The author collected about 3, 500 samples of soils, cereals and many kinds of agricultural and aquatic products from many districts in Japan, and isolated 47 different strains of Aspergilli, which were characterized giving violet-black colonies, and carried out morphological and taxonomical studies on them together with 2 strains of Asp. japonicus SAITO and I strain of Asp, violaceo-fuscus GASPERINI NRRL 360.
One new species, Asp. acideatus (6 strains), two new varieties, Asp. japonicus var. viridiflavus (5 strains) and Asp. japonicus var. atrofuscus (1 strain), were isolated among them along with 35 strains of Asp. japonicus.
According to THOM and RAPER⁽¹⁾, Asp. japonicus together with Asp. luchuensis and Asp. violacca-fuscus were classified into the group of Asp. nigcr or the black Aspergilli, which were divided into two main subgroups by the arrangements of sterigmata, single or double series. According to INUI'S original descriptions⁽²⁾, Asp. luchucnsis produces heads with single sterig-mata exclusively.
K. SAKAGUCHI and the present author⁽³⁾ have, however; pointed out that 3 strains of Asp. luchuensis in the collection of Institute for Fermentation (in Osaka) and Department of Agricultural Chemistry, Univ. of Tokyo, are all provided with double sterigmata predominantly and single or mixed sterigmata partly or very rarely. Also Asp. violaceo-fuscus occasionally has double sterigmata as observed on NRRL 360 which the author received from Dr. K. B. RAPER in Oct. 1948. All the strains of Asp. japonicus and 47 strains in this experiment had, however, sterigmata in one series.
As it was shown in the electron micrographs (Fig: 1 to 4), the surfaces of the conidial wall of Asp. japonicus and these 47 strains were provided with densely aculeate processes, while those of Asp. luclzuensis and Asp. violacea-fuscus were rough and somewhat roughened.
Colonies of Asp. japonicus and these 47 strains were characterized by their violet-black heads, but those of Asp. luchuensis are brownish olive and of Asp. violaceo-fuscus NRRL 360 are light purple drab.
It is, therefore, conspicuous characteristics of Asp. jcponicus and these 47 strains that they produce exclusively violet-black conidial heads with single sterigmata and conidia which possess aculeate processes over the surface.
From the points mentioned above it seems to be unsuitable to sum up Asp. japonicus and these 47 strains in Asp. luchuensis series together with Asp. luchuensis and Asp. violaceo-fuscus, and it is not appropriate to put these “violet black Aspergilli” in Asp. niger group with Asp. carbonarius series and Asp. niger series. This is why the author has proposed here to classify them in the new “Asp. japonicus group” The above relations are shown in the following Key.
A Key for the classification of the violet black Aspergilli
I. Sterigmata in two series.
A. Conidia more than 5μ in diameter…………………………………A. carbonarius group.
B. Conidia mostly less than 5μ in diameter.
1. Conidial wall distinctly echinulate when mature………A. Niger group.
2. Conidial wall smooth, rough or rarely echinulate………Kuro-Koji mold group.
II. Sterigmata in one series, conidial walls densely aculeate………A. japonicus group.
A. Conidia strongly elliptical 4.0_??_6.5 ×2.8_??_3.2μ, vesicle 50_??_80μ, conidiophores long 3_??_4mm……………A. acuteatus IIZUKA sp. nov…(6 strains)