Botany and Plant Science

Commelina benghalensis, commonly known as the Benghal dayfloweris a perennial herb native to tropical Asia and Africa. These show cleistogamy. Cleistogamy or automatic self-pollination describes the trait of certain plants to propagate by using non-opening, self-pollinating flowers. Virtually all plants that produce cleistogamous flowers also produce hasmogamous ones. The principal advantage of cleistogamy is that it requires less plant resources to produce seeds because development of petals, nectar and large amounts of pollen are not required. This efficiency makes cleistogamy particularly useful for seed production on unfavorable sites or adverse conditions. The obvious disadvantage of cleistogamy is that self-fertilization occurs, which may suppress the creation of genetically superior plants.Therefore, the correct answer is option A.

In Tagetes the flowers are centripetally arranged. Tagetes species vary in size. Most species have pinnate  green leaves. Blooms naturally occur in
golden, orange, yellow, and white colors, often with maroon highlights. Floral heads are typically with both ray florets and disc florets.

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). Hence it is also called as a complete or perfect flower.

Flowers in which both male and female parts are present are called as bisexual flower. Hibiscus and mustard are examples of bisexual flowers. 

Sterilitzia reginae is the botanical name of the bird of paradise flower. It is called so because of the resemblance of its flowers to birds-of-paradise. In South Africa, it is commonly known as a crane flower.

actinomorphic flower - star shaped or radial- that can be divided in to two identical parts by a plane passing through the center. and is represented by a plus sign contained within a circle.

Hypogynous flowers have the gynoecium situated at the highest position on the thalamus. Among the listed plants, mustard, brinjal, china rose, lupin, gram, bean, chilli, petunia, tomato, and withania are hypogynous, totaling ten.

In floral formulas, a zygomorphic (bilaterally symmetrical) flower is represented by the percent symbol (%), while an actinomorphic (radically symmetrical) flower is represented by a circle with a plus sign or an asterisk symbol.

An incomplete flower is defined as a flower that lacks one or more of the four standard floral whorls, which are calyx, corolla, androecium, and gynoecium.

In a hypogynous flower, the gynoecium occupies the highest position while the other floral parts are inserted below it, and the thalamus is typically conical or convex shaped.

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). Hence it is also called as a complete or perfect flower. 

Unisexual flower is the one that possesses either stamens or carpels but not both.
Flowers give rise to fruit and seeds.
Thus, the correct answer is option (B), 'Unisexual flowers possess both stamen and pistil'.

After fertilization, the ovary of the flower usually develops into the fruit. Fruits are generally associated with having a sweet taste; however, not all fruits are sweet. The term "fruit" is used for a ripened ovary. In most cases, flowers in which fertilization has taken place will develop into fruits, while unfertilized flowers will not. The fruit encloses the seeds and the developing embryo, thereby providing it with protection. Flowers are bisexual only sometimes. Only some flowers take part in sexual reproduction. Flowers are produced only by angiosperms. 

Flowers are zygomorphic in Gulmohar. Zygomorphic flowers are the flowers which can be divided in one particular plane into two equal halves. The other examples of zygomorphic flowers are pea, bean etc. 

The receptacle is flattened at the top and bears numerous sessile flowers in centripetal order in Capitulum. A capitulum or head, the characteristic inflorescence of the sunflower family (Asteraceae). Depending on the tribe, the inflorescence may consist of ray flowers, disk flowers or both ray and disk flowers. The ovary of each flower is situated below the attachment of the corolla and stamens, a condition referred to as epigynous or inferior. Sunflower bear one or several to many wide, terminal capitula (flower heads) with bright yellow ray florets at the outside and yellow or maroon disc florets inside. Several ornamental cultivars have red-colored ray florets capitulum can be used as an exact synonym for pseudanthium and flower head, however its use is generally but not always restricted to the Asteraceae family. At least one source defines it as a small flower head. Flower head is a special type of inflorescence in which anything from a small cluster to hundreds or sometimes thousands of flowers are grouped together to form a single flower-like structure. Pseudanthia take various forms. The individual flowers of a pseudanthium commonly are called as florets.
Therefore, the correct option is D.