It prefers soft substrates and surrounds its shell in a dense mass of byssus.

The stipe base features a dense mass of whitish rhizomorphs embedded with needles and other forest debris.

The resulting air pollution was trapped by the inversion layer formed by the dense mass of cold air.

The chromosomal material in the nucleus of mitotically dividing oogonia shows as a dense mass surrounded by vesicles or double membranes.

The large flower panicles do not open but remain inside their leaf sheaths forming a dense mass.