Platycerium
Platycerium stemaria
triangle staghorn fern
- Latin
- Platycerium stemaria
- Chinese
- 三角鹿角蕨
- Japanese
- ステマリア
- English
- triangle staghorn fern
Platycerium stemaria, the triangle staghorn fern, is a West and Central African epiphyte with tall shield fronds whose wavy tops flare outward, and short, broad fertile fronds that are glossy above and thickly felted white beneath. It pups freely, likes water and heat, and is one of the easier African species in a warm climate.
Care notes
Native habitat
Platycerium stemaria grows as an epiphyte in the lowland rainforest of West and Central Africa, from the Gulf of Guinea into the Congo basin. Kew also lists Madagascar, the Comoros and the Seychelles in its range; most growers only recognise the mainland form, and the question is not settled. The home climate is warm and humid all year under a filtered canopy, which makes this the thirstiest of the African staghorn fern species.
Light
Bright, filtered light. Shade it 50–70% in summer; direct midday sun scorches the broad fertile fronds and curls the wavy crown of the shield. Move it brighter in winter.
Water and humidity
It likes water. Soak when the surface of the moss dries, roughly every three to four days in summer. Aim for 60% humidity or more. In dry moving air the fertile fronds roll inward to save moisture; they open again after a soak. Keep standing water out of the nest.
Medium and mounting
Temperature and seasons (temperate, indoor)
Ideal 20–30 °C. It enjoys a warm summer outside in shade, and in a temperate home it is strictly an indoor plant from autumn. Growth stops below about 15 °C; keep it above 10 °C and reduce water in winter. It is less cold-tolerant than P. bifurcatum.
Common problems
- Fertile fronds curling inward: dry air or under-watering, not disease.
- Brown tips on the shield crown: too much sun.
- No growth in winter: cold check, cut water and wait for spring.
- White fuzz under the fertile fronds: normal, the dense felt is a hallmark of the species.
Collector notes
Identification. Tall shields with a wavy, flared top that leave a V-shaped gap where two meet; short, broad fertile fronds, glossy dark green above and thickly felted white below, splitting into one large and two smaller lobes with the spore patches concentrated on the undersides of those smaller divisions. P. elephantotis, the other broad-fronded African, has unforked fertile fronds with no felt beneath.
Mother-plant expression. Judge by an even wave along the shield crown, a symmetrical V, and the width and thickness of the fertile fronds.
FAQ
How do I identify Platycerium stemaria?
Look at the shield crown and the underside of the fertile fronds. Shields are tall with a wavy, flared top that leaves a V-shaped gap between the pair; fertile fronds are short and broad, glossy above and thickly felted white beneath, splitting into one large and two smaller lobes. The triangle in the name refers to that outline.
Does Platycerium stemaria produce pups?
Yes. It is a multi-bud species and mature plants throw pups around the base. Leave them for a clump, or separate them once a pup has three or more fronds. Spores work too, and sporelings vary noticeably in shield height and wave depth.
Why are the fertile fronds on my Platycerium stemaria curling inward?
Dry air or under-watering. This is the thirstiest of the African species, and its fertile fronds roll inward to hold moisture when they dry out. Soak the mount and raise the humidity and they open again. A fan blowing straight at the plant is the usual cause; move it out of the draught.
How cold can Platycerium stemaria tolerate?
Growth stops below about 15 °C and it needs protection below 10 °C. Keep it out of cold draughts and reduce watering in winter; sporelings and freshly mounted plants come indoors. It is less hardy than P. bifurcatum, but established plants cope with a cool room as long as they are not cold and wet.
What is the difference between Platycerium stemaria and P. elephantotis?
Both are African with broad fertile fronds, but elephantotis has unforked fertile fronds with no felt beneath, while stemaria's split into one large and two smaller lobes and are thickly felted white underneath. Stemaria's shields also flare into a wavy top; elephantotis shields are rounder and thicker.