Abstract
WEIR and HUBERT (31) have suggested that the teleutospores of Uredinopsis Pteridis DIET. et HOLW. seem to have the power of germinating as soon as they are ripe without hibernation, and the needles of Abies become infected during the late summer or fall, and the aecidia appear early in the next spring. According to the writer's investigations, however, the teleutospores. of Uredinopsis Pteridis on Pteridium aquilinum KUHN var. japonicum NAKAI collected in the vicinity of Sapporo were proved to germinate in spring after having overwintered and to infect Abies Mayriana MIYABE et KUDO, when the needles are still young. The peridermial stage developed in about a month after the inoculation. (Fig. 1.)
The aecidiospores thus obtained from the infection experiments were proved to infect the Japanese bracken, on which uredospores similar in characters to those found in the field were produced.
The peridermial stage of Uredinopsis. Pteridis in the Pacific States of North America, was identified by JACKSON with Peridermium pseudobalsameum ARTH. et KERN, which appears always on the second year needles of Abies grandis, nobilis and amabilis.
The writer could not help entertaining a grave doubt on the assertion of WEIR, HUBERT and JACKSON as to the life-cycle of Uredinopsis Pteridis in Western America. The repeated infection experiments performed by the writer have invariably shown that the aecidial stage of the fungus is formed on the young leaves of Abies Mayriana in late spring accompanied by spermagonia having a flattened conoidal to lense-like shape of the type of Peridermium balsameum PECK (Fig. 4, 5, 7), the characters common to other species of Uredinopsis. Moreover, according to HUNTER, the spermagonia of Uredinopsis Pteridis (Peridermium pseudobalsameum ARTH. et KERN) have hemispherical, vertically elongated shape as shown in Fig. 6.
The spermagonia and peridermia formed on Abies Mayriana by the inoculation of the sporidia of Uredinopsis Pteridis are fully described as follows:
O. Spermagonia amphigenous, mostly hypophyllous, on discolored areas, minute, numerous, punctate, irregularly and closely aggregated or scattered, (Fig. 3) usually isolated, at times confluent, honey-yellow at first, becoming later reddish brown, subcuticular, lenticular to subconoidal in shape, (Fig., 4 5, 7) 66-132μ broad, 37-66μ high; spermatophores obclavate, septate spermatia oblong or oblong-ovate, 1.6-2.8μ broad, 4.5-6.7μ long. (Fig. 8)
I. Peridermia amphigenous, mostly hypophyllous, arranged in two rows on pale yellowish areas, occupying a part or all of the leaf, cylindrical, (Fig. 2, 3) 1.0-7.5mm. high, 0.3-0.5mm. across; peridium colorless, rupturing at apex, cells slightly overlapping, rhombic to hexagonal, 11-22μ broad, 19-40μ long, inner wall coarsely verrucose, 3-7μ thick, outer thinner ca, 1μ, smooth. Aecidiospores globoid to ellipsoidal, 15-24μ broad, 18-30μ long, mostly 20×22μ; wall colorless, 1-2μ thick, rather densely verrucose except a side having almost smooth wall; contents colorless; germpores invisible.
O and I on the current year needles of Abies Mayriana MIYABE et KUDO formed by the inoculation of the sporidia obtained by the germination of the teleutospores of Uredinopsis Pteridis DIET. et HOLW. on Pteridium aquilinum KUHN var. japonicum NAKAI collected at Sapporo and Nopporo in the Province Ishikari, and at Kaributo in the Province Iburi by the writer, and also at Nioji-yama in the Province Echigo by Miss Homma.
