Rhizome creeping, irregularly branched, up to 0.5 mm in diameter, with unbranched roots or root clusters at the nodes, internodes up to 11 mm long, initially sparsely hairy, smooth with age, mostly with a few laterally attached small hairs at the frond base. Fronds with single unbranched stele, borne singly at nodes, erect, simple, terete, up to 19 mm long, basally with a few laterally attached very small hairs, hairless higher up. Sporocarps globose, up to 2.5 mm in diameter, laterally attached, with 4 sori, densely set with small hairs, epigeus at maturity, pedicel arises at rhizome node, up to 2 mm long, initially growing downwards, twisted and burying the sporocarps in the substrate. Microsporangia clavate, several per sorus, wall one cell layer thick, hyaline, each bearing 23-32 microspores. Megasporangia globose, wall one cell layer thick, 8-17 per sporus, each bearing a single megaspore.

It is more than likely that the Ethiopian population concerns a different species of Pilularia. This is based on the description of a new species for the South African population originally included under P. americana A.Braun (Roux 2002). It is, however, not known to me if a new species has been described yet for the Ethiopian population.
Ethiopian species have 4 sori in the sporocarp, European ones have 2. The oldest legitimate name for the species complex has been chosen until its taxonomy is better understood (Hedberg et all, 2009).

Along edge of small lakes in afroalpine Helichrysum heath in Bale Mountains.

Africa, North and South America.

Ethiopia.

Aquatic.