Tag: basics of leaf and flower

A small leaf-like appendage on each side at the base of the petiole in dicotyledons is called as a stipule. The arrangement and structure of the stipules are called as the stipulation. When the pair of stipules is arranged freely on either side of the petiole or leaf base, it is called as free lateral stipules. For example, Hibiscus and Gossypium. 
Therefore, the correct answer is option D.

Stigma is the part of the female reproductive part in flower where the pollen grain lands after pollination. It is the one who decides the compatibility of pollen with the plant and it is sticky so that is able to hold the pollen strongly.

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.

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.