Isoetaceae

Spore-producing fern allies that are usually aquatic and rooted under water but may emerge on shores when water levels drop. Their tufts of awl-like leaves resemble short tufts of grass.

Spore-bearing structures are located as swellings at the base of the leaf and can be felt when this part of the plant is gently squeezed. There are 2 types of spores, large ones (megaspores) and tiny ones (microspores), each type borne in a separate structure. High magnification under a microscope is required to reveal the ornamentation on the spores, and identification is largely based on spore size and pattern of ornamentation, as well as laboratory tests.

Leaves highly variable in shape (straight to coiled), texture (stiff and brittle to lax and flexible), and colour (bright green to reddish); these characteristics often influenced by environmental conditions. Stem (corm) is very short, fleshy, two-lobed, covered in leaf bases and located underground.