Platycerium wallichii
butterfly staghorn fern

How to recognise it

• Fertile fronds like open wings: broad, fan-shaped and prominently veined, split at the base into three uneven lobes, one long and one short, with the small outer lobe sterile.
• Two large spore patches: in the first sinus of the two main lobes, second only to elephantotis in width.
• Tall, crowned shields: cut three to five times into a crown.
• A real rest: in winter the shields brown out completely and the fertile fronds curl inward. It looks dead; it is dormant.
• Telling it from alcicorne: some overseas material also calls the African alcicorne a butterfly staghorn; in Taiwan that name is reserved for wallichii. Wallichii is single-bud, rests in the dry season, has crown-lobed shields and spore patches in the sinus; alcicorne is multi-bud, never truly rests, has round entire shields and spore patches near the tips of the segments.

Native habitat

Platycerium wallichii grows as an epiphyte in monsoon forest from north-east India (Assam) and Bangladesh through Myanmar, northern Thailand and Vietnam into southern Yunnan, at roughly 200–1000 m. It is the only staghorn fern native to mainland China and is a Class II protected plant there. The home climate has a hard dry season from about November to February, during which the plant sheds its fronds and rests; the monsoon brings it back.

Light

Bright, filtered light, shaded about 50% in summer. Give it full light in the growing season so the shield crown stands up; light matters little while it rests.

Water and humidity

In growth (spring to early autumn) it is thirsty: soak when the moss is just dry, at 60–80% humidity. Once it rests, cut water hard and keep the moss barely damp, like a wrung-out towel, neither soaked nor bone dry. Growers disagree about whether to allow the rest at all: some withhold water and let it sleep, others keep it slightly moist all year to prevent dormancy. Either way, never water a resting plant as if it were growing.

Medium and mounting

A single-bud species, generally regarded as non-pupping or nearly so, and raised from spores. The shields are tall and upright with a lobed crown, so use a long board; a high proportion of sphagnum moss but with sharp drainage, because a permanently wet crown rots.

Temperature and seasons (temperate, indoor)

Ideal 20–30 °C. Below about 15 °C growth stops, the shields brown out completely and the fertile fronds curl inward: that is dormancy. Keep it above 10 °C, away from cold draughts, and almost dry. Some sources report that sustained heat above 32 °C also stalls it, so ventilate in summer. Resume normal watering only when a new green shield emerges from the centre in spring.

Common problems

• All shields brown and fertile fronds curled in winter: dormant, not dead.
• Watering through dormancy: crown rot, the most common way to lose it.
• No sign of life in spring: check that the growing point is still green and wait until April or May.
• Spores fail to germinate: they are green and short-lived, sow them soon after collection.

Collector notes

Mother-plant expression. Judge by the spread and symmetry of the fertile fronds and by how completely the plant returns after its rest.

Propagation. Spores. Every plant is raised from a sporeling, and sporelings vary visibly in frond width and depth of lobing.