Botany and Plant Science

• A flower is a reproductive structure of a flowering plant, which is a morphological and embryological marvel and the site of sexual reproduction.
• Anther is attached to the distal end of the filament of the stamen.
• Androecium (stamens) and gynoecium (pistils) represent essential parts of a flower.
• The number and length of stamens are variable in flowers of different species.

Calyx and corolla are called as accessory whorls. In some plants they are not differentiated from one another, in such case they are termed as perianth.

Stamens are numerous, epipetalous and monadephous. The filaments of all the stamens fuse to form staminal tube, round the style is a characteristic feature of family Malvaceae.

Achlamydeous flowers are those flowers that lack floral envelope. these flowers are also referred to as naked flowers.

A bisexual flower is a flower that contains all the four whorls such as petals, sepals, the male reproductive structure (stamen) and female reproductive structure (pistil/ carpel). Hence it is also called as a complete or perfect flower. Petunia is a bisexual flower. Thus the correct answer is option A.

The flower is a reproductive organ of an angiosperm plant. The typical flowers consist of sepals, petals, stamens, and carpels. A flower having both stamens as well as carpels or pistils is known as a bisexual flower. Flowers that are either staminate (means having stamens) or pistillate (having pistils only) are known as unisexual flowers. Thus the answer is bisexual flowers.

The correct option is A.

Night-blooming flowers rely on nocturnal pollinators like moths and bats. To attract these pollinators in the dark, they typically emit strong scents rather than relying on bright colors.

The perianth is the outermost whorl of a flower which consists of sepals and petals but they are not differentiated. The perianth is represented by membranous scales known as lodicules. The lodicules are situated above and opposite to the superior palea. The number or lodicules maybe 2 or 3 or many or they may be absent. 

• Pollen grains represent the highly reduced haploid male gametophyte generation in flowering plants, consisting of just two or three cells when released from the anthers. Their role is to deliver twin sperm cells to the embryo sac to undergo fusion with the egg and central cell.
•  The female gametophyte of flowering plants, which produces the two female gametes – the egg cell and central cell – for double-fertilization by the two sperm cells of the male gametophyte
  

Unisexual flowers are those which have either the stamen or pistil but never both.
However, Hibiscus has both male and female reproductive organs as stamen and pistil, in the same flower and hence is not unisexual, it is in fact, bisexual.
Thus, the correct answer is option (A).

Monoecious plant species have separate male and female flowers on the same plant. Examples or monoecious plants are maize, birch, coconut and cucurbit. The plants in which male and female flowers are borne on separate individual are referred to as dioecious plants. e.g., papaya, date palm.

Autogamy is possible only when anther and stigma are close together and there is synchrony in pollen release and stigma receptivity. As in case f cleistogamous flowers, the flowers remain closed so that anthers and stigmas are never exposed. The flowers undergo only self pollination. No external pollinating agency is required.

In Cyathium inflorescence, stamen represents the male flowers and pistil represents a female flower. This type of inflorescence is characterized by the presence of several male flowers (stamen) around a pistillate flower. Cyathium inflorescence is the characteristic feature of Euphorbia genus.

Perianth is represented by membranous scales called as lodicules, they may be 2 or 3 and also interpreted as relictual perianth.