perianth lobes are completely inside, and the other two perianth lobes are outside, and in the remaining one perianth lobe, one margin is inside an the other margin is outside. Example: calyx of Ipomoea & Catharanthus.