[Image:Trilete spores.png|thumb|A late Silurian sporangium bearing trilete spores. Such spores are the earliest evidence of life on land. Green: A spore tetrad. Blue: A spore bearing a trilete mark – the -shaped scar. The spores are about 30–35 μm across.]] Palynology is the "study of dust" (from Greek παλύνω, palunō, "strew, sprinkle" and -logy) or "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposits including sediments of any age. The condition and identification of those particles, organic and inorganic, give the palynologist clues to the life, environment, and energetic conditions that produced them.