#eriocaulon

Eriocaulon quinquangulare

Also known as Eriocaulon sp. 'King Crimson' and Eriocaulon sp. 'Red India'. Among the few plants from the family Eriocaulaceae kept in planted aquaria, it is the only red one, making it demanded and expensive. Like most other Eriocaulon it a very peculiar plant: The Eriocaulon quinquangulare grows in (hyper-)oligotrophic lakes and wetlands submersed in a swallow depth or emersed, thus it has odd strategies of accquiring nutrients, especially Carbon. It is an extremely heavy rooting plants that can grow three times as much root mass as any other biomass and these roots all have a very high oxygen loss, so it oxygenates the soil and thus allows aerobe decomposition to release CO₂ which is also uptakes over the roots [1]. This nearly unique C uptake mechanism is limited to the so called Isoetids, a superficial groups at encompasses most Eriocaulon species and a few more. However, this comes with a hefty price: They cannot use HCO₃- for photosynthesis in the interestingly CAM-like metabolism. CAM is the water-saving metabolism of succulents and not what one would expect in an aquatic plant.

My Isoetids .

Isoetids are plants that superficially resemble Isoetes species. They are more or less spiky rosette plants from low-nutrient environments that have odd characteristics for aquatic plants, such as extremly large root networks, sometimes even trice as massive as their foliage by dry weight. Many can do CAM photosynthesis, which is typically for water conserving plant such as succulents and seemingly out of place for an aquatic plant or an wet land plant. Interestingly, they have a very oxygen loss through their roots, meaning they are excellent at aerating the substrate, which allows easier nutrient uptake and leads to suprised aquarists when they see their substrate bubbling.

I've just noticed that there is an exterme lack content for aquatic plants of the genera Eriocaulon and Syngonanthus!