(Petasites japonicus
  subsp. giganteus )

Fuki-no-to (head of giant butterbur) indicates a part of the flower Akita-buki (Petasites japonicus subsp. giganteus ). After the bloom falls, leaves grow from underground stems, or butterburs.


(Anemone pseudoaltaica )

Growing in small colonies all around Oirase, this Species is representative of early spring and is called “Spring ephemeral.”


(Corydalis fukuharae )

Light blue to light purple flowers bloom on the forest floor in spring. They are often mixed in with a pure white variety of the flower, Shiro-otome-engosaku (Corydalis fukuharae f. albescens).


Soft windflower
(Anemone flaccida )

This flower creates a flower garden on a forest floor every May. This is one sign of spring that can be enjoyed for a relatively long time.


Wood lily (Indian tulip)
(Trillium smallii )

This lily has three leaves, three calyxes, and three petals. Although it contains toxic components, the root stock is used as an herbal medicine called longevity grass root.


(Viola kusanoana )

Flowers are light purple with a strong reddish tint and spurs are white in color. Leaves are heart-shaped, and the underground stems grow in colonies. Flowers rise to bloom.

(Tiarella polyphylla )

The shape gives the impression of a sparse brush, making the white sepals and filiform petals stand out. Its Japanese name references its possible use as a “medicine for asthma.” It is common to see in Oirase.

(Asperula odorata )

Features wheel-shaped leaves and produces small flowers in early summer that are delicately beautiful, like sugar confections. It also contains the perfume component “coumarin.”


(Mimulus sessilifolius )

Near the wet sandbar and influx of the stream you can see a vivid yellow background of tubular flowers with red spots sprinkled over them.


(Thalictrum filamentosum
  var. tenerum )

White, small flowers like sparklers resemble the leaves of the Japanese larch. After pollination, stamens fall and pistils turn crimson-magenta in color.

(Monotropastrum humile )

This used to be called saprophytic plant, which is well known as one of the flowers produced by non-photosynthetic plants. It obtains nutrition by mycorrhiza.

(Rodgersia podophylla )

Large-sized leaves resemble “an arrow wheel” (decorative windmill accompanied by carp streamers). Numerous small, star-shaped flowers gather to make , or spike.


(Scutellaria pekinensis
  var. ussuriensis )

The Japanese name is said to derive from Tatsunami (Standing Waves) painted by Hokusai, which was supposed to represent a blooming flower facing sideways.


(Cremastra appendiculate )

This flower is named for its shape resembling a saihai, a baton used by generals on the battlefield in ancient Japan. This plant co-exists with a mycorrhiza of Psathyrellaceae.

(Laportea cuspidate )

This plant has thorns on its stem and leaves, so please be careful not to touch it to avoid a painful accident. They are commonly called Aiko, its Sansai (edible wild plant) name.

(Filipendula kamtschatica )

A large herb resembling Japanese spirea (Spiraea Japonica), it clusters on trees in Oirase, and becomes conspicuous when flowering. The large leaf reminds one of an ogre’s palm.


(Angelica edulis )

Produces many small, white flowers in early summer that attract scores of hungry insects. The stems taste sweet and are used as edible wild plants.


(Gastrodia elata )

A variety of non-photosynthetic, fungus heterotrophic orchids which obtain nutrients by living on honey fungus. It has no leaves and stands upright only on the strength of the stem.

(Geum aleppicum )  

The Japanese name Daikon (white radish) derives from its radical leaves resembling a white radish. After the yellow flowers fall, seeds with hooks cling to animals and clothes of people.

(Aruncus dioicus
  var. kamtschaticus )

The leaves resemble those of the Japanese rose. A stamen pops out from the tip of a male flower. The female flower is characterized by a three-forked-stamen.


Water crowfoot
(Ranunculus nipponicus
  var. submersus )

This perennial plant of the family Ranunculaceae wavers in shallow, clear, cold flowing water. It is called Baikamo (plum flower seaweed) in Japanese for its water-blooming plum-like blossoms in summer.


Giant lily
(Cardiocrinum cordatum
  var. glehnii )

Several big flowers in the shape of trumpets growing on each stalk bloom in summer. The fruits are suggestive of green peppers. It is interesting to see the way it releases ripe seeds.

(Astilbe thunbergii
  var. congesta )

The Japanese name Tori-ashi derives from the appearance of its young leaves, which remind one of a bird drawing in its legs. It has conical spikes with a collection of white, small flowers in summer.

(Adenophora remotiflora )

Almost conical, bell-shaped flowers are light bluish-purple in color. The autumnal, generally slender flower gives a pretty impression. It is fond of watery environments.


(Desmodium podocarpum subsp.
oxyphyllum var. mandshuricum )

A variety of beggar-lice, the leaves are concentrated from the center to the bottom of the stems. By looking with a magnifier, you can see the beauty of this small, crimson-magenta flower shaped like a butterfly.


(Lilium medeoloides )

This lily makes one to several warping, reddish-orange flowers that bloom in early summer. Leaves are characterized by a thin, whorl shape resembling a wheel.

Yellow Balsam
(Impatiens noli-tangere )

A characteristic flower with a unique appearance as its name “yellow fishing boat” shows, it blooms from summer to early autumn. They produce many cleistogamous flowers and the seeds pop off when touched.

(Impatiens textori )

Hanging down from the tip of a thin peduncle is a purple and crimson flower which looks like a suspended sailing boat. The tip of the cylindrical flower is shaped like a coiled horn.


(Tricyrtis affinis )

Named after spots on the petals resembling spots on the breasts of Hototogisu (lesser cuckoo). Many can be seen in the upper stream in Oirase.


(Persicaria filiformis )

An herbaceous plant belonging to the genus Polygonum of the family Polygonaceae, it is named after the Japanese ceremonial paper cord (Mizuhiki), since its red and white inflorescence resembles this art form. It is commonly known as autumnal wild grass.

(Adenocaulon himalaicum )

The leaves resemble those of giant butterburs. Its flowers are seemingly simple, but on closer look are actually collections of white, decent flowers. Sticky seeds remain after the flower blooms out.

(Parasenecio farfarifolius
  var. bulbifer )

Sparsely located flower heads contain small flowers in fall. The corolla is yellow. This plant is characterized by spherical propagules beside the leaves.


(Goodyera foliosa var. laevis )

This evergreen perennial grows in colonies. From summer to autumn, it produces pinkish purple flowers. The Japanese name derives from its color, which has been likened to the sky at dawn.


Monkshood (Aconite)
(Aconitum japonicum
 ssp. subcuneatum )

The color of dark purple, it is shaped like an Eboshi (headgear worn by court nobles in ancient Japan), painting the forest floor in autumn. Surprisingly, the flowers are not well known. A deadly poison runs through the entire plant. Young leaves resemble those of wind flowers.

(Cimicifuga simplex )

Its Japanese name, Sarashina, derives from soaking young leaves in water after boiling them, and is not a homophone referring to soba (noodles made from buckwheat flour). These plants are known in Chinese medicine for having antipyretic activity.

(Agrimonia pilosa )

Slender, spiky yellow flowers have five small petals each. It belongs to the rose family and is distinct from Mizuhiki (Polygonum filiforme), which belongs to the family Polygonaceae.


(Solidago virgaurea
  subsp. gigantea )

The autumn flowers of this plant grow along the river and beach from Hokkaido to the Tohoku Area. Features include yellow flower heads that bloom close to the tips of stems.


Indian pipe
(Monotropa uniflora )

Makes flowers resembling Ginryo-so (Monotropastrum humile) that bloom in autumn near the forest floor. It is completely white as it contains no chlorophyll, but turns black when dried.

Jack in the pulpit
(Arisaema serratum )

Features stems with patchy patterns Arisaema serratum resembling snakes. The peculiar flowers bloom in early summer and their red seeds, which seem strangely glossy in the autumn forest, are remarkably conspicuous.

(Saxifraga fortunei
  var. alpine )

Growing on mossy, wet rocks and boulders in streams, this autumnal flower is characterized by thick, round leaves and white petals in the shape of the Chinese character for “big.”


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