Java Fern 'Sp. Borneo'

Java Fern 'Sp. Borneo' (Microsorum pteropus sp. 'Borneo') represents a wild-collected variant originating from the island of Borneo, distinct from horticultural cultivars by virtue of its natural provenance. It produces particularly leathery, darkly coloured fronds with pronounced venation — qualities that developed as adaptations to the strong currents and variable lighting of Borneo's riverine environments.

This form is highly valued by aquarists creating Southeast Asian biotope aquascapes — especially those replicating the blackwater or clearwater streams of Kalimantan or Sarawak. Its robust rhizome anchors firmly to submerged wood and rock in high-flow conditions, and its dark, rich colouration provides an especially natural appearance.

Care is straightforward and identical to standard Java Fern: attach to hardscape, provide low to moderate light, and fertilise regularly. This variant is slightly slower-growing than some cultivars but produces impressive, long-lived fronds that develop sori (spore patches) on their undersides as the plant matures.

Light: Low; wild-type forms adapted to dappled, low-intensity forest stream lighting — 15–35 µmol PAR is ideal. CO2: Not required; grows naturally in CO2-rich but low-oxygen blackwater streams. Fertilisation: Liquid trace elements and micronutrients weekly; additional iron supports the deep-green leaf pigmentation. Placement: Tie or glue rhizome to large driftwood in midground or background; suits high-flow biotope setups. Propagation: Detach rhizome offshoots or leaf-margin plantlets once well established.