TITLE: Diatoms from the Hida Mountain Range in the Japan Alps AUTHOR(S): HIRANO, Minoru CITATION: HIRANO, Minoru. Diatoms from the Hida Mountain Range in the Japan Alps. Contributions from the Biological Laboratory, Kyoto University 1972, 24(1): 9 ISSUE DATE: 1972-10-21 URL: http://hdl.handle.net/2433/155990 RIGHT: Contr. Biol. Lab. Kyoto Univ. 24 : 1, Oct. 21. 1972 Diatoms from the Hida Mountain Range in the Japan Alps Minoru HiRANo The Hida Mountain Range consisting of the North and the Central Japan Alps is situated at the central part of Honshu Island ofJapan. This mountain range is about 100 kilometres long from south to north and about 40 kilometres in width. The peaks over 2,OOO metres in altitude are more than 80 in number, 11 of which reach over 3,OOO metres in altitude. The highest, Mt. Okuhodaka-dake, is 3,190 metres above sea level. The Kurobe-gawa River and the Takase-gawa River, the upper streams of the Shinano-gawa River, both known as two of the Iargest streams in this area, divide the range into several mountain groups. The climate is rigorous and during the period from October to May, these moun- tains are usually covered with much snow. Perpetual snow is found in the shaded slopes of the valleys of the high altitude area. There are many swamps, sphagnum-moors and bogs fed by cold water from the melting snow there, and also there are a lot of small alpine lakes and ponds in the high altitude area of Mt. Norikura-dake (alt. 3,026 m), Shirouma-dake (alt 2,933 m), and some other high mountains. The freshwater algal flora and the phytoplanktons are rather poorly found in these alpine lakes in the Japan Alps. The author collected the microscopic algal samples in the area several times during the years from 1942 to 1944 (chiefly the summer materials). Only the desmids found in the samples were already reported in the author's previous article (HiRANo, 1953). The floristic and taxonomic des- criptions of diatoms from the samples of the Hida Mountain Range will be given below. The Japan Alps, covering the high mountainous ranges in the central part of Japan, was named by an English missionary and alpinist, Walter WEsToN (1861-1940), who was one of the pioneers of this beautiful area. It is characteristic of its typical alpine forest of the temperate zone in the Japanese Islands. Although the author's diatom materials from the area is somewhat limited, the study of these materials may certainly contribute to the comparative study and chorological analysis of the alpine diatom flora in the various parts ofJapan. The diatom materials described in the present paper were collected mainly from the alpine ponds and bogs in the sphagnum-moors and the lake-sides of many alpine lakes located at the elevation of over 2,OOO metres line. In the area surveyed, most of the diatom Iocalities are found in the creeping pine (Pinus Pum?ila) zone of the mountain ridge (the lowest distribution ]ine of Pinus pumila in the Japan Alps is about 2,OOO m in altitude). In the vicinity of the source of the Kurobe-gawa River, however, the IO M. HIRANO alpine diatom loca]ities are found in the field of alpine flowers surrounded by the coniferous tree forests. Usually, there is no direct connection of water between the alpine sphagnum-moors and the source of the rivers or streams. As was already pointed out by several diatomists, the diatom flora of sphagnum- moors in Japan consists of the limnophilous species such as the members of the genera Eunotia and Pinnularia, which are the dominant components of the diatom flora of the area. A number of the species of the genera IVeidium, C]mbella and Gomphonema are also common in the alpine region of the Japan Alps, but their distribution range, particularly that of the latter two, is rather limited. The alpine diatom flora in the Japan Alps is quite different from that of the low- ]and areas in the Japanese areas, and is characterized by the northern and alpine species as already reported by some European diatomists. The common species of diatom found in the author's materials are as follows: Eunotia Meisteri and var. bidens, E. perpusilla var. tridentata, *E.parallela, E. Pol-vdentula var. monodon, E. Praeminor var. polaris, E. praemonos var. muscicola, *E. triodon, E. crista-galli, *E. robusta var. diadema, Neidium Perminutum, Caloneis.flasciata, Pinnularia biceLPs and var. minor, P. Carlsoni, P. divergentissima, P. isostauron, *P. islandica, P. stauroptera var. mtnuta, P. subcaPitata var. IaPPonica, P. strePtoraPhe, P. stomatophora, C),mbella alpina, C. heteropleura, *C. hebridica, C. microcephala forma minor, C. PerPusilla, Surirella lapponica. The species with an asterisk in the list are also found in the alpine sphagnum- moors of the Mts. Daisetsu-zan area in the central part of Hokkaido, North Japan (HiRANo and IwAKi, 1970). Some of these widely distributed, alpine species are a)so recorded from the Shiretoko Peninsula in the north-eastern part of Hokkaido (FuKusmMA & KisHiMoTo, 1968). Localities Eighteen stations surveyed are shown in the map of Figure 1. 1. Ponds in Mt. Norikura-dake. Mt. Norikura-dake is an extinct volcano Fig. 1. Map of the Hida Mountains (the Japan Alps) showing the stations survcyed. The arca surrounded bv the curved double lines (heavy solid and thin broken lines) indicates the i Chabu Mountainous National Park. Solid triangles indicate the mountains over 2000 meters above sea level. Stations, Nos, 1-18, see ``Localities'' in the text. The main peaks (a-z) and their altitudes are as follows: a, Mts. Norikura-dake (3026m);. b, Mt. O-nyti-dake (2744m); c, Mt Yake-dake (2455m); d, Mt. Nishi-hodaka-dake (2909m); e, Mt. Oku-hodaka-dake (3190m); f, Mt. Mae-hodaka-dake (3090m); g, Mt. Karasawa-dake (3103m); h, Mt. Kita-hodaka-dake; i, Mt. Yariga-dake (3180 m); J', Mt. J6nen-dake (2857m); k, Mt. Tsubakuro-dake (2763 m); 1, Mt. Sugoroku-dake (2860m); m, Mt. Mitsumata-renge-dake (2841m); n, Mt. Washiu- dake (2924m); o, Mt Kurobe-gor6-dake (2840m); p, Mt. Suish6-dake (2978m); q, Mt. Noguchi-gor6-dake (2924m); r, Mt. Yakushi-dake (2926m); s, Mt. Eboshi-dake (2627m); t, Mt. Harinoki-dake (2821 m); u, Mts. Tateyama (3015 m); v, Mt. Tsurugi-dake (3003m); w, Mt. Kashima-yari-ga-dake (2890 m); x, Mt. Karamatsu-dake (2696 m); y, Mt. Shirouma- ga-dake (2933m); z, Mt. Shirouma-norikura-ga-dake (2437m). Dzatomsfrom the Hzda Mountazn Range zn the JaPan AIPs 11 .ptÅq,..,kX,kreS xy 2okm IX . eqÅr1 sci .f tl jlr'-K( ti5);Årt.:.r'nv 'bl kl1 di '"f ki ge l8 - 12 f .""",XS-:. i. S'gt. 14 th tw"ti v ll 13 15 St'twh.:ilS31mess.sss.."S,:'""Xtfft"w,'gy "f x•dits$-ec ewcwt-s s.ueWeorg:,- ee .,.ganteqts.ee. ll. ec "3oi 12 M. HIRANO located at the southern part oftheJapan Alps (the NorthJapan Alps). This mountain includes several peaks (the highest peak, Mt. Ken-ga-mine, is 3,063.4 m in altitude). There are several alpine lakes such as Gongen-ike, Kame-ga-ike, Turuga-ike, Gono-ike and Ohniu-ike near the top of the mountain (alt, 2,700-3,OOOm). The last one, Ohniu-ike, is located at the lowest position among the alpine lakes of Mt. Norikura-dake and is fed by a stream. The diatom material was collected from the surface of dead leaves in water by a scraping method. 2. Bogs in the Kurobe-goro-taira moor. Kurobe-goro-taira is a col (alt. 2,350 m) located between the ridges of Mt. Kurobe-goro-dake (alt. 2,849.6 m) and Mt. Mitsumata-renge-dake (alt. 2,841.2 m). There are many small bogs in the sphagnum- moors located in the col. 3. Pools in the cirque of Mt. Kurobe-goro-dake. This ``Kar" is located at the eastern slope of Mt. Kurobe-goro-dake. There is a small pool fed by water from the melting snow (the source of the Goro-zawa Valley). 4. A pond at Mt. Mitsumata-renge-dake. This small pond (alt. 2,550m) is located in the col between Mt. Mitsumata-renge-dake and Mt. Washiu-dake (alt. 2,924.2 m). The Iocation is very near from the Mitsumata-renge hut. 5. The Kurobe-genryu-daira moor. Kurobe-genryu-daira is a slope located on the south-western slope of Mt. Jii-dake (alt. 2,821 m). The sphagnum-moor is found between the altitude range from 2,600 to 2,700 metres. 6. A pond at Mt. Eboshi-dake. This is a small alpine lake ]ocated near the top of Mt. Eboshi-dake (alt. 2627m). 7. Ponds and bogs in the Mt. Kami-no-take (also cal]ed Mt. Kitamata-dake) moor. Mt. Kami-no-take is a broad ridge (the highest peak, Mt. Kami-no-take, is 2,662 m in altitude). There are several ponds and many bogs of the sphagnum- moor in the place. 8. Bo.crs in the Tarobei-daira ridge. Tarobei-daira is a broad ridge of gentle slope (alt. 2250 m) near Mt. Taro-yama (alt. 2373 m). There are many small bogs in this place. No direct connection ofwater between each bog and running streams is found. 9. Bogs in Mt. Yakushi-dake (Alt. 2,926m). Mt. Yakushi-dake is located between Mt. Kurobe-goro-dake and Mt. Tateyama (alt. 3015 m). There are several small sphagnum-bogs on the southern slope of this mountain. 10. Bogs in the Kumono-taira plateau. Kumono-taira is a highland plateau located on the south ridge of Mt. Jii-dake. A lot ofsmal] sphagnum-bogs surrounded by the creeping pine and other alpine coniferous trees are found between the altitude range from 2,500 to 2,600 metres. 11. The Kami-no-ta moor of Mt. Shirouma-dake. Kamino-ta is a small sphagnum-moor located on the south-eastern slope of Mt. Shirouma-norikura-dake. There are several small bogs in the shape of terraces in this moor (alt. about 1,700 m). 12. Moor-bogs near Lake Shirouma-6-ike. Lake Shirouma-6-ike (alt. 2,379 m) is a typical alpine lake of the .Japan Alps. It is Iocated on the north-eastern ridge Diatomsfrom the Hida Mountain Range in the Japan Alps I3 ofMt. Shirouma-dake (alt. 2,933 m) and Mt. Shirouma-norikura-dake. A number of sphagnum-bogs are found near the shore of Lake Shirouma-6-ike. 13. Bogs in the Tengu-no-hara plateau. Tengu-no-hara is a wide, east ridge or alpine plateau of Mt. Shirouma-norikura-dake. The altitude range is from 2,200 to 2,300 metres. There are many sphagnum-bogs in the place. 14. The highland moor in the vicinity of the Seijo University hut of Mt. Shirouma-dake. This is a rather small-sized moor and is located on the south-eastern slope of the Tengu-no-hara moor. The Kami-no-ta moor (No. 11) is located at the lower elevation of this moor. There are several small bogs surrounded by the coni- ferous trees in the place. 15. The highland moor ofthe Happo-one ridge. This is located at the eastern ridge or alpine slope ofMt. Karamatsu-dake (alt. 2,696.5 m). A lot ofsmall bogs are found in the moor between the altitude range from 1,700 to I,800 metres. Topograph- ically, most of these bogs are located in the place of the gentle slopes of the ridges. Happo-ike Pond (alt. 2,100 m), a small alpine pond, is located at the highest part of this moor group. 16. Sen'nin-ike Pond. This is a typica] alpine pond located on the east ridge of Mt. Sen'nin-yama (alt. 2,202 m). It is surrounded by the creeping pine trees. Sphagnums grow on the shore of this pond, but the alpine moor is not yet developed around it. 17. A pond oflke-no-taira. This is asmall alpine pond (alt. 2,OOO m) located just below the Ike-no-taira hut. The area around this pond is a rather flat alpine grassland. 18. Kazafuki-kami-no-ta moor and O-ike Pond. Kazafuki-O-ike Pond is Iocated in the wide pass or the alpine plateau surrounded by Mt. Kazafuki-6-dake (alt. 1780m), Mt. Mae-yokokura-dake (alt 1940m) and Mt. Iwasuge-yama (alt. 1780m). Its altitude is 1,778metres. The Kazafuki-kami-no-ta moor contains a number of small bogs located near the pond. Fam. Coscinodiscaceae Melosira distans (EHRENB.) KuTz. in HusTEDT, Krypt. Fl. 7, p. 262, f. 1 10, 1930. Valves 9pa in diameter. Hab. Gono-ike. Distr. Previously known from Mt. Daisetsu. var. Iirata (EHRENB.) BETHGE in HusTEDT, 1.c. p.264, f.i11, 1930. Valves 12pa in diameter. Hab. Ohniu-ike. Distr. Mt. Daisetsu. Cyclotella stelligera CLEvE & GRuN, in HusTEDT, Silssw.-fl. 10. p. 100, f.65, 1930; A. CLEvE, K. V. A. Handl. 2: 1, p. 43, f. 52, 1951. Valves 12pa in diameter. Hab. Gongen-ike, Kurobegoro-daira, Kumono-taira, Tengunohara, and Kurobegorodake. Distr. Shiretoko, Hokkaido. Fam. Fragilariaceae TabeUaria flocculosa (RoTH) KUTz in HusTEDT, SUssw.-fl. 10, p. 123, f. 1Ol, 1930. Valves 25pa long, 7" broad. Hab. Happo-one. Distr. Shiretoko. Diatoma hiemale (LyNGB.) HEiBERG in HLJsTEDT, SUssw.-fl 10, p. 129, f. 115, 1930. Valves 2I," long, 8se broad. Hab. Ohniu-ike. I)J'str. Mt. Daisetsu and Shiretoko. var. mesodon (EHRENB). GRuN. in HusTED'r, 1.c. p. 129, f. 116, 1930. Valves 20,tt long, 7pa broad. Hab. Happo-one. Distr. Mt. Daisetsu and Shiretoko. Ceratoneis arcus KUTz. var. recta CLEvE in KoBAyAsHi, Journ. Jap. Bot, 40, p. 126, f. }-5, 1965. C. recta IwAHAsHi, Journ. Jap. Bot. 12, p. 391, Åíla-c, 1936. Valves 40pa long, 7.5pa broad, and striae 13-14 in 10u. Hab. Ohniu-ike, Norikura. Distr. Arakawa River. ThisspecieswaspreviouslyknownfromRiverArakawa,and I found it only once in a broken specimen. It has probably come to the lake through an income stream. Peronia Heribaudi BRuN. & PERAG. in HusTEDT, Krypt. Fl. 7: 2, p. 202, f. 739, 1932. Valves 22-40rdong, 3-3.5pt broad, and striae 15-16 in 10,u. Hab. Kazafuki-O-ike, Koshiki-ike. Distr. Daisetsu-zan and Shiretoko, Hokkaido. Eunotia alpina (NAG.) HusTEDT in SUssw.-fl. 10, p. 185, Åí 252, 1930. Va]ves 45,a long, 2.5pa broad, and striae 20 in 10pa. The present specimens re- semble E. Iunaris in some respects but differ from it in having narrower valves and a number of fine striae. Hab. Eboshi-dake. Distr. New to Japan. Eunotia arcus EHRENB. in HusTEDT, 1.c. p. 175, f. 216, 1930; A. CLEvE, K.V.A. Handl. 4 : 1, p. 123, f. 463a-d, 1953 (as var. genuina MEisTER). Valves small, slightly arcuate, ventral margin slightly concave and dorsal margin more convex than the curvature of the ventral margin and in some specimens dorsal margin shows a straight side in the middle, valves suddenly narrowed near the ends which are elongated and slightly reflexed, rounded at the extremity so that they give a somewhat capitate appearance; terminal nodules distinct and sited somewhat back on the ventral margin, striae distinct and equidistant. Valves 43-48pa long, 4-5pa broad, and striae 13-14 in 10pa. The present specimens resemble the one, ofwhich the figure was given by HusTEDT in a general appearance but differ from the European forms in the form of the valval encl which is not produced and in the striae arrangement. Hab. Gongen-ike, Gono-ike, Ohniu-ike, Kurobe-goro-daira, Kamino-take, Mitsumata- renge-dake, Eboshi-dake, Kumono-taira, Happo-one, Tenguno-hara, near Shirouma- O-ike. Distr. Daisetsu-zan. var. curvata A. CLEvE in 1.c. 4: 1, p. 123, f. 463, i.j. 1953. Valves small, moderately curved, median part of the valve linear and with the almost parallel sides, gradually attenuated toward the ends which are recurved to the dorsal side, rounded at the extremity, striae distinct 17-18 in 10pa. Valves are 23ps long, 2.5pt broad. The figure by A. CLEvE of the variation of this species shows the Diatomsfrom the Hida Mountain Range in the Japan Alps 15 number of striae of23-25 in 10pa but the present specimens have 17-18 in 10pt. The present specimens resemble somewhat the typical form of this species but differ from it in its narrower valve and its strong curvature and also differ from var. curvata in its shorter valve, the dense arrangement ofstriae and the end that is not capitate. Hab. Gono-ike. Distr. Shiretoko. Eunotia crista galli CLEvE in HusTEDT, Krypt. Fl. 7 :2, p. 294, Åí760, 1932. Valves 38--40," long, 7.5-8pa broad, and striae 13-14 in 10pa. Hab. Happo-one. Distr. Shiretoko. Eunotia exigua (BREB.) GRuN. in A. CLEvE, 1.c. 4:1, p. 106, f. 439, 1953. Valves small, long and narrow, slightly curved, ventral side slightly concave or almost straight, dorsal side slightly convex but recurved near the end, cell slightly narrowed to the ends which are truncate. Valves 28-35pa long, 3-4.5pa broad, and striae 16-18 in IOpa. Hab. Gongen-ike, Kamega-ike, Gono-ike, Happo-one, Taro- bei-daira, Mitsumata-renge-dake, Kurobe-goro-daira, Yakushidake, Kumono-taira, Tenguno-hara, near Shirouma-O-ike, Seijo-hut. Distr. Daisetsu-zan. var. compacta HusTEDT in 1.c. p. 176, f. 225, 1930. Valves 45pa long, 2.5xt broad, and striae 16-17 in 10pa. The end of the valves distinctly capitate, terminal nodules distinct and raphe disposed deep inside of the ventral margin. Hab. Gongen-ike. Distr. Shiretoko. Eunotia fuba (EHRENB.) GRuNT. var. densestriata OsTR. in A. CLEvE, 1.c. 4: 1, p. 1]2, f. 449e, 1953. Valve 15pa long, 5pa broad, and striae 18 in 10pa. Hab. Ikenotal ra. Distr. New to Japan. var. nipponica SKvoRTzow in Philip. .}ourn. Sci. 61, p. 21, pl.14, f. 4, 1936. Valves I2-19,a Iong, 2-3pa broad, and striae 20-28 in 10pa. Valves not capitate at the end. Hab. Kurobe-goro-taira, Tenguno-hara, near Shirouma-O-ike, and Seijo-hut moor. Distr. Daisetsu-zan. Eunotia fctllax A. CLEvE in 1.c. 4:1, p. 99, f. 426a, 1953. Valves small, narrow sublinear, slightly curved, median part linear and parallel on the sides, dorsal side slightly convex and ventral side concave, gradually and rapidly attenuated near the end, ends produced and slightly recurved toward the dorsal side, extremity obliquely truncate, terminal nodules slightly developed, striae distinct, equidistant but denser near the ends. The p'resent specimens resemble E. arcus but the shape of the valval end is different from that of E. arcus which has a recurved, obliquely truncate apex ofthe end. Hab. Kamega-ike. Distr. New toJapan. var. gracillima A. CLEvE in HusTEDT, Krypt. Fl. 7:2, p. 288, f. 753b-e, 1932; A. CLEvE, 1.c. 4:1, p. 99, f. 426b,c, 1953. Dorsal margin convex, ventral margin slightly concave, central part of the valve sublinear, not parallel, gradually attenuated toward the encl, ends slightly dilated, having a truncate apex, so that the end of the valve is slightly capitate, striae rather roughly disposed and equidistant, length ofvalve 17-40pa, breadth 2.5-3.5pa, and striae 10-12 in 10,". The present specimens resemble E. tenella but are distinguished from it in their fewer number of striae. Hab. Tarobei-daira, Mitsumata-renge-dake, Kamino-take, Kumono-taira, southern side of Yakushi-dake, Tenguno-hara, Kurobe- goro-taira. Distr. New to Japan. Eunotia Kocheliensis MuLLER in MAyER, Denkschr. Kgl. Bayer. Bot. Ges. 13, F. N. 7, p. 25, pLl, f. 63, 1915. , var. atpina HiRANo, var. nov. Valvae minores, reni'formes, 5pa longae, 3.5p latae et striae radiatae. The present specimens are shorter and smaller than those of the typical form. Hab. southern side of Yakushi-dake. Eunotia lapponica A. CLEvE in Bih. Kongl. Sv. Vet. Akad. Handl. 21, Afd. 3, no. 2, p. 29, pl. 1, f. 29, 30, 1895; HusTEDT, Krypt. F].7:2, p. 295, f. 762, 1932. Valves of medium size, robust, slightly curved, gradually attenuated from the median part to the ends which are rounded and in some specimens slightly recurved upward, ventral margin slightly concave, dorsal margin convex, striae fine and densely disposed, 20 in 10u, terminal nodules large, raphe well developed and deep in the inner part of the valval end. The present specimens resemble somewhat E. monodon but are distinguished from it in their dense disposition ofstriae. Hab. near Seijo-hut. Distr. Daisetsu-zan. Eunotia lunaris (EHRENB.) GRuN. in HusTEDT, SUssw.-fl. 10, p. 183, f. 249, 1930; A. CLEvE, K. V. A. Handl. 4: 1, p. 88, fi412a,b, 1953 (as var. genuina GRuN.). Valves 50," Iong, 4pt broad, and striae 14-15 in 10,". Hab. Gongen-ike, Kurobe- goro-daira, Kumono-taira, and Tengunohara. Distr. Shiretoko, Mt. Daisetsu-zan. var. nttenuata A. CLEvE in 1.c. 4:I, p. 90, f. 413 p.r. 1953. Valves 29-35pa long, 3.4-4," broad, and striae 18 in 10,". Hab. Eboshidake, Kumono-taira, Tengunohara, and near Shirouma-6ike. var. fctlcata (BREB.) A. BERG in A. CLEvE, 1.c. 4:1, p. 89, fi413c-g, 1953. Valves 20-23pa long, 2.5-3pt broad, and striae 20-22 in 10pt. Hab. Kumonotaira. Distr. N. Europe. ' Eunotia Meisteri HusTEDT in SUssw.-f]. 10, p. I79, f. 230, 1930; A. CLEvE, 1.c. 4:1, p. 111, f.448, 1953. Valves l1pt long, 3.5pa broad, and striae 20 in 10pt. Hab. Tarobei-daira, Eboshidake, Kumonotaira, and Tengunohara. var. bidens HusTEDT in SUssw.-fi, 10, p. 179, Åí231, 1930 Valves 9-10pa long, 3.5pt broad, and striae ca. 20 in 10pa. Hab. Tengunohara, Kaminotake. Distr. Europe. Eunotia paralleta EHRENB. in HusTEDT, SUssw.-fl. 10, p. 183, f. 247, 1930. Valves 47-80pa long, 7.5-9ps broad, and striae 8 in 10pt. Hab. Ohniu-ike, Ten- guno-hara. Distr. Shiretoko, Daisetsu-zan. Diatomsfrom the Hida Mountain Range in the Japan Alps 17 Eunotia pectinatis (KbTz.) RABENH. in HusTEDT, 1.c. p. 180, f. 237, 1930. Valves slightly curved, both sides parallel but gradually and slightly attenuated to the ends which are slightly recurved, ends not capitate, strongly striated, striae 1 1-12 in 10pt. Valves 80pa long, 5.5sL broad. Hab. Ohniu-ike, Happo-one, and Tenguno- hara. Distr. Daisetsu-zan. var. elongata V. H. in A. CLEvE, 1.c. 4:1, p.83, f.409a, 1953. Valves 100pa long, 6pt broad, and striae 11 in 10pa. Hab. Kamega-ike. var. minor (KUTz.) RABENH. in HusTEDT, 1.c. p. I82, Åí 238, 1930. Valves 22/z long, 5pa broad, and striae 15 in 10pa. Dorsal side convex but not fiattened in the middle, ventral side straight and not concave. The present specimens resemble E. sudetica but the number ofstriae is larger than that of the E. sudetica and coincides with that of the E. pectinalis. The breadth of the valve is nearer to the size described by A. CLEvE. Hab. Gono-ike, Happo-one, near Shirouma-6ike. forma impressa (EHRENB.) HusTEDT in 1.c. p. 182, f. 239, 1930. Valves 27pa long, 4pa broad, and striae 17 in 10pt. Hab. Gongen-ike. Distr. Daisetsu-zan. E u n o t i a p e r p u s i l l a ( G R u N . ) A . C L E v E evar. tridentata (MAyER) A. BERG in A. CLEvE, 1.c. 4:1, p. 102, f.430d-f, 1953. Valves rather minute, slender and slightly curved, ends capitate and rounded at the extremity, dorsal margin convex, having three waves, elevations slight and not acute, ventral margin concave, also having three slight waves, striae fine but distinct about 20 in IOpt. Valves 20ps long and 2.5pa broad. These tiny specimens differ some- what from the European forms figured by A. CLEvE. The central elevation on the dorsal margin is acute in the European forms but rounded in my specimens. Also the valves in the present specimens are relatively Ionger than those of the European speci- mens. Hab. Kumono-taira, Tenguno-hara. Distr. New to Japan. Eunotia polydentula (BRuN.) A. BERG var. monodon MAyER in A. CLEvE, 1. c. 4:1, p. IOI, Åí 429f, 1953. Valves rather minute, slightly curved, ventral margin slightly excavated in the mediam part, dorsal margin strong convex without elevation as seen in the typical form, ends capitate and rounded at the extremity. Valves 18pa long, 3.5pa broad, and striae ca. 20 in IOpa. Hab. Southern side ofYakushidake. Distr. New to Japan. Eunotia praerupta EHRENB. in HusTEDT, Krypt. Fl. 7:2, p. 280, Åí 747A:a, 1932. Valves of medium size, slightly curved, dorsal margin strong convex in the middle and refiexed near the end, ventral margin slightly concave or hollow in the middle, valves attenuated from the inflated median part toward the end and abruptly attenuated below the end, ends truncate-convex at the extremity, end part of the valve capitate, terminal nodules distinct and located at the extremity above the ventral side, striae rougb!y arranged and substriated between the complete striae in some specimens. Valves 30pa long, 10," broad, and striae 9-10 in 10pa. Hab. Gono-ike, Mitsumata-