Isoetes velata var. sicula

Description

Isoetes species, known as quillworts, reproduce through spores like ferns. They belong to an ancient group of Lycophytes and are closely related to extinct tree species from the Palaeozoic era. There are around 60-150 Isoetes species worldwide, typically growing on wet ground or in water. Some suitable aquarium plant species include I. malinverniana, I. japonica, and I. velata var. sicula. I. velata forms a dense rosette of grass-green leaves that grow 10-30 cm long on an up to 2 cm high bulbous rhizome. It grows slowly but is adaptable to various water parameters. A nutrient-rich substrate, such as sand or fine gravel mixed with loam, is recommended. Propagation by spores is complicated and requires mixing macro- and microspores in water before sowing onto a moist substrate. In contrast to true ferns, Isoetes lacks prothallia and instead releases spermatozoids through the water to fertilize egg cells. The fertilized egg cell develops into a young Isoetes plant that initially feeds on stored nutrients and later is thinned out.