Isoetes lacustris

See quillwort ( Isoetes lacustris ) (A) Whole plant - (1 ) leaf base with sporangium at the base and ligule about - (2 ) longitudinal section and (3) cross -section of the sheet substrate with the chambered sporangium - (4 ) cross-section through shoot base

The lake quillwort ( Isoetes lacustris ) is a European species of the genus Brachsenkräuter ( Isoetes ), a systematically isolated standing group of Bärlapppflanzen. It is an aquatic plant.

Features

The lake quillwort, like all members of the genus, a perennial plant and has a straight, compressed, bulbous stem axis, showing secondary growth. At the axis is a rosette of bins shaped leaves. The leaves are terete, 8-25 (rarely 40) mm long and 2-3 mm wide. They are dark green, stiff and short acuminate. The plants reach stature heights of 3 to 15 cm.

The sporangia are in a pit at the base of scheidig expanded leaves. The macro - and Mikrosporophylle are alike, the former stand outside on the bezel, the latter inside. The macro spores have a tight kleinhöckerige surface and a diameter 530-700 microns. The spores ripen from July to September.

The prothallus is unisexual, short-lived and remains in the spore. The spermatozoids are vielgeißelig.

The species is dekaploid.

Dissemination and locations

The lake quillwort occurs in the west, north and east of Europe, in Central Europe it is rare. Furthermore, it still happens in North America.

In Germany the species is endangered nationwide, in some states it is already extinct. In Austria does not come and she came before, older data on reserves in some Salzburg lakes are " probably by mistake ." From Switzerland, only three find areas in the Central Alps are known which stocks are decreasing as stable to slightly.

The lake quillwort growing submerged ( submerged ) in nutrient-poor ( oligotrophic ) and calcium-poor cold water lakes with sandy or gravelly ground and plant communities of the class Littorelletea, so the beach Nerd companies assign. It comes down to five, rarely up to eight meters of water depth before.

Documents

• Siegmund Seybold (ed.): Schmeil Fitschen - interactive ( CD -Rom ), Quelle & Meyer, Wiebelsheim 2001/2002, ISBN 3-494-01327-6