Microsorum sp. 'Borneo'

Microsorum sp. 'Borneo' is an undescribed or informally classified Microsorum species collected from the island of Borneo, where it grows submerged or emergent along forest streams and river margins. It produces bold, somewhat undulating fronds with a deep, rich-green colour and prominent venation that gives it a more rugged appearance than the standard Java fern. Fronds typically reach 25–35 cm, making it a substantial midground to background plant.

This species is less commonly available than Java fern cultivars but is increasingly sought after by specialist aquascapers and biotope enthusiasts. Its care is broadly similar to other Microsorum — attach to hardscape, provide low-to-medium light and stable water quality. It is somewhat less tolerant of hard water than the standard Java fern and performs best in soft to moderately hard conditions. CO2 supplementation significantly improves growth and frond quality in this species.