Brush rabbits require dense bramble clumps or other thick brushy habitat. When not flowering plants grow less than tall, forming clumps of sprawling foliage. It tends to form large clumps from thick, creeping rhizomes. Random distributions exhibit chance clumps (see Poisson clumping). Lungworts are evergreen or herbaceous perennials that form clumps or rosettes. The kauri has a habit of forming small clumps or patches scattered through mixed forests. The unbound tau clumps together in formations called neurofibrillary tangles. It is a rhizomatous herbaceous perennial producing clumps of stiff, squared stems tall. There are also stellate hairs on the underside of the leaf that grow in clumps. These occur in small clumps scattered in a more or less open form. When leaves appear, divide in large clumps. It has a colonial nature and often reproduces by root sprouting, forming clumps or thickets. Feeding cover&colon; scaled quail use grass clumps and shrubs for cover while feeding. Down forms clumps if exposed to dampness or moisture, and will mildew if left damp. They "found several instances of gorillas throwing sticks and clumps of grass".