Introduction & Discovery

Cyathea tricolor is a visually arresting Brazilian tree fern whose epithet, from the Latin tri (three) and color (colour), describes the distinctive polychromatic pattern that unfolds along its fronds. Where most tree ferns present a relatively uniform green aspect, C. tricolor displays a striking interplay of colours across the stipe, rachis, and lamina, with the stipe typically one shade, the rachis or costae contrasting, and the pinnule tissue a third hue. This three-toned effect, which may involve combinations of dark brown or purplish stipe bases, lighter brown to green rachis, and the green of the lamina, creates an ornamental quality that has drawn the attention of fern growers and botanical artists. Native to the Atlantic Forest of southeastern Brazil, C. tricolor belongs to the assemblage of tree ferns that have diversified in this ancient, species-rich biome. The Atlantic Forest, which stretches along the Brazilian coast and once covered approximately 1.3 million square kilometres, has been reduced to roughly 12 percent of its original extent by five centuries of agricultural and urban expansion, making species endemic or largely confined to this biome of urgent conservation concern. The species develops an erect caudex of two to six metres, bearing a crown of arching bipinnate fronds of up to three metres. The trunk is the standard Cyatheaceae composite of adventitious roots and persistent stipe bases, with scales at the stipe base distinguishing the family from the hair-bearing Dicksoniaceae. In cultivation, C. tricolor is rare outside Brazilian collections but highly valued by specialists for its colour display. Like all Cyatheaceae, it is listed on CITES Appendix II. The Atlantic Forest tree fern assemblage to which C. tricolor belongs is one of the most diverse in the Neotropics, with over twenty species of Cyathea and Dicksonia recorded from this biome. This diversity reflects the great antiquity of the Atlantic Forest, which has existed as a distinct biome for tens of millions of years, its isolation from Amazonia by the dry diagonal of the Cerrado and Caatinga allowing independent diversification of its flora and fauna. The tree fern radiation in the Atlantic Forest has produced species adapted to a range of elevations and microhabitats, from the lowland restinga forests near sea level to the high campos de altitude above 2000 metres. Cyathea tricolor occupies the mid-elevation zone of this gradient, where rainfall is highest and temperature conditions are most equable. The three-colour character that defines the species is unusual among tree ferns globally; while many Cyathea species have dark or light stipe bases, the clear three-zone colour pattern spanning from stipe through rachis to lamina is distinctive. In the field, this character is most conspicuous when viewing a freshly mature frond from the side, where the colour transitions along the frond axis create a gradient effect that is both aesthetically pleasing and taxonomically diagnostic. Botanical artists have found C. tricolor a rewarding subject, as the colour pattern challenges the common perception that tree ferns are monotonously green. The significance of C. tricolor extends beyond its ornamental qualities to its role as a representative of Atlantic Forest biodiversity and a potential flagship species for conservation efforts. The charismatic colour display provides an accessible entry point for engaging the public with the broader conservation challenges facing the Atlantic Forest biome. When displayed in botanical garden conservatories or featured in educational materials, the species' visual distinctiveness captures attention in a way that can be leveraged to communicate the urgency of Atlantic Forest protection. The species also holds scientific value as a member of the Atlantic Forest Cyathea radiation, a group whose evolutionary history reflects the deep-time biogeographic dynamics of the South American continent.

Alsophila dealbata, commonly known as the silver fern or silver tree-fern, or as ponga or punga, is a species of medium-sized tree fern, endemic to New Zealand. The fern is usually recognisable by the silver-white colour of the under-surface of mature fronds. It is a symbol commonly associated with the country both overseas and by New Zealanders themselves.

Discovery & Naming

The epithet tricolor, from the Latin for three-coloured, was assigned to describe the distinctive polychromatic pattern of the frond axis. The species was described from Atlantic Forest material in southeastern Brazil. Like other Brazilian Cyathea, its taxonomy has been refined by the work of Paulo Windisch, Alexandre Salino, and other Brazilian pteridologists. The species belongs to the Atlantic Forest Cyathea radiation, a group that diversified in this ancient biome during its long isolation from Amazonia. The Atlantic Forest Cyathea radiation represents a major evolutionary diversification event, with the group having likely diversified over the past 15 to 25 million years as the Atlantic Forest biome underwent climatic fluctuations associated with Cenozoic cooling and warming cycles. During glacial periods, the Atlantic Forest contracted to refugia in the coastal mountains, where tree fern populations may have undergone allopatric speciation. The subsequent expansion during interglacial warm periods brought these newly differentiated species into secondary contact, producing the high sympatric diversity observed today.

Native Range & Distribution Map

Distribution map showing the native range of Cyathea tricolor.

Biology & Frond Morphology

Cyathea tricolor belongs to the genus Cyathea in the family Cyatheaceae, producing bipinnate to bipinnate-pinnatifid, arching fronds 1.5 to 3 metres long forming a spreading crown. blades are broadly lanceolate, herbaceous to subcoriaceous. the defining feature referenced by the epithet tricolor (three-coloured) is the distinctive colour pattern displayed across the frond architecture: typically the stipe is one colour, the rachis or costae another, and the laminar tissue a third, creating a striking tripartite colour scheme. stipe base scales may contribute additional colour contrast. pinnae are alternate, 25 to 50 centimetres long, and the interplay of colours along the frond axis makes this species visually distinctive. the colour contrast between stipe, rachis, and lamina intensifies with frond age, being most pronounced in fronds of six to twelve months age and fading somewhat as the frond approaches senescence. newly emerged fronds display the colour contrast most dramatically, as the fresh tissue has not yet been dulled by epiphyte colonisation or environmental weathering. the abaxial surface of the pinnules may show a slight glaucous bloom in some populations, adding a fourth subtle colour element. croziers are tightly circinate and clothed in deciduous brown scales during their emergence phase. fronds that unfurl from coiled fiddleheads (croziers). Like all ferns, it reproduces via spores borne on the underside of fertile fronds rather than flowers and seeds, and its life cycle alternates between a dominant sporophyte (the visible plant) and a small, short-lived gametophyte stage.

Reproduction & Propagation

Propagation of Cyathea tricolor can be achieved through several methods:

• Spores: Collect ripe spores from the underside of fertile fronds, sow on sterilised peat or peat/perlite mix. Do not cover. Keep humid and in bright indirect light. Prothalli (gametophytes) typically develop in 4–12 weeks, and young sporophytes appear after a further 2–6 months.
• Division: Mature clumps with multiple crowns or creeping rhizomes can be divided in spring as new fronds emerge.
• Rhizome cuttings / offsets: Epiphytic genera (Davallia, Polypodium, Phlebodium) can be propagated from 5–10 cm rhizome segments with at least one frond and visible roots.

Cultivation & Substrate

Successful cultivation of Cyathea tricolor depends on matching three conditions to its natural habitat: consistent moisture without waterlogging, a humus-rich yet well-drained substrate, and the correct light level for its frond type — whether dappled woodland shade, bright filtered light, or, for a handful of rock ferns, direct sun.

Common Mistakes to Avoid

Full sun damages the colour pattern and scorches fronds. Insufficient humidity causes frond decline. Crown flooding promotes rot. Using alkaline substrates causes nutrient lockout. Confusing the colour pattern with disease leads to unnecessary treatment. Contributing to the xaxim trade by purchasing wild-harvested trunk material is both ecologically harmful and legally problematic. Purchasing or using xaxim products made from wild-harvested tree fern trunks perpetuates an ecologically destructive trade and may violate Brazilian federal law. Growers should ensure any substrate material marketed as xaxim is either synthetic or derived from sustainably managed plantation sources with proper documentation. Overcrowding tree ferns by planting too closely together reduces air circulation around the crowns and creates conditions favourable for crown rot pathogens. Allow at least 2 to 3 metres between individual tree ferns to ensure adequate air movement and light penetration to each crown.

Seasonal Considerations

Southern Hemisphere: Spring (September to November): main growth flush. Resume feeding. Increase watering. Summer (December to February): deep watering, misting, monthly feeding. Autumn (March to May): reduce feeding, reduce watering. Winter (June to August): minimal watering, no feeding, frost protection. Adjust for Northern Hemisphere cultivation accordingly. In the Southern Hemisphere growing calendar, the main growth flush occurs from September through November, coinciding with increasing day length and rising temperatures after the austral winter. This is the most critical period for ensuring adequate moisture and fertility. Spore collection from the previous season's fertile fronds is best done in January to March, when sori are mature and before heavy summer rains wash away released spores.

Diseases & Pests

Common issues affecting Cyathea tricolor in cultivation:

• Root/rhizome rot: Caused by waterlogged substrate, compacted soil, or overwatering in cool weather. Ensure the growing medium is well-aerated and never let pots sit in standing water for prolonged periods.
• Fungal leaf spot & Botrytis: Brown or grey blotches appear in stagnant, overly humid conditions. Improve air circulation, remove affected fronds, and avoid wetting foliage late in the day.
• Scale insects & mealybugs: The most common fern pests, hiding on stipes and frond undersides. Wipe off with a cotton swab dipped in diluted isopropyl alcohol, or treat with horticultural soap. Many chemical pesticides scorch fern fronds — always test on one frond first.
• Spider mites: Fine webbing and stippled fronds, common in dry indoor air. Raise humidity and rinse fronds regularly with tepid water.
• Frond browning (tip burn): Caused by dry air, direct hot sun, fluoridated or chlorinated tap water (especially in Nephrolepis, Calathea-loving filmy ferns), or soluble-salt build-up from fertiliser. Flush the pot with rainwater and reduce feeding.

Indoor Growing & Terrariums

Cyathea tricolor can be grown indoors as a houseplant or terrarium subject when its humidity and light requirements are met.

Indoor Setup

• Light: Bright indirect light — an east- or north-facing window, or 30–60 cm under an LED grow light (10–12 hours/day). Most ferns scorch in direct midday sun.
• Humidity: 50–80%. Group plants, stand pots on a pebble-and-water tray, or run a humidifier; misting alone rarely raises ambient humidity enough.
• Temperature: 16–24°C (60–75°F) for most indoor species; avoid cold drafts and hot radiators.
• Substrate: Peat-free potting mix with added perlite and orchid bark for drainage; epiphytic genera (Platycerium, Davallia) grow best mounted on bark or in a bark-heavy orchid mix.
• Water: Keep consistently moist but never waterlogged. Let the top 1–2 cm of substrate dry slightly between waterings in winter.
• Air circulation: A gentle fan discourages fungal leaf spot without drying out the fronds.

Landscape & Garden Use

Cyathea tricolor can be used in the garden wherever its hardiness and habitat preferences are matched. Ferns are classic choices for shaded borders, woodland gardens, stumperies, rockeries, stream-side plantings, and ground-cover under trees.

Landscape Tips

• Companions: Hostas, Astilbe, Heuchera, Tiarella, Epimedium, hellebores, snowdrops and other shade-tolerant perennials are classic partners.
• Soil preparation: Incorporate leaf mould or composted bark to improve moisture retention and mimic a forest floor.
• Mulching: A 3–5 cm mulch of chipped bark or leaf litter protects the rhizomes, conserves moisture, and slowly releases nutrients.
• Watering: Establish new plantings with regular deep watering during the first growing season; most hardy ferns need only occasional supplemental irrigation once established.

Conservation & Collector Notes

Listed on CITES Appendix II with all Cyatheaceae. As an Atlantic Forest species, C. tricolor faces significant habitat loss from the reduction of this biome to approximately 12 percent of its original extent. Remaining populations are fragmented and largely confined to protected areas. Brazilian environmental legislation (Lei da Mata Atlantica) provides broad habitat protection. No formal IUCN assessment exists, but the species may qualify for Near Threatened or Vulnerable status based on ongoing habitat loss. Conservation priorities include Atlantic Forest protection, enforcement of anti-deforestation legislation, and maintenance of ex-situ collections. The xaxim trade, in which tree fern trunk material was commercially harvested for orchid-growing substrate, caused significant population declines across multiple Atlantic Forest Cyathea and Dicksonia species before regulatory intervention in the 1990s and 2000s. Brazilian federal law now prohibits commercial extraction of tree fern trunks from native forests, and synthetic xaxim substitutes are widely available. However, illegal extraction continues at a reduced level in poorly policed forest fragments. The species' survival depends on the integrity of the remaining Atlantic Forest fragments, many of which are too small to support viable populations without management intervention such as corridor creation to enable genetic exchange between fragments. Ex-situ conservation collections in Brazilian botanical gardens serve as insurance populations against local extinction events and provide material for research and educational programmes. The Jardim Botanico do Rio de Janeiro, the Instituto de Botanica de Sao Paulo, and the Jardim Botanico de Curitiba all maintain important living collections of Atlantic Forest tree ferns. International botanical gardens contribute to the global ex-situ conservation effort by cultivating Brazilian Cyathea species under CITES-compliant protocols.

Collector Notes

Cyathea tricolor is prized by collectors for its unique chromatic display among tree ferns. All Cyatheaceae are CITES Appendix II; valid documentation required. Ethical acquisition is through spore-raised material. Atlantic Forest provenance means material is scarce internationally. Fern society exchanges and Brazilian botanical gardens are the best sources. Display where the three-colour stipe-rachis-lamina pattern is visible. The species combines ornamental quality with conservation significance as an Atlantic Forest endemic. Notable collections include the Jardim Botanico do Rio de Janeiro and the Instituto de Botanica de Sao Paulo. The species' combination of ornamental appeal and conservation significance makes it a valuable flagship for Atlantic Forest awareness in international collections. Pairing C. tricolor with other Atlantic Forest endemics such as Euterpe edulis palm, Vriesea bromeliads, and Cattleya orchids in a themed display communicates the extraordinary biodiversity and precarious status of this biome to visiting public and students. Photographic documentation of the three-colour pattern at different stages of frond development provides valuable reference material for identification and for sharing with other collectors and researchers. The freshest colour display occurs on newly mature fronds, and capturing this with high-quality photography ensures a permanent record even as the frond ages and the colour intensity fades. Provenance records documenting the exact locality, elevation, and habitat of origin add scientific value to cultivated specimens.

Ethnobotany & Cultural Significance

Uses follow the general Atlantic Forest tree fern pattern. Trunk material has been used as xaxim substrate for orchid growing, contributing to historical population decline before regulatory restriction. Pith as food and young croziers consumed occasionally. The distinctive colour pattern has no specific recorded ethnobotanical significance. The xaxim industry, centred in the southern Brazilian states of Parana and Santa Catarina, was historically one of the largest commercial uses of tree fern material anywhere in the world, producing millions of pots, planters, and substrate blocks annually. The industry employed thousands of workers in rural communities. Its decline following environmental regulation caused economic disruption in some areas, leading to tension between conservation objectives and local livelihoods. Alternative materials including coco coir, expanded clay, and synthetic polymer substrates have largely replaced xaxim in Brazilian horticulture.

Frequently Asked Questions