A microscopic air sac within a pulmonary alveolus.
An upper chamber of the heart that receives blood from the veins and forces it into a ventricle. In higher vertebrates, the right atrium receives blood from the superior vena cava and inferior vena cava, and the left atrium receives blood from the left and right pulmonary veins.
A cavity inside a porate aperture of a pollen grain formed by the separation of the sexine and nexine layers, widening toward the interior of the grain.
A cavity, entrance, or passage.
A central room or space in ancient Roman homes, open to the sky in the middle; a similar space in other buildings.
Any enclosed body cavity or chamber.
A square hall lit by daylight from above, into which rooms open at one or more levels.
Pulmonaria angustifolia, blue cowslip or narrow-leaved lungwort
Primula deorum, a flowering plant known as God's cowslip and rila cowslip
A low-growing plant, Primula veris, with yellow flowers.
Primula florindae, a flowering plant known as giant cowslip and Tibetan cowslip
marsh marigold, Caltha palustris, a plant in the buttercup family, growing in wet, boggy locations.
Primula sikkimensis, a flowering plant known as Himalayan cowslip and Sikkim cowslip