Dawsonia (plant) lamella – chains of small cells on the upper surface of the leaves analogous to the mesophyll cells of vascular plant leaves. They increase the surface area of cell walls available for CO uptake, while at the same time maintaining layers of moist air between lamellae, reducing water loss. Lamella margins have a surface wax layer which prevents water from flooding into the interlamellar spaces. Dawsonia (plant) Dawsonia is a genus of acrocarpous mosses. "Dawsonia", along with other members of the order Polytrichales, are taller than most mosses and have thicker leaves. Their sporophytes have conducting systems analogous to those
Glossary of plant morphology from roots to overhead structures, for water and other growth-enhancing substances. These conduits consist of specialised tissues known as vascular bundles, which give the name "vascular plants" to the angiosperms. The point of insertion, on the stem, of leaves or buds is a node, and the space between two successive nodes, an internode. The leaves, which emerge from the shoot, are specialised structures that carry out photosynthesis, and gas (oxygen and carbon dioxide) and water exchange. They are sheathed by an outer layer or epidermis that is coated with a waxy waterproof protective layer, which is punctuated by specialised pores,