Endemic plants of Mt. Apoi
Endemic species

Quasi-endemic species

Endemic subspecies
Quasi-endemic subspecies
Endemic variant species

Quasi-endemic variant species

Endemic varieties

Quasi-endemic varieties

Mysterious vegetation of Mt. Apoi

Cirsium apoiense
Hypochoeris crepidioides
Betula apoiensis
Hyericum samaniense
Callianthemum miyabeanum
Eriocaulon perplexum
Primula hidakana
Rhamnus isidae
Thalictrum integrilobum
Crepis gymnopus
Carex apoiensis
Saussurea riederi ssp. kudoana
Angelica acutiloba ssp. lineariloba
Erigeron thunbergii var. angustifolius
Primula modesta var. samanimontana
Tilingia ajanensis var. angustissima
Aruncus dioicus var. subrotundtus
Arenaria katoana var. lanceolata
Silene repens var. apoiensis
Potentilla matsumurae var. apoiensis
Thalictrum foltidum var. apoiense
Lespedeza bicolor var. nana
Aconitum yuparense var. apoiense
Allium schoenoprasum var. yezomonticola
Bupleurum nipponicum var. yesoense
Viola brevistipulata var. hidakana
Pedicularis yezoensis var. pubescens
Tofieldia coccinea var. kondoi
Veronica schmidtiana var. yezoalpina f. exigua
Anaphalis alpicola f. robusta
Hylotelephium cauticolum f. montanum
Peucedanum multivittatum f. linearilobum

Apoiazami
Ezokozorina
Apoikanba
Samaniotogiri
HidakasoEzoinunohige
Hidakaiwazakura
Miyamahanmodoki
Samanikaramatsu
Ezotakanenigana
Apoitanukiran
Hidakatohiren
Hosobatoki
Apoiazumagiku
Samaniyukiwari
Himeshiraneninjin
Apoiyamabukishoma
Apoitsumekusa
Apoimantema
Apoikinbai
Apoikaramatsu
Chaboyamahagi
Hidakatorikabuto
Himeezonegi
Ezosaiko
Ezokisumire
Birodoezoshiogama
Apoizekisho
Apoikuwagata
Apoihahako
Apoimisebaya
Ezonohakusanbofu

Abnormal vertical distribution of Erman’s birch forest at the summit

Normal alpine vegetation

Mountain vegetation in Hokkaido usually changes as altitude increases:
broad leaf forest zone → coniferous forest zone → Erman’s birch zone →dwarf stone pine zone. On Mt. Apoi, however, there are Erman’s birch
forests in the area from the ninth stage to the summit, despite the area
being at a higher altitude than the dwarf stone pine forest zone. Weakerwinds are considered to be one reason, but the underbrush includes
plants that usually grow at the foot of mountains, such as lilies of thevalley and ezoosakuraso (Primula jesoana var. pubescens), which only
adds to the mystery.

Dwarf stone pine zone
Erman’s birch zone
Coniferous forest
zone
Broad leaf forest zone

Vegetation along
the mountain trail on Mt Apoi

Erman’s birch forest immediately below the summit

Erman’s birch zone

Dwarf stone pines that grow from an altitude of approximately 300 m

Ninth stage

Dwarf stone pinezone
Erman’s birch zone
Seventh stage
Glehn's spruce
Kitagoyo (P. parvifloravar. pentaphylla) forest

Dwarf stone pine zones or alpine zones usually appear at altitudes of at least 2,500 m in the central Honshu
region and 1,000 m or more in Hokkaido. On Mt. Apoi, however, alpine plants can be seen from the fifth stage(approx. 350 m), and dwarf stone pine communities can be found at an altitude of 300 m depending on the area.
Climatic conditions can be considered, but what is more predominant is that the special soil conditions ofperidotite are considered to hinder normal vegetation and bring about the same effects as those found in colder
climates at the same altitude.

Fifth stage

Mixed coniferous/broad leaf forest

Alpine plant flowering seasons
Mt. Daisetsu

Can Alpine flowers here be enjoyed from the earliest and for the longest periods of anywhere in Japan?

Mar.

June

Sept.

Dec.

Feb.

Dec.

Feb.

FloweringseasonThe blooming period of alpine plants depends on the when the snow melts. On Mt. Apoi, the winter snowfall is far
less than normal mountains with alpine vegetation. Most of the snow disappears by mid-April, and hidakaso(Callianthemum miyabeanum) and samaniyukiwari (Primula modesta var. samanimontana) begin to bloom inearly May. As the mountain is relatively low, the first snow of the season comes late, resulting in the unusuallylong flower season of nearly half a year to October, when kohamagiku (Chrysanthemum yezoense Maek.) are inbloom.

Mt. Apoi
Mar.

June

Sept.

Floweringseason

Hidakaso

Ezokozorina

Apoikanba

Samaniyukiwari

Apoiazumagiku

Apoitachitsuobosumire

Ezokisumire

C a l l i a n t h e m u m m iyabeanum

Hy poc hoe ris c re pidioide sB e tu la a p o ie n s isP r im u la m o d e s ta v a r . s a m a n im o n ta n a

E r ig e r o n t h u n b e r g i i v a r . a n g u s t i f o l i u s

Vi o l a s a c h a l i n e n s i s v a r . a l p i n a

Vi o l a b r e v i s t i p u l a t a v a r . h i d a k a n a

Hidakaiwazakura

Apoikaramatsu

Apoitsumekusa

Apoikuwagata

Apoizekisho

Apoihahako

Apoiyamabukishoma

P ri m u l a h idakana

Thalic trum foltidum v ar. apoie nse

Are n a r ia k a to a n a v a r . la n c e o la ta

Veronica schmidtiana var. yezoalpina f. exigua

To fie l d i a c o c c i n e a v a r . k o n d o i

An a p h a l i s a l p i c o l a f . r o b u s t aAr u n c u s d i o i c u s v a r . s u b r o t u n d u s

Himeezonegi

Apoikinbai

Ezorurimurasaki

Apoimantema

Chaboyamahagi

Samaniotogiri

Samanikaramatsu

Allium schoenoprasum var. yezomonticola

Pote ntilla matsumurae v ar. apoie nsis

Eritr ic h iu m n ip o n ic u m v a r . y e z o e n s e

S ile n e r e p e n s v a r . a p o ie n s is

Le s pe d e z a b i c o l o r v a r . n a n a

Hyericum samaniense

Thalictrum integrilobum

Himechamadaraseseri Pyrgus malvae

Nationally-designated natural monument (designated in 1975)

Apoimaimai Paraegista apoiensis

Himechamadaraseseri (Hesperiidae family) is a small butterfly with a wingspan of2.5 cm. This brownish-red butterfly with white spots is distributed mainly innorthern areas including Russia and Mongolia, and in Japan it is found only at thealpine zone of Mt. Apoi. The butterfly was discovered on Mt. Apoi in 1973 by
students of the Hokkaido University Insect Research Group, and its biology wasclarified by the group the following year. The butterflies in their larval stage
consume shrubby cinquefoils, an alpine plant, and adult butterflies are seen only
during a period of approximately one month from early May to early June.
Himechamadaraseseri were widely distributed in the Ice Age, but are considered
to have remained here on Mt. Apoi by chance as global warming spread.

Apoimaimai is a snail endemic to the Apoi mountain mass and its surroundings,
as well as the area along the Horoman River (registered as a new species in1970). This snail is a species related to takahidemaimai of the Himemaimai
genus that inhabits Hokkaido, and lives in cracks among piles of peridotite
rocks. The shell of an adult snail measures approximately 1 cm and ischaracterized by the stiff, thin hairs on its surface.

Japanese pika Ochotona hyperborea

Other animals on Mt. Apoi

The Japanese pika is a kind of hare well known as a relict species from the Ice
Age. The brown animal, which measures approximately 15 cm in length, hasrounded ears and gives off a high-pitched warning call. It inhabits central
Hokkaido and the alpine zone of the Hidaka Mountains. The southern part ofHidaka is almost the southernmost limit of pika’s habitat in the world, and theanimal is distributed there at very low altitudes. It is found not only in the upper
part of the Apoi mountain mass but also in a 50-m-high conglomerate area along
the Horoman River.

Black woodpecker
Dryocopus martius

Hokkaido sika deer
Cervus nippon

Hokkaido squirrel

Sciurus vulgaris orientis

Chipmunk

Tamias sibiricus

Japanese crayfish

Cambaroides japonicus

Peridotite
A message from the mantle

Mantle appearing on the surface of the earth

The home of magma [Horoman peridotite]

Mt. Apoi is formed of a rare rock known as peridotite. The rock, the specific gravity (3.3g/cm 3) of which is the heaviest on earth, is high in magnesium and iron, and isclassified as ultramafic (ultrabasic) rock with low silica content, in which plants tend todevelop special properties. One of major minerals of peridotite is olivine, and the word
olivine is derived from its color, which is similar to that of olives. When a slice of
peridotite is observed under a polarizing microscope, it looks like beautiful stained
glass (see the front cover). The picture on the front page looks like a garden of colorfulflowers spreading under the alpine plant community. A large crystal of olivine is known
as peridot, and is used as a gemstone (the birthstone of August).

The earth consists of the core in the center, a thinsurface layer known as the crust, and the substance
between the core and the crust that is known as
mantle, which accounts for approximately 80 % of theearth’s volume. In fact, peridotite is a rock that forms
the upper part of the mantle, and only exists several 10km deep under the ground. It is rock that should not beon the surface. Its exposure on the surface is related
to the formation of the Hidaka Mountains. That is,when the plate of the east collided with the plate to thewest, part of the mantle under the colliding plates was
pushed up and appeared on the ground surface.

It is known that the magma (molten rock) spewed out
by a volcano, oozes from the upper mantle, orperidotite. The Horoman peridotite complex, whichforms Mt. Apoi, consists of various types ofperidotite, from parts containing much magmacomponents to parts without magma. In addition, as
the freshness of the peridotite exposed on thesurface is so rare, the area attracts worldwide
attention in the field of geosciences, as a precious
place where incidences occurring in the mantle canbe observed from the ground.

The earth’ s internal structure

Plate collision

Structure beneath volcanoes

Crust
Crust

MantleMantleMantleMagma chamber

MantleCore
Magma formation
Peridotite

Peridot