AP BIOLOGY

Detailed explanation-1: -Stamen: The pollen producing part of a flower, usually with a slender filament supporting the anther. Anther: The part of the stamen where pollen is produced. Pistil: The ovule producing part of a flower.

Detailed explanation-2: -These stamens are filamentous structures that support the anther that produces the pollen grains. These anthers have two lobes and are termed bilobed anthers. The transverse section of the anther helps to distinguish this bilobed structure. The two lobes of the anther are formed by a septum.

Detailed explanation-3: -The top of the pistil is called the stigma, which is a sticky surface receptive to pollen.

Detailed explanation-4: -The anther consists of four saclike structures (microsporangia) that produce pollen for pollination. Small secretory structures, called nectaries, are often found at the base of the stamens; they provide food rewards for insect and bird pollinators.

Detailed explanation-5: -In angiosperms, pollen is produced by the anthers of the stamens in flowers. In gymnosperms, it is formed in the microsporophylls of the microstrobili (male pollen cones). Pollen consists of one or more vegetative cells and a reproductive cell. A pollen grain itself is not the male gamete.