What field of study focuses on fossil pollen grains and spores?

The field of study that focuses on fossil pollen grains and spores is palynology. This specialized branch of biology examines pollen and spores from modern and ancient plants to interpret ecological and evolutionary trends. Palynologists analyze these microscopic particles to provide insights into past climates, vegetation, and ecological changes over time.

Paleoecology, while related, generally encompasses a broader scope, examining how ecosystems have changed over geological timescales, often using data from various sources, including palynological evidence. Phytology refers to the study of plants in general, which may include aspects of botany but does not specifically address pollen and spore analysis. Botany is the broad scientific study of plants, covering their physiology, structure, growth, and classification, but does not focus specifically on fossilized forms like palynology does. Thus, the precise nature of palynology as it pertains to fossil pollen grains and spores makes it the most accurate answer.