In some members of which of the following pairs of families, pollen grains retain their viability for months after release?

To answer the question, we need to identify the families in which some species have pollen grains that stay viable for several months after they are released.

Step 1: Review the characteristics of the four families listed.

• Poaceae (the grasses) – pollen is typically small and light, designed for rapid dispersal by wind. In most grasses, pollen viability is short, usually lasting only a few days because the grains desiccate quickly.

• Solanaceae (nightshades) – pollen is generally adapted for insect pollination. While some solanaceous species have relatively long‑lived pollen, it still rarely exceeds a few weeks.

• Rosaceae (the rose family) – many members, such as certain fruit trees (apple, cherry, quince), produce pollen that remains viable for many weeks, even up to several months, especially under cool, dry storage conditions.

• Leguminosae (the legume family) – several legumes (e.g., beans, peas, clover) are known to produce pollen that can stay fertile for months, particularly when the pollen is kept in a dry, cool environment.

Step 2: Compare the longevity of pollen across the families.

Both Rosaceae and Leguminosae contain species with documented long‑term pollen viability (months). In contrast, pollen from Poaceae and Solanaceae** generally loses viability within days to a few weeks.