92 TAKEDA—JAPANESE PRIMULAS. 
The fourth has been described by Petitmengin! from the 
Loochoo. This plant —— to be identical with Stimpsonia 
chamaedrioides, Wright.? 
HYBRIDIZATION. 
Hybridization is very common amongst Primulas. Even 
in the field, when two or more closely allied species grow together, 
hybridization often takes place, as in the Alps and elsewhere. 
In Japan, this has hardly been known, since different species 
grow in different localities, but not mixed together. As far as 
the breed is concerned all the species are pure. All the garden 
forms of P. Sieboldii have been produced only by natural crossing 
between different forms of the same species which is rather 
plastic in nature. 
This species has been a favourite of plant growers over two 
centuries. 
ANALYTICAL KEY TO SPECIES AND VARIETIES. 
With the purpose of facilitating identification of the Japanese 
Primulas, I add a key to the species :— 
Clavis Specierum Varietatumque Primularum Japonicarum. 
1. Folia plus minusve lobata, distincte petiolata ; : 2. 
Folia basi in petiolum attenuata, nec lobata ; : 6. 
2. Folia oblonga vel ovato-oblonga, lobata, 
obis numerosis. Calyx infundibuli- 
formis, laciniis acutis patentibus, post 
anthesin accrescens. Rhizoma repens . P. Sieboldit. 
Folia ambitu rotundata, reniformia, vel late 
ovata. Rhizoma erectum, breve : ; : 3. 
3. Plant busta, ultra 15cm.alta. Calyx 
ultra 1 medium fissus, lobis acuminatis . ‘ ‘ 4. 
Planta tenuis. Calyx ad medium fissus.. . . 5- 
4. Planta plerumque ainsi glabrescens 
vel villosula. Folia reniformi-orbicu- 
lata, profunde cordata, palmate 5-7-9- 
lobata, lobis oe ee ee acute 
denticulatis. Calyx ange vel leviter 
hirtellus : -  P.jesoana. 
1 Petitmengin, Sur — — monocarpique de Japon., in Bull. Herb. 
Boiss. sér. 2, viii (1908), P 
2 Apud A. Gray, Bot. — (1859), p. 401, in Adnot, 
