DISSECTED-LEAF SPECIES OF VIOLA IN EAST ASIA
The group of species with dissected leaves in eastern Asia
including Japan has many problems of taxonomy.
In general (in Japan) the recogized taxa are as outlined below. But this view is provisional and not the
only one.
Viola
chaerophylloides f. sieboldiana
Japan
Viola chaerophylloides f. chaerophylloides Japan(rare), Korea, China(Manshuria), Russia(Pirmorie)
Viola eizanensis Japan
Viola dactylloides China(Manshuria), Russia(Pirmorie)
Viola dissecta China, Russia(Pirmorie)
There are two types of this species. One with deeply
dissected leaves divided into linear lobes and another with comparatively wide
lobes. The former is f. sieboldiana and
the latter is f. chaerophylloides. The former has wider distribution (from
Russian Pirmorie, China, Korea and Japan) than the latter (Korea, China (Manshuria),
Japan (rare)).
In Japan almost all occurrences of V. chaerophylloides are f. sieboldiana. Only in a
limited area (Tsushima Island) we can see f. chaerophylloides. But there is some
debate whether the plants on Tsushima and those in the other countries are the same.
And botanists in both China and Russia ordinarily donft recognize taxa below
species level in V. chaerophylloides.
I have never seen this species on the continent except in a herbarium, so I donft have
enough knowledge to comment further, especially about f. chaerophylloides.
This species is endemic in Japan. Its habitat is shadier
and more moist than that of V. chaerophylloides.
Ordinarily these two species select different habitats to each other. V. chaerophylloides likes dry
meadow or sparse woods in Japan.
Viola eizanensis is more common than V. chaerophylloides in Japan.
These two species have almost no barriers to reproduction. If they
cross with each other, their F1 has almost complete ability to reproduce.
However these two species are recognizable as separate species because their
habitats are considerably different and because of their form in general.
However, in rare cases, colonies of F1 or intermediates between these two species are
found.
Viola dissecta
This species does not occur in Japan.
I have seen living plants only once and one individual in
Pirmorie, Russia. Although this
species is similar to V. eizanensis, there are some differences in the shape of the
leaves. The main point is the angle of the leaf base. In the case of V. dissecta, the petiole and base of leaf is vertical
and in the case of V. eizanensis it is less than vertical.
The habitat of V. dissecta I saw in Russia was dry meadow - where V. eizanensis
could never live.
Viola dactylloides
This species has several distinguishing points of identification compared with other dissected-leaf species. One of these is the leaf is divided into five parts completely; also, the lobes are not deeply dissected. This species does not occur in Japan. I have only seen a few individuals of this species, in Pirmorie Russia, and only once.
All rights reserved Masashi Igari 2001