Propagules of three species of Isopterygium: I. elegans (Brid.) Lindb. from Sweden, I. pohliaecarpum (Sull. et Lesq.) Jaeg. from Japan, and I. maebarae Sak. from Japan were cultured on agar which contains Benecke's solution at 25° ± 1℃. In all three species, propagules were germinated from both ends and formed filamentous secondary protonemata. However, some old, blackish brown propagules of I. maebarae germinated only from the stalk cells which have much thinner cell walls than those of the main bodies. Leafy gametophytes were developed from the secondary protonemata or directly from the upper end of propagules in all three species. Secondary propagules were formed abundantly on the protonemata of I. pohliaecarpum, while no secondary propagules were found in I. elegans during the seven months culture period in the same culture conditions. In I. maebarae, the secondary propagules were formed on the protonemata as well as on young leafy shoots developed on the secondary protonemata. Some other works on similar secondary gemmae formation were reviewed and discussed.

  Cladonia verticillata (Hoffm.) Schaer. is widely distributed in the boreal regions of the Northern Hemisphere, including North America and Europe. Although C. verticillata var. cervicornis (Ach.) Flörke occurs in the high mountains in Honshu, Central Japan, C. verticillata var. verticillata has not been reported from Japan. Recently, Mr. Takahashi sent one specimen to the author, which was collected on Mt. Apoi, Hokkaido in 1972. The specimen was identified as C. verticillata var. verticillata. The identification was made by comparison with European and North American specimens. In the course of the present study, the author found another specimen of C. verticillata in his herbarium. The specimen was previously collected in Sounkyo, Hokkaido, in 1971 by himself. This is the first record of C. verticillata var. verticillata from Japan. C. verticillata occurs in Hokkaido, whereas other Japanese ladder lichens have been collected from Honshu, Shikoku, Kyushu, but not from Hokkaido.

  Cladonia verticillata can be distinguished from the other Japanese allied species (ladder lichens) by morphological characters alone (see fig. 2). In C. verticillata podetia (1.5-2 cm at base of cups) are wider than those (0.9 mm wide) of C. krempelhuberi. In C. verticillata the cortex of the podetia is smooth, while in C. krempelhuberi, the cortex is continuous but somewhat granulose (see Fig. 2f and 2g). C. verticillata can also be distinguished from C. calycantha by the cup-shape (see, fig. 2). Cup margins of C. calycantha expand nearly up to horizontally (ranging from 40° to 90°) to the axis of the podetia, while in C. verticillata the lateral side of the cups flares at 20°-25° to the axis of the podetia.

  Some nomenclatural problems about our populations of C. krempelhuberi and C. calycantha were briefly mentioned, and they were not fully solved yet.

  Thyrea latissima Asah. was newly found on calcareous rocks at the suburbs of Niimi-city , Okayama Pref. This is the second locality for the species.

  Specimen examined. Honshu. Prov. Bitchu: Miyagouchi, Tetsuta-cho, Atetsu-gun. On calcareous rocks; elevation about 200 m, H. Kashiwadani (no. 16736, TNS) and H. Doei.