Pilularia
Usually Pillenfarn from Thomé: Flora of Germany, Austria and Switzerland
The pill ferns ( Pilularia ) are a genus of ferns from the family of Kleefarngewächse in which the leaves are bins like thready. They are sometimes placed in a separate family Pilulariaceae.
Description and habitat requirements
The plants live aquatic in shallow water, sometimes on open muddy ground, but at least to temporarily flooded sites. Like all Kleefarngewächse they form a long, crawling on the ground rhizome, which branched dichotomously. At the nodes of the main axis spring roots.
The rhizome of the upwardly projecting fronds have no leaf blade, but are more or less thread-like or bins shaped. A result, the plants have a grass-like habit, but can be distinguished from grasses by the rolled-up young fronds.
The dark brown Sporokarpien sit side next to the head of short, underground and unbranched lateral branches that originate at the base of the leaves. Typical of the type is that the only two to four Sporokarpien sori contain, in turn, contain microsporangia and macrosporangia. At fruit maturity, the Sporokarp opens with two to four flaps, depending on the number of sori, and dismisses its contents embedded in a gelatinous drop in which to grow the gametophytes and fertilization takes place.
From the shape of the Sporokarpe, reminiscent of pills, also the German and the scientific name of the genus is derived.
Types and distribution
The genus consists of six species with strong disjunktem area:
- American Pillenfarn ( Pilularia americana A. Braun ), a species that is closely related to the ordinary European Pillenfarn, and their distribution in turn consists of three disjunct areas in the west, in the central and eastern parts of North America.
- Usually Pillenfarn ( Pilularia globulifera L.), from the Atlantic Western and Central Europe
- Small Pillenfarn ( Pilularia minuta Durieu ex A. Braun), from the Mediterranean region of Morocco and Portugal to Cyprus and Turkey. It differs from the ordinary Pillenfarn through the leaves that are less than 4 cm long, the Sporokarpien with only 2 chambers and a diameter < 1 mm.
- Bolivian Pillenfarn ( Pilularia mandonii A. Braun ); it grows in 5000m altitude in the Bolivian Andes.
- Australian Pillenfarn ( Pilularia novae- hollandiae A.Braun ), a species in Australia and Tasmania.
- New Zealand Pillenfarn ( Pilularia novae- zealandiae Kirk), a New Zealand Art