Paper mulberry names
The main trees used for making paper in eastern Asia a southern species of Broussonetia and a hybrid between this and a northern wild species.
The naming of these trees has long been a source of confusion. A recent paper has reviewed the taxonomy:
Chung, K., Kuo, W., Hsu, Y. et al. (2017)
Molecular recircumscription of Broussonetia (Moraceae) and the identity and taxonomic status of B. kaempferi var. australis . Botanical Studies 58, e12 pp
In this paper, three species and a hybrid are recognised in the genus Broussonetia :
(1) B. kaempferi , (2) B. monoica , (3) B. papyrifera, (4) hybrid ( B. × kazinoki )
The Japanese vernacular names are noted as:
B. papyrifera = kazinoki
B. x kazinoki = kôzo (a cultivated hybrid in Japan and Korea; Korean vern. name = daknamu ) (= B. papyrifera x B. monoica )
B. monoica (hime-kôzo) (previously known as B. kazinoki )
B. kaempferi = tsuru-kôzo (a clambering/scandent vine.
Historically, vernacular names do not always and everywhere correspond to the botanical taxa recognised now. This is usual when we compare the vernacular names and scientific names of plants.
As a result, there is naturally some confusion when comparing historical literature written in a vernacular language, and modern botanical literature.
From a botanical historical perspective some key questions are where and when did the useful hybrids appear , and are the cultivated hybrids fertile, and are their offspring fertile?
It is highly likely that hybrids (i.e. kôzo) appeared more than once in the vicinity of cultivated populations of B. papyrifera , which is able to breed quite far north, despite its natural distribution in subtropical region of Southeast Asia and southern China. The hybrids may be vegetative and/or breeding populations located in the vicinity of past and present paper-making areas.