Lemmaphyllum microphyllum C.Presl

Bean Fern, Japanese Bean Fern, Green Penny Fern, Japanese Beard Fern, Little Leaf Fern

Easy careEpiphyteNon-toxic2–6 cm

A tiny creeping fern from the shaded forests and rock faces of East and South Asia, Lemmaphyllum microphyllum is unusual in having two completely different frond types on the same plant. The sterile fronds are small and round — barely the size of a thumbnail — while the fertile fronds that carry the spores are narrow and elongated, reaching up to 6–8 cm. In the wild it grows as an epiphyte on tree bark and as a lithophyte on mossy rock surfaces, drawing moisture from humid air rather than deep soil. It is slow-growing but long-lived and does exceptionally well in closed terrariums, creeping steadily across cork, wood, or stone.

Build a terrarium with this plant
Bean Fern image

Care

Light

Shade tolerant(preferred)Indirect light

Humidity

High (60–80%)(preferred)Very high (80%+)

Temperature

0°C20°C40°C
5°C – 35°C

Soil

Sphagnum mix(preferred)Well draining

Moisture

Moist(preferred)

Soil pH

6 – 7

Appearance

Growth habit

Creeping

Leaf shape

RoundOval

Leaf texture

LeatheryWaxy

Distribution

Propagation

Spore propagation is feasible but requires sterile in vitro conditions for reliable results; gametophyte development from spores and subsequent sporophyte production via mechanical fragmentation of gametophyte tissue has been documented in research. For home cultivation this is a specialist technique — collect ripe spores from fertile fronds (the narrow elongated ones) and sow on sterilised sphagnum or agar in a sealed humid container. Germination and development to sporophyte stage takes several months.

References

  1. 1

    POWO (Kew) — Lepisorus microphyllus (C.Presl) C.F.Zhao, R.Wei & X.C.Zhang ex C.S.Chang, H.Kim & K.S.Chang (accepted name per Chang et al. 2021; Lemmaphyllum microphyllum C.Presl is a homotypic synonym; family Polypodiaceae; native range: Assam, China South-Central, China Southeast, East Himalaya, Hainan, Japan, Korea, Nansei-shoto, Taiwan, Vietnam; rhizomatous epiphyte)

    https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:3285020-4
  2. 2

    POWO (Kew) — Lemmaphyllum microphyllum C.Presl (synonym entry; first published in Abh. Königl. Böhm. Ges. Wiss., ser. 5, 6: 263 (1851); accepted by Ebihara 2017 and Roskov et al. 2018; synonym of Lepisorus microphyllus per Chang et al. 2021)

    https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:17336500-1
  3. 3

    Macau Biodiversity — Lemmaphyllum microphyllum (family Polypodiaceae; common name: 伏石蕨 (Chinese), Green penny fern (English); epiphytic on rocks and trees in shady forests; height up to 6 cm; native to China, India, Japan, Korea, Vietnam)

    https://www.macaubiodiversity.org/lemmaphyllum-microphyllum/
  4. 4

    Flora of China / eFloras — Lemmaphyllum microphyllum (plants to 6 cm tall; rhizomes pale green, sparsely scaly; fronds dimorphic: sterile fronds subsessile or stipe 2–4 mm, lamina orbicular/ovate/obovate 1.6–2.5(–5) × 1.2–1.5 cm, rounded or cuneate base, entire margin; fertile fronds stipe 3–8 mm, lamina oblong or narrowly lanceolate 3.5–6(–8) × 2–4 cm; veins reticulate; sori linear between costa and margin)

    http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200004887
  5. 5

    Glass Box Tropicals — Lemmaphyllum microphyllum (common name: Japanese Beard Fern; native to Japan, Korea, China, India, Philippines, and Asiatic Islands; epiphytic fern; best grown mounted with NZ long-fiber sphagnum; medium to high moisture; slower-growing; great terrarium fern; rated level 3 difficulty; fertile fronds ~2" long × ¼" wide; sterile fronds under ½" diameter)

    https://glassboxtropicals.com/lemmaphyllum-microphyllum/
  6. 6

    Micro Exotics — Green Penny Fern Lemmaphyllum microphyllum (common name: Green Penny Fern; temperature 18–25 °C; high humidity; indirect light; tiny fronds 1–3 cm; creeping over wood/stone/moss; excellent for terrariums, vivariums, paludariums; beginner-friendly rated 2/5; native to East Asia — China, Japan, Korea, Taiwan)

    https://www.microexotics.co.uk/store/Green-Penny-Fern-Lemmaphyllum-microphyllum-p477327156
  7. 7

    Fancy Fronds Nursery — Bean Fern Lemmaphyllum microphyllum (common name: Bean Fern; bean-shaped undivided foliage with brown spores on reverse; compact epiphytic spreading fern; mature size 1–2" tall, slowly colonising; shade/part shade/part sun; lightly moist to moist; USDA zones 9–10 or houseplant; does well in terrariums; evergreen; origin: Tropics/Sub-Tropics of Asia)

    https://www.fancyfrondsnursery.com/ferns/bean-fern-lemmaphyllum-microphyllum
  8. 8

    Orchids for the People — Lemmaphyllum microphyllum (epiphytic; moderate indirect light; medium to high moisture; slow-growing; best mounted with sphagnum; can also grow as ground sprawler; USDA zones 9a–9b; rhizome makes it easy to prune)

    https://orchidpeople.com/pages/lemmaphyllum-microphyllum
  9. 9

    Greg App — Lemmaphyllum microphyllum care (USDA zones 7a–10b; not known to cause harm to humans or pets; optimal temperature 18–24 °C; high humidity essential; low light; 0.5 cups water per 9 days in 5" pot)

    https://greg.app/plant-care/lemmaphyllum-microphyllum
  10. 10

    Greg App — All About Lemmaphyllum microphyllum: Essential Facts (common name: Little Leaf Fern; mature height 6–12 inches; spread up to 24 inches; optimal temperature 18–24 °C; high humidity; low light; soil pH 6.0–7.0; propagation by division and cuttings in spring/early summer)

    https://greg.app/littleleaf-fern-overview/
  11. 11

    PictureThis — Japanese Beard Fern Lemmaphyllum microphyllum (family Polypodiaceae; height 5–6 cm; spread up to 40 cm; native to southern and eastern Asia, India to Japan; grows on tree surfaces and rocks in humid shady environments; temperature 20–38 °C; high humidity; full shade; propagation by rhizome division; not documented as toxic; moderate difficulty)

    https://www.picturethisai.com/wiki/Lemmaphyllum_microphyllum.html
  12. 12

    Araflora — Japanese Bean Fern Lemmaphyllum microphyllum (common name: Japanese bean fern; creeping growth habit; humidity 60–90% day, 70–90% night; temperature min 5 °C, max 35 °C; soil pH 6–7; semi sun; easy to care for; terrarium suitable; mature spread up to 40 cm)

    https://www.araflora.com/p4001/japanese_bean_fern_lemmaphyllum_microphyllum
  13. 13

    JC Raulston Arboretum (NC State) — Lemmaphyllum microphyllum (common name: green penny fern; family Polypodiaceae; rhizomatous/stoloniferous fern; evergreen perennial; hardy to zone 7b; shade; height ~1 inch; spreading habit)

    https://jcra.ncsu.edu/horticulture/our-plants/results-by-name-serial-number.php?serial=128585
  14. 14

    Violet Barn — Lemmaphyllum microphyllum terrarium plant (common name: Japanese bead fern / Japanese beard fern; thick green leaves from fuzzy brown rhizomes; odd round little leaves; excellent for closed terrariums; slow grower; high humidity required; easy when given terrarium conditions)

    https://www.violetbarn.com/terrarium-miniature-plants/for-terrariums-dish-gardens/lemmaphyllum-microphyllum.html
  15. 15

    In Search of Small Things — Lemmaphyllum microphyllum (epiphytic fern; sterile fronds ~0.5" diameter; fertile fronds ~2" long, very narrow; native to China, Korea, India, Japan, Philippines, and Asiatic Islands; affinity for tree-fern substrate; waxy/resilient leaves; slow-growing)

    https://insearchofsmallthings.com/2019/08/20/lemmaphyllum-microphyllum/
  16. 16

    Springer Nature / In Vitro Cellular & Developmental Biology — Plant (Lemmaphyllum microphyllum C. Presl; practical methodology for gametophyte proliferation and sporophyte production using mechanical fragmentation; confirms spore propagation viability for mass production)

    https://link.springer.com/article/10.1007/s11627-020-10055-2