Ferns from the Warm South, Growing at Their Northern Edge
Behind the main hall of Murō-ji, a stone path climbs through dark cedar woods toward the temple's inner sanctuary. Partway up, on the eastern side of the trail, a small shaded ravine called Mumyō-dani cuts into the slope. The damp, sunless ground here holds a colony of ferns that belong, by rights, to the warm coasts of Shikoku and Kyūshū far to the south. Their presence this far north is the reason the spot was protected nearly a century ago.
The Murō-san Warm-Temperate Fern Colony (Murōzan Danchisei Shida Gunraku) sits within the grounds of Murō-ji, a Shingon temple in the Murō district of Uda City, Nara Prefecture. It was designated a National Natural Monument on November 30, 1928, under the slightly older spelling Murōzan Danchisei Shida Gunraku written with the classical character for fern. The designation recognized the ravine as one of the northern points where several heat-loving fern species were then known to grow in the wild.
Murō-ji itself is widely known as Nyonin Kōya, the "Women's Kōya." When the great monastic center of Mount Kōya barred women for centuries, Murō-ji welcomed them, and the nickname has stuck. The temple's wooded mountain has been guarded as sacred ground for well over a thousand years, which is part of why such a delicate plant community has survived here at all.
Why a Patch of Ferns Was Worth Protecting
The species that drew attention are warm-temperate ferns. Iyokujaku (Diplazium okudairae), Iwayashida (Diplaziopsis cavaleriana), Ōba-no-hachijōshida (Pteris excelsa), and Kiyosumi-himewarabi (Ctenitis maximowicziana) all favor the milder, more humid climate found from Shikoku and Kyūshū southward. In the early Shōwa period, botanists regarded the Murō ravine as one of the northern boundaries of their natural distribution, which made the site valuable for the study of how plants spread and where they stop.
The field survey that led to protection was carried out by Miyoshi Manabu, one of the figures who laid the groundwork for botany in modern Japan. He was guided to the ravine by Okamoto Yūji, a member of the Nara prefectural committee for historic sites and natural monuments, who had already combed the slopes of Murō-san and noted exactly which warm-climate ferns were growing there. In his official report of 1929, Miyoshi recommended that the fern community of Mumyō-dani be designated, writing that the distribution of this group of ferns at Murō was remarkable.
The protected area is small. Records from the Nara Prefectural Board of Education in 1962 give a registered figure of roughly 4 chō 6 tan, with a measured extent closer to 6 tan, while a 1995 reference work lists about 59 ares, a little under 6,000 square meters. The two designation criteria applied were the rule covering rocks and trees with a notable growth of attached plants, and the rule covering significant limits of plant distribution.
One honest caveat belongs here. The ferns once treated as reaching their absolute northern limit at Murō have since been confirmed growing further north. Yet in several individual prefectures these same species are now listed as locally extinct or endangered, so the colony has shifted in meaning from a frontier of distribution to a long-protected refuge.
The Ravine, the Mountain, and a Forest of 700 Plants
Murō-san rises to 636 meters directly behind the temple, its summit splitting into two peaks known as Yakeyama to the east and Nyoizan to the west. The whole mountain is wrapped in dense stands of Japanese cedar, hinoki cypress, and hemlock, and it forms part of the Murō volcanic group, a cluster of sharp peaks shaped by eruptions around fifteen million years ago. That steep, shaded, water-holding terrain is what lets southern ferns persist so far inland.
The fern colony is not the only botanical draw. A 1966 survey by the botanist Koshimizu Takuji counted roughly 710 plant species across about 156 families on the mountain, of which ferns alone accounted for 18 families and 113 species. Koshimizu described the approach to the temple as giving the impression of a great botanical garden. Two plants even carry the Murō name: Murō-mamushigusa (now usually called Kishida-mamushigusa, Arisaema kishidae) and Murō-tennanshō (Arisaema yamatense), both first gathered here in the early twentieth century and named by leading botanists of the day.
At the ravine you will find a stone marker recording the natural-monument status, set beside a small bridge on the path, together with a wooden signboard. The ferns themselves grow low among the undergrowth on the shaded slope, so this is a place to slow down and look closely rather than expect a dramatic view. Late spring and summer, when the fronds are fully out, reward visitors who pause to study the differences between one species and the next.
Reaching the Colony and What Lies Nearby
The colony is part of the Murō-ji visit, lying about 500 meters from the main hall along the climb toward the inner sanctuary. To reach it you enter the temple in the normal way. From Murōguchi-Ōno Station on the Kintetsu Osaka Line, a Nara Kotsu bus bound for Murō-ji takes about 14 minutes to the last stop, followed by a five-minute walk to the temple gate. Drivers usually leave the Meihan National Highway at the Hari interchange, roughly 25 minutes away.
Once inside, the route passes some of Murō-ji's celebrated buildings, including its small five-storied pagoda and the Golden Hall, both National Treasures. The temple is also famous for rhododendron in mid-spring and for autumn foliage, so the fern ravine is best treated as one stop on a fuller visit. Because the colony sits on a working pilgrimage path within a Buddhist temple, the usual courtesies apply: stay on the path, and do not collect or disturb the plants.
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Q&A
- Do I need to pay to see the fern colony?
- The colony stands inside the precincts of Murō-ji, so you pay the temple's standard admission to enter. There is no separate charge for the ferns themselves.
- When is the best time to visit?
- Late spring through summer is ideal, when the fronds are fully developed. The same season also brings Murō-ji's rhododendron, while autumn adds colored leaves along the path.
- What exactly will I see?
- A shaded ravine where low-growing ferns cover the slope beneath cedar woods, marked by a stone monument and a signboard near a small bridge. It is a quiet, close-up sight rather than a sweeping panorama.
- Why are these ferns considered special?
- They are warm-climate species more typical of Shikoku and Kyūshū. When the site was designated in 1928, it marked one of the northern edges of their known wild range, which made it useful for studying plant distribution.
- How is it linked to Murō-ji's history?
- The temple, known as the Women's Kōya, has protected its mountain as sacred ground for centuries. That long stewardship helped this fragile plant community survive in one place.
Basic Information
| Name | Murō-san Warm-Temperate Fern Colony (Murōzan Danchisei Shida Gunraku) |
|---|---|
| Location | 78 Murō, Uda City, Nara Prefecture (within the grounds of Murō-ji) |
| Designation | National Natural Monument |
| Date of Designation | November 30, 1928 (Shōwa 3) |
| Designation Criteria | Rocks or trees with notable attached plant growth; significant limits of plant distribution |
| Protected Area | Approximately 59 ares (about 6,000 m²) |
| Key Species | Iyokujaku, Iwayashida, Ōba-no-hachijōshida, Kiyosumi-himewarabi and other warm-temperate ferns |
| Access | About 5 min on foot from the Murō-ji bus stop (Nara Kotsu bus, approx. 14 min from Murōguchi-Ōno Station, Kintetsu Osaka Line); the colony is about 500 m beyond the main hall |
| Viewing | Open within Murō-ji's visiting hours (8:30–17:00, Apr 1–Nov 30; 9:00–16:00, Dec 1–Mar 31); temple admission required |
References
- National Designated Cultural Properties Database (Agency for Cultural Affairs) — Murō-san Warm-Temperate Fern Colony
- https://kunishitei.bunka.go.jp/bsys/maindetails/401/1966
- Uda City Official Website — Murō-san Warm-Temperate Fern Colony (Nationally Designated)
- https://www.city.uda.lg.jp/map/19065.html
- Nyonin Kōya Murō-ji — Visiting and Access Guide
- https://www.murouji.or.jp/guide/
- Nyonin Kōya Murō-ji — Official Website
- https://www.murouji.or.jp
Last verified: 2026.05.28