Acystopteris taiwaniana

 Taiwanese Bladder Fern Cystopteridaceae

Acystopteris taiwaniana is a choice little-known Taiwanese fern, and one for the connoisseur rather than the mass-market fern department. Endemic to Taiwan, it occurs in humid mountain forests and valleys at approximately 1,600–2,600m, with specimens recorded at almost 3,000m. Its creeping rhizome produces delicate, broadly triangular to ovate fronds, typically 2–3-pinnate, with chestnut-brown stipes and rachises and a particularly attractive, finely textured appearance. 

In cultivation, give it cool, shaded conditions, preferably in humus-rich, moisture-retentive soil with excellent drainage. Its montane origins suggest that keeping the root zone cool and evenly moist is more important than feeding heavily. Avoid hot, dry positions, where this refined mountain dweller is likely to stage a rather rapid disappearance.

It is a particularly interesting fern for a specialist collection, combining the delicate appearance of a Cystopteris with a surprisingly substantial mature frond. The species was originally described as Cystopteris japonica var. taiwaniana, before being transferred to Acystopteris in 1977. 

Altitude: 1,600–2,600m
Hardiness: H5, approximately −15 to −10°C
Height: 35–80cm
Spread: 40–60cm