Lyngbya Agardh ex Gomont

Lyngbya has unbranched filaments that are straight, slightly wavy, or rarely coiled, and usually form large, layered, leathery mats of varied thickness. The filaments are cylindrical and usually wider than 6 µm. The cells are shorter than they are wide and may have a restricted cell wall. The apical cells often have a thickened cell wall called a calyptra.
A few planktonic species have gas vesicles for bouyancy, but most do not.
A rigid, distinct mucilage sheath is always present. The mucous can be thin or thick, and is colorless or slightly red, yellow-brown, or occasionally blue. Very rarely, false branching may form. Under extreme conditions the trichomes may leave the sheaths. Lyngbya is very similar to Phormidium, which has a looser sheath, and to Oscillatoria, which normally lacks a sheath. These three genera can be very difficult to distinguish.
Note the rigid, distinct mucilage sheath surrouding these Lyngbya filaments, indicated by the arrow.
A variety of epiphytic diatoms and other algae are living attached to the mucilage.
This sample was collected from a freshwater pond.