Introduction & Discovery

Davallia tyermannii is the silver-scaled representative of the footed-fern family, a species distinguished among cultivated Davallia primarily by the striking pure white to very pale silvery scale covering of its creeping rhizomes that gives the plant its common name White Rabbit's Foot Fern. Native to the humid subtropical and tropical forests of southern China, northern Indochina, Taiwan, and the northern Philippines, the species grows as a mid-canopy to lower-canopy epiphyte on the mossy branches of broadleaved trees, with frequent lithophytic populations on shaded limestone outcrops in the karst landscapes that characterise much of its core range. The specific epithet tyermannii commemorates James Tyerman, a nineteenth-century English gardener and Chief Gardener at the Liverpool Botanic Garden whose contributions to plant introduction and horticultural display were recognised by several plant dedications during the mid-Victorian period. The species entered European and American cultivation in the second half of the nineteenth century, during the peak of the Victorian pteridomania fern craze, and has been continuously available through specialist fern nurseries since. A note of confusion persists in the horticultural literature between this species and Humata tyermannii, the familiar Bear's Paw Fern houseplant of Pacific origin; the two share the Tyerman commemorative epithet despite belonging to separate genera within Davalliaceae and showing distinct morphological and ecological characteristics. Reliable identification depends on scale colour, rhizome diameter, and frond dissection: Davallia tyermannii has slender rhizomes 6 to 10 millimetres in diameter covered in pure white to pale silvery scales, tripinnate-quadripinnate fronds 25 to 45 centimetres long with delicate dissection, and a continental Southeast Asian origin. Humata tyermannii (treated separately in this encyclopaedia) has thicker, darker-scaled rhizomes, simpler bipinnate-tripinnate fronds, a more compact stature, and a Pacific Fijian origin. In contemporary cultivation D. tyermannii occupies a specialist niche in the collections of Davallia enthusiasts, tropical fern keepers, and public botanical gardens with comprehensive Davalliaceae holdings, where its striking pale-silvery rhizomes against a green mount or basket create a visually distinctive display that no other species in the genus can quite replicate. The plant is a good addition to a mixed Davallia collection and provides a rewarding cultivation subject for growers who have mastered the basic principles of epiphytic fern care.

Discovery & Naming

Davallia tyermannii was formally described in the second half of the nineteenth century as British and European botanical exploration of southern China, Hong Kong, and Indochina intensified in the decades following the Opium Wars and the expansion of European trade networks across the region. The species was named in honour of James Tyerman, a nineteenth-century English gardener and Chief Gardener at the Liverpool Botanic Garden during the mid-Victorian period, whose horticultural contributions were recognised by several plant dedications. Type material is generally attributed to southern Chinese specimens accumulated at Kew through colonial plant-collecting networks. The genus Davallia had been established by James Edward Smith in 1793 based on the Canary Islands D. canariensis, with the generic name honouring Edmund Davall, the Swiss-English botanist; D. tyermannii was accommodated within the genus as an Asian addition to the accumulating roster of species. Nineteenth-century pteridologists including William Jackson Hooker, John Gilbert Baker, and Karel Bořivoj Presl contributed to the clarification of the species and its place within davallioid taxonomy, and the species featured in Hooker's Species Filicum and the Synopsis Filicum. Twentieth-century monographic work by Holttum, Copeland, and Pichi Sermolli refined the circumscription within Davalliaceae. A persistent source of confusion in the literature is the shared Tyerman commemorative epithet with Humata tyermannii, a separate species of Fijian Pacific origin described around the same period; the two are genuinely distinct at the genus level despite the shared honorific. Molecular phylogenetic work in the twenty-first century has supported the placement of D. tyermannii within a well-defined continental Southeast Asian clade of Davallia.

Native Range & Distribution Map

Distribution map showing the native range of Davallia tyermannii.

Biology & Frond Morphology

Davallia tyermannii belongs to the genus Davallia in the family Davalliaceae, producing evergreen, monomorphic, tripinnate to quadripinnate fronds of moderate size and fine texture, typically 25 to 45 centimetres long and 12 to 22 centimetres wide. blades are broadly ovate to deltate in outline, tapering gradually from the broadest basal zone to a gradually acuminate apex. stipes are slender, 10 to 20 centimetres long, pale straw to pale chestnut. the lamina is thin to medium in texture, medium to bright green, and more delicately dissected than d. denticulata or d. solida but slightly coarser than d. trichomanoides. pinnule margins are typically entire to finely denticulate. ultimate segments are oblong-cuneate, 3 to 7 millimetres long and 1 to 2 millimetres wide, each with a single forking vein. the distinguishing feature of this species is not the fronds themselves but the densely whitish-furred rhizomes that give the plant its common name white rabbit's foot fern. 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 Davallia tyermannii 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 Davallia tyermannii 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

Several common errors undermine cultivation of Davallia tyermannii. Planting in standard potting soil retains moisture excessively around the rhizome and causes rot; only coarse bark-based epiphytic mixes are appropriate. Burying the rhizome at planting or repotting suffocates tissue and damages the delicate white scale covering; the rhizome must lie on the substrate surface with its upper surface fully exposed. Overwatering reflecting general assumptions about fern moisture requirements causes chronic rhizome decline; the species prefers a distinct wet-dry rhythm with noticeable drying between irrigations. Handling the rhizomes excessively during repotting, propagation, or cleaning damages the pure white scale covering which is the species' principal ornamental feature and cannot be restored once lost on affected rhizome sections. Irrigating with hard or calcium-rich water leaves mineral deposits on the pale scales that discolour the ornamental surface; use rainwater or reverse-osmosis water wherever practical. Positioning in stagnant high-humidity environments such as sealed terrariums or bathrooms with very still air encourages algal growth on the white scales, degrading the ornamental appearance; maintain modest air movement. Cold exposure below 12 degrees Celsius damages rhizome growing tips and causes frond yellowing. Applying horticultural oil directly on rhizome scales leaves residues that discolour the ornamental surface; treat pest issues with spot alcohol application rather than foliar oil sprays on rhizomes.

Seasonal Considerations

Spring (March to May in the Northern Hemisphere) is the principal growth period. Resume fortnightly feeding at quarter to half strength in mid-March, increase watering frequency as temperatures rise, and complete repotting, division, and rhizome cuttings in April and early May before full frond expansion. New croziers emerge abundantly from mid-April on established plants. Summer (June to August) is peak vegetative activity. Water every three to five days with attention to substrate drainage. Fortnightly feeding continues. Monitor for scale insects and mealybugs in rhizome scale crevices where they are particularly well camouflaged. Ensure humidity remains above 50 percent; air conditioning can drop indoor humidity sharply in hot weather. Autumn (September to November) brings progressive slowing. Reduce watering frequency toward every five to seven days, taper feeding through September and cease by month end. Remove any yellowing older fronds at the stipe base. Inspect rhizomes for scale insects that have accumulated during the summer. Gentle brushing with a soft dry brush removes dust from white scales. Winter (December to February) is minimal-demand rest. Water every seven to ten days, enough to maintain rhizome turgor without saturating the substrate. No feeding. Maintain temperatures above 14 degrees Celsius at all times. Mist foliage weekly in heated indoor rooms to counter dry air, but avoid direct wetting of rhizome scales which encourages algal growth. Brief cool rest at 12 to 15 degrees Celsius is acceptable and may stimulate spring flush.

Diseases & Pests

Common issues affecting Davallia tyermannii 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

Davallia tyermannii 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

Davallia tyermannii 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

Davallia tyermannii has not been formally assessed at the species level on the IUCN Red List and no CITES listing applies. Across its Southeast Asian native range the species is locally common in suitable habitat, with substantial populations documented from Taiwanese, southern Chinese, and northern Indochinese forests. Regional populations face variable pressure from habitat loss: lowland forest in southern China, Vietnam, and the Philippines has been extensively cleared for agriculture, plantation, and urbanisation over the past century, and epiphytic populations have declined correspondingly. Karst limestone habitats which support substantial lithophytic populations are often spared from conversion due to terrain constraints, and serve as important refugia for the species across parts of its range. Collection pressure from the wild for the horticultural trade is minimal because commercial propagation by rhizome division and tissue culture meets demand globally, and wild-collected stock has no commercial advantage over nursery material. Some traditional medicine use in parts of the range imposes local harvesting pressure but this is generally limited in scale. Conservation priorities for the species at the regional level centre on habitat protection in areas of remaining primary and well-managed secondary subtropical forest, retention of mature host trees in agroforestry landscapes, and protection of karst limestone habitats which support multiple endemic and regionally distinctive epiphytic fern species in addition to D. tyermannii.

Collector Notes

For Davallia collectors, D. tyermannii is an essential species representing the pure-white-scaled end of the scale-colour spectrum and providing striking visual contrast with the warmer-toned D. fejeensis, reddish-brown D. solida, and pale brown D. denticulata. The species is less frequently encountered in the horticultural trade than the mass-market D. fejeensis but is reliably available through specialist fern nurseries, plant society exchanges, and botanical garden sales in Asia, North America, and Europe. Wild-provenance material of documented origin is worth seeking as the species exhibits some regional variation across its range in rhizome diameter, scale density, and frond dissection; Taiwanese, southern Chinese, Vietnamese, and Philippine provenances may show subtle differences worthy of comparative cultivation. Care in identification is important because of the shared epithet with Humata tyermannii (Bear's Paw Fern), which is widely available and commonly mislabeled in retail settings; confirm identity from rhizome diameter, scale colour, and frond dissection rather than label alone. Notable cultivated specimens are held at the Singapore Botanic Gardens, the Royal Botanic Gardens Kew Princess of Wales Conservatory, the Taiwan Endemic Species Research Institute collections, and various botanical gardens in southern China and Vietnam. A complete Davallia collection at the genus level would include D. canariensis, D. mariesii, D. trichomanoides, D. fejeensis, D. solida, D. denticulata, and representative Humata species.

Ethnobotany & Cultural Significance

Davallia tyermannii has a limited and regionally concentrated ethnobotanical record, reflecting its distribution across parts of southern China, Taiwan, and northern Indochina where traditional medicine traditions have long utilised various Davalliaceae species. The rhizomes are occasionally incorporated in regional folk medicine formulations for bone-setting, kidney complaints, and minor wound treatment, overlapping in application with the better-documented D. mariesii (gu sui bu) of East Asian traditional medicine, though D. tyermannii is not a major ingredient of the classical Chinese pharmacopoeia and the overlap should be understood as local ethnobotanical use rather than formal traditional medicine practice. In some Taiwanese and Fujianese traditional practices the species has been used interchangeably with D. mariesii in bone-setting formulations, reflecting local availability rather than formal medicinal equivalence. Modern phytochemical investigation of the species is limited compared with D. mariesii, and specific bioactive compounds have not been extensively characterised. In horticultural and decorative contexts the species has been cultivated in European and American tropical glasshouses since the mid-nineteenth century Victorian pteridomania era, valued for the distinctive white-scaled rhizomes that set it apart from other Davallia available at the time. The species continues to hold a niche in contemporary specialist horticulture in Asia, Europe, and North America, with specialist fern nurseries maintaining stock and occasional offerings at plant shows and in enthusiast society exchanges. The commemorative epithet tyermannii honours James Tyerman, a nineteenth-century English gardener and Chief Gardener at the Liverpool Botanic Garden, whose horticultural contributions were recognised by several plant dedications during the mid-Victorian period.

Frequently Asked Questions