Journ. Hatrori Bot. Lab. No. 63 : 453-471 (Dec. 1987)

CYTOTAXONOMIC STUDIES OF B.S.G. AND ITS RELATED GENERAl

SATORU INOUE2 AND ZENNOSKE IWATSUKI3

ABSTRACT. Chromosome numbers of 28 taxa of Plagiothecium, Herzogiella, 1sopterygiopsis, /sopterygium, Pseudotaxiphyllum and Taxiphyllum were investigated. Together with previous reports, chromosome numbers of 36 taxa of this taxonomically difficult group of have now been re­ ported. Cytotaxonomically the species of this group are very similar, and they have a similar karyotype formula.

INTRODUCTION The genus Plagiothecium has usually been classified in the family Plagiotheciaceae. Several genera, such as Herzogiella, /sopterygiopsis, /sopterygium, Taxiphyllum, etc. have been generally considered to be related to Plagiothecium. Some bryologists clas­ sify all of these genera in Plagiotheciaceae, while others consider them members of the Hypnaceae. The species of these genera are morphologically very plastic, and difficult to classify. A considerable number of reports on the chromosome numbers of this group have been published (see Table 3). These reports often show different chromosome numbers for the same species. We have been working for years to get cytotaxonomic information for many species from Asia and North America. This information will help immensely toward a more reliable classification of this difficult group of mosses.

MATERIALS AND METHODS Most of the material used for this study was collected by the junior author in various parts of Asia (Japan, Taiwan, North Borneo) and North America (Alaska, British Columbia, Washington) during his bryological surveys. Some material was also added from Japan, Mexico and the United Kingdom by other bryologists. Chromosome numbers of a total of 74 spe­ cimens of various taxa of this taxonomically difficult group of mosses were investigated during the years 1963 to 1987. They belong to 6 genera, 24 species, 2 varieties and 2 form as (Table 1). The living material brought from the field (or sent by air mail) was cultured in the labora­ tory. New shoots developed from the cultured were used for this investigation. Methods for the culture and cytological preparation are the same as those described in our previous

1 Contribution from the Phytotaxonomical and Geobotanical Laboratory, Hiroshima University, N. Ser. 345. 2 Department of Biology, Faculty of Science, Kumamoto University, Kurokami-cho, Kumamoto 860,Japan. 3 Botanical Institute, Faculty of Science, Hiroshima University, Hiroshima 730; also the Hattori Botanical Laboratory, Obi, Nichinan-shi, Miyazaki-ken 889-25, Japan. 454 Journ. Hattori Bot. Lab. No. 63 198 7

TABLE 1. Localities, collectors, and reference numbers of mosses studied.

Chromosome Locality Collector & Species number (n) reference no. Plagiothecium B.S.G. Sect. Plagio thecium P. denticlIlatum 11 U.S.A., Alaska, Peters Lake Iwatsuki & area Steere 3291 11 U.S.A., Alaska, Driftwood Iwatsuki & Steere 1116 11 U .S.A., Washington, Olympic Iwatsuki & Pen., head of Discovery Bay, 15 m Schofield 21 all. 11 U .S.A., Washington, Olympic Iwatsuki & Pen. 5 km W of Townsend Schofield 590 Sect. Lycambium Jed!. P. euryphyllum 11 Japan, Shikoku, Mt. Ishizuchi, Inoue 1658 1800- 1900 malt. 11 Japan, Kyushu, Kumamoto-ken, Inoue & Fujimoto Kikuchi valley 5404 & 5412 11 Japan, Kyushu, Mt. Kirishima, Iwatsuki, 17556, near Lake Ohnami, 1050 malt. 17557, & 17558 P. neckeroideull1 11 Taiwan, between Tong-pu & Iwatsuki & Sharp Pai-mu-lin, foot of Mt. 2356 Morrison, 2500-2900 malt. 11 Japan, Hokkaido, Mt. Oakan, Iwatsuki 10114 400-600 m aI t. P. neckeroideum 11 India, W. Bengal, Darjeeling lwatsuki & var. sikkimense area, Tiger Hill, 8500 ft alt. Sharp 10465 P. undulatum 11 U. K., Wales, Caerns, between Inoue & Smith Pentrefoeks & Betwsycoed W-1 Sect. Saviczia (A. Abr. et I. Abr.) Iwats. P. obtusissimum 1 I Japan, Hokkaido, Mt. Daisetsu Iwatsuki 18442 Nat. Park, above Aizankei, 920-1400 malt. 1I Japan, Hokkaido, Akan Nat. Iwatsuki 18648 Park, Mt. Oakan, 400-600 malt. Sect. Leptophyllum Jed!. P. laetum 11 U .S.A., Olympic Nat. Park, Iwatsuki & Lake Constance trail, 450-1350 m Schofield 502 alt. 11 U.S.A., Washington, Mt. Baker Iwatsuki 2176 Nat. Forest, Mt. Pi1chuk, 900- 1200 malt. 11 Japan, Honshu, Akita-ken, Iwatsuki 20021 Hachimantai, Ohnuma, ca. 800 m alt. Sect. Orthophyllum (Hampe) B.S.G. P. cavifolium 11 Japan, Hokkaido, Is!. Rishiri, Inoue 2310, var. cavifolium Mt. Rishiri 2318, & 2340 S. INOUE & Z. IWATSUKI: Cytotaxonomy of Plagiothecium and related genera 455

TAB LE 1. (Cont.)

Chromosome Collector & Species number (n) Locality reference no. P. cavifolium 11 Japan, Hokkaido, Mt. Daisetsu, Iwatsuki 18458 var.fallax between Aizankei & Numano- & 18461 taira, 920-1400 malt. 11 Japan, Hokkaido, Kushiro-gun, Iwatsuki 18589 forest near Arekinai, 90 malt. P. cavifolium 11 Japan, Hokkaido, Isl. Rishiri, Inoue 2346 f. acuminatum Mt. Rishiri P. nemorale 11 U.S.A., Washington, Olympic Iwatsuki 438 Nat. Park, Sol Duck Hot Spring to Deer Lake, 493-1000 m alt. 11 Japan, Hokkaido, Kamikawa- Inoue 2264 gun, Sohunkyo 11 Japan, Hokkaido, Kamikawa-gun, Iwatsuki 18362 Aizankei-Kumoigahara, 900- 1300 m all. 11 Japan, Honshu, Fukushima-ken, Iwatsuki 20069 Urabandai, Fudohno-taki falls, ca. 900 malt. 11 Japan, Honshu, Mt. Ontake Imae 662 11 Japan, Kyushu, Ohita-ken, Himeno 2725 Shin-yabakei 11 Japan, Kyushu, Miyazaki-ken, Inoue & N ichinan-shi, Kobuze falls Iwatsuki 4844 P. nemorale 1I Japan, Kyushu, Miyazaki-ken, Iwatsuki 17424, f. japonicum Inohae valley, 50-200 m all. 17441 & 17445 11 Japan, Kyushu, Miyazaki-ken, Iwatsuki 10262 Kaeda valley, 20-25 malt. Herzogiella Broth. H. perrobusta 12 Japan, Kyushu, Mt. Kirishima, Iwatsuki 9074 Kurinodake spa, 700 malt. H. seligeri 11 U.S.A., Washington, Olympic Iwatsuki & Nat. Park, Lake Constance Schofield 558 trail, 450-1350 malt. H. turfacea 13 Japan, Hokkaido, Akan Nat. Iwatsuki 18515 Park, Wakoto, side of Lake Kussharo, 120-140 malt. 13 Japan, Hokkaido, Kushiro-gun, Iwatsuki 18584 Beppo, ca. 20 malt. Isopterygiosis Iwats. I. muelleriana 11 Alaska, Kavik camp, SE of Iwatsuki & Prudoe Bay Steere 1148 11 Japan, Hokkaido, Mt. Oakan, Iwatsuki 18650 400-600 malt. 11 Japan, Hokkaido, Kushiro-gun, Iwatsuki 18568 Beppo, ca; 20 malt. 456 Journ. Hattori Bot. Lab. No. 63 1 987

TABLE 1. (Cont.)

Chromosome Locality Collector & Species number (n) reference no. I. pulche/la 11 & 22 Alaska, Kavik Camp, SE of Iwatsuki & Prudhoe Bay Steere 1100 Isoplerygium Mitt. I. albescens 11 N. Borneo, E. Coast, between Iwatsuki 5788 Madai River and Madai Cave, SW of Lahad Datu, ca. 20 malt. 11 Japan, Kyushu, Miyazaki-ken, Iwatsuki & Inoue Kitago-cho, Inohae, 50-200 malt. 4834; Iwatsuki alt. 17428 I. lenerum 12 Mexico, Districto Federal, Delgadillo & Desirto de los Leones Ono Mx-2, Mx- 15, Mx-18 Pseudotaxiphy/lum Iwats. P . arqUlfolium 11 N . Borneo, Mt. Kinabalu, slope Iwatsuki 950 below Sayat, 3()()()-3700 m all. & 1520 11 Taiwan, Mt. Ali, near guest Iwatsuki & Sharp house, ca. 2200 m all. 2148 11 Taiwan, Chia-yi Co., between Iwatsuki & Mt. Al i and Tong-pu, 2200-2500 m Sharp 2525 alt. P . elegans 11 U.S.A., Washington, Olympic lwatsuki & Nal. Park, 490-1 ()()() malt. Schofield 406 11 Canada, Vancouver, the South­ Ono, V7 lands district 11 Canada, British Columbia Hansen 4447 P. maebarae 11 Japan, Honshu, Mt. Kurama Nakajima 3106 near Kyoto, ca. 500 malt. P. pohliaecarpum 11 N. Borneo, E. Coast, Madai Cave, Iwatsuki 5416 30-70 malt. 11 Japan, Ryukyu, Is!. Okinawa, Iwatsuki 11849 Mt. Yonaha, ca. 450 malt. 13 Japan, Kyushu, Mt. Ichifusa Uchino 1215 Taxiphyllum Fleisch. T. alfernans 10 Japan, Honshu, Tokyo, Hama­ Nakamura 3691 rikyu (Detached Palace) 10 Japan, Honshu, Hyogo-ken, Nakajima 3634 Shikama-gun, Maenosho, ca. lOOm alt. T. aomoriense 11 Japan, Honshu, Nara-ken, Nakajima 3547 Yoshino-gun, Dorogawa, ca. 900 m all. 11 Japan, Kyushu, Miyazaki-ken, Iwatsuki 18033 Higashi-usuki-gun, Exper. Forest of Kyushu Uiniv. at Ohkawachi S. INOUE & Z. IWATSUKI: Cytotaxonomy of Plagiothecium and related genera 457

TABLE 1. (Cont.) Chromosome CoJlector & Species number (n) Locality reference no. T. barbieri 11 Java, sine loco Corn. Takaki It-2 T. cuspidi/olium 11 Japan, Honshu, Kyoto, Mt. Nakajima 3026 Kurama, 300 malt. T. taxirameum II India, Darjeeling area, 1500- Iwatsuki & 2000 malt. Sharp 10626 11 Japan, Honshu, Kyoto, Mt. Nakajima 3105 Kurama II Japan, Kyushu, Fukuoka-ken, Inoue 289 Mt. Hiko 11 Japan, Kyushu, Miyazaki-ken, Iwatsuki Inohae valley, 50-200 malt. 17421 & 17430 11 Japan, Ryukyu, Is\. Okinawa, Inoue 2545 Kunigami-gun, Shoshi forest paper (lnoue & Iwatsuki 1976). For the representation of karyotypes, the same symbols as those described in a previous paper (Inoue 1983) are used. Identification of specimens was made by the junior author. Voucher specimens used in this study are deposited in the herbaria of the Hattori Botanical Laboratory (NICH), Botanical Institute, Hiroshima University (HIRO) and the Department of Biology, Kumamoto University.

RESULTS OF OBSERVATION We counted chromosome numbers of 28 taxa of mosses presented in Table 1. Karyotype formulas of these taxa are also shown in Table 2. Among them, chromo­ somes of 11 taxa were newly studied in this work. All known reports of the chromo­ some numbers of this group are listed in Table 3. I. Plagiothecium B.S.G. A genus of about 65 species distributed throughout the world. It is related to Herzogiella and !sopterygium, but is characterized by the thin-walled cortical stem cells, the absence of pseudoparaphyllia, the decurrent leaf bases, and the cylindric or fusiform propagules. We were able to study the chromosomes of most of the species recorded from Japan. Most of material studied in this paper show the same chromo­ some number and the same karyotype formula : n = 11=3V+ 2J+ 6(4v+2j). Two spe­ cies, P. obtusissimum and P. laetum, have the same chromosome number, but show a slightly different karyotype formula from the other species: n = 11 = 4V + 3J + 4(2v+ 2j) and n = 11=5V+ 3J+ 3(2v+j). Jedlicka (1948) classified 10 European species of Plagiothecium s. str. into 5 sec­ tions. In this study, we follow his classification of sections. Karyotype formulas of the species of sect. Plagiothecium, sect. Lycambium, and sect. Orthophyllum are quite similar. 458 Journ. Hattori Bot. Lab. No. 63 1 9 8 7

TABLE 2. Karyotypes of 28 taxa of Plagiothecium and its related genera. Species Sexuality· Karyotype Fig. no. Plagiothecium B.S.G. Sect. Plagiothecium P. denticulatum D&A 11 = 3V + 2J + 6(4v+2j) I-a, 3-A Sect. Lycambium Jed\. P. euryphyllum D 11 = 3V + 2J + 6(4v+2j) I-b, 3-B P. neckeroideum D 11 11 l-c, 3-C P. neckeroideum var. sikkimense D 11 I-d, 3-D P. undulatum D 11 11 l-e, 3-E Sect. Saviczia (A. Abr. & I. Abr.) Iwats. P. obtusissimum D 11 = 4V + 3J + 4(2v + 2j) I-f, 3-F Sect. Leptophyllum Jed\. P.laetum A 11 = 5V + 3J + 3(2v + j) I-g, 3-G Sect. Orthophyllum Jed\. P. cavifolium D 11 = 3V + 2J + 6(4v + 2j) I-h, 3-H P. cavifolil/m var. fallax D 11 11 11 l-i, 3-1 P. cavifolium f. acuminatum D 11 11 11 I-j, 3-J P. nemorale f. nemorale D 11 11 11 l-k, 3-K P. nemorale f. japonicum D 11 11 I-I, 3-L Herzogiella Broth. H. perrobusta A 12 = 3V + 2J + 6(4v + 2j)+m I-m,3-M H. seligeri A 11 11 I-n, 3-N H. turfacea A 13 = 3V + 2J + 6(4v + 2j)+2m 1-0, 3-0 /sopterygiopsis Iwats. l. muelleriana D 11 = 3V + 2J + 6(4v + 2j) 2-a,4-A /. pulchella (n = 11) A? 11 11 2-b,4-B (n = 22) A? 22 = 6V + 4J + 12(8v + 4j) 2-c,4-C /sopterygium Mitt. l. albescens A 11 = 3V + 2J + 6(4v + 2j) 2-d,4-D l. tenerum A 12 = 3V + 2J + 6(4v + 2j)+ m 2-e,4-E Pseudotaxiphyllum Iwats. P. arquifolium D 11 = 3V + 2J + 6(4v + 2j) 2-f,4-F P. elegans D 11 11 2-g,4-G P. maebarae D 11 = 3V + J + 7(4v + 3j) 2-h,4-H P. pohliaecarpum (n = 11) D 11 = 3V + 2J + 6(4v + 2j) 2-i,4-1 (n = 13) D 13 = 3V + 2J + 6(4v + 2j)+2m 2-j,4-J Taxiphyllum Fleisch. T. alternans D 10 = 5V + 2J + 3(2v + j) 2-k,4-K T. aomoriense D 11 = 5V + 3J + 3(2v + j) 2-1,4-L T. barbieri D 11 11 11 2-m,4-M T. cuspidifolium D 11 11 11 2-n,4-N T. taxirameum D 11 11 11 2-0,4-0 • Sexuality: D - dioicous; A - autoicous. S. INouE & Z. IWATSUKl: Cytotaxonomy of Plagiothecium and related genera 459

TABLE 3. Summary of chromosome counts of the species of Plagiothecium and its related genera in the present and previous reports.

Species Sexuality· n References Plagiothecium B.S.G. P. cavi/olium D 10 Yano (1975a, 1975b); Vysotskaya et at. (Syn. P. roeseanum) (1983); Ochyra et at. (1985) 11 Present paper; Danilkiv (1978) ; Inoue (1979) II + m Vysotskaya (1967) 11 + 1 Lazarenko et at. (1971) 20 Al-A ish & Anderson (1960b) P. cavifolium D 11 Present paper var. /allax P. cavifolium D 11 Present paper f. acuminatum P. curvifolium A 11 Smith & Newton (1968) ; Lazarenko et at. (1971); Danilkiv (1978) P. denticulatum D & A 10 Vaarama (1950) ; Yano (1957a, 1957b), Ireland (1969); Bachurina & Solonina (1972) 10 + m Bryan (1973) 11 Present paper; Vaarama (1956) ; Khanna (1967) ; Vysotskaya (1967); Smith & Newton (1968); Ireland (1969) ; Fetisova & Vysotskaya (1970); Fetisova (1970, and in Lazarenko et a t. 1971) ; Snider (1973); Inoue (1974); Danilkiv & Vysotskaya (1983) 20 Anderson & Bryan (1958); Al-Aish & Anderson (1958); Ireland (1969) 25 Anderson & Crum (1958) P. denticulatum 11 Smith & Newton (1968) vac. obtusifolium P. euryphyllum D 10 Inoue & Uchino (1969 as P. sp.) (Syn. P. splendens) 11 Present paper; [noue & Uchino (1969) P.laetum A 10 Ireland (1969) 10+ m Snider (1973 as P. curvifolium) 11 Present paper; Vaarama (1950); Anderson & AI-Aish (1963); Ireland (1969); Fetisova & Vysotskaya (1970); Lazarenko et al. (1971) ; Inoue (1979); Danilkiv (1981) P. latebricola D 10 Visotskaya (1979) (Syn. Plagiotheciella I.) 11 Danilkiv (1978, 1981) P. neckeroideum D 11 Present paper; Inoue (1979) P. neckeroideum D 11 Present paper var. sikkimense P. nemorale D 8 Yano (1957a, 1957b as P. sylvaticum) f. nemorale 10 Yano (1957a, 1957b as P. sylvaticum); Vysotskaya (1967); Wigh (1972, as P. sylvaticum; Danilkiv (1982) 460 Journ. Hattori Bot. Lab. No. 63 198 7

TABLE 3. (Cont.)

Species Sexuality· n References 11 Present paper; Vysotskaya (1967, as P. sylvaticum); Smith & Newton (1968, as P. sylvaticum); Inoue & Uchino (1969, as P. silvaticum); Inoue & Uchino (1969, as P. dentieu/atum); Danilkiv (1978, 1981 as P. sylvatieum); Danilkiv et al. (1983) 12 Inoue & Uchino (1969 as P. silvaticum) P. nemora/e D 11 Present paper; Araki (1963) f. japonicum P. obtusissimum D 11 Present paper P. perminutum 9 Kumar & Verma (1976) P. pili/erum A 11 Vaarama (1950); Ireland (1969) P. p/atyphyllum D or P 10 Vysotskaya (1979) 22 Smith & Newton (1968) P. sueculentum D or P 10 Vysotskaya (1979) 10-11 Lazarenko et al. (1971) 11 Smith & Newton (1968); Danilkiv (1978, 1981); Vorobyev (1979) P. undu/atum D 11 Present paper; Smith & Newton (1968); Ramsay (1969); Ireland (1969); Vysotskaya (1975); Inoue (1979) Herzogiella Broth. (syn. Doliehotheea) H. perrobusta A 11 Inoue (1971) as lsopterygium seligeri 12 Present study H. seligeri A 6 Mohan (1978) A to+ m Bryan (1973) 11 Vysotskaya (1967); Lazarenko et al. (1971) l1 + m Present study H. striatella A 11 Vysotskaya (1979) 11 + m Crum & Anderson (1981) H. tur/acea A 13 Present study 11 Vaarama (1950); Bird (1962 as Plagiothecium tur/aeeum); Vysotskaya (1967 as P. silesiacum) l1 + m Snider (1973) 11 + 2m Present paper !sopterygiopsis Iwats. 1. muelleriana D 11 Present paper; Inoue (1974); Vysotskaya (Syn. !sopteryium m.) et al. (1983) ! . pulchella A? 11 Present paper; Anderson & Crum (1958); (Syn. lsopterygium p.) Khanna (1967) ; Vysotskaya (1975); Inoue (1974) 10 + 2m Bryan (1973) S. INOUE & Z. IWATSUKJ: Cytotaxonomy of Plagiothecium and related genera 461

TABLE 3. (Cont.)

Species Sexuality· n References 22 Present paper; Anderson & Crum (1958); Smith & Newton (1968); Inoue (1974) Isopterygium Mitt. I. albescens A 11 Present paper I. tenerum A 11+1 AI-Aish & Anderson (\960a) (Syn. I. micans) l1 + m Present paper 12 AI-Aish & Anderson (196\) Pseudotaxiphyllum lwats. P. arqul/olium D 11 Present paper P. elegans D 11 Present paper; Smith & Newton (1968); Ireland (1969) ; Newton (197 1) P. maebarae D 11 Present paper P. pallidulum 12 Kumar & Verma (1976) P. pohliaecarpum D 11 Present paper; Inoue (1 964) (Syn. I. textori) l1 + m Chatterjee & Bhaduri (1963) 12 Chatterjee (1964); Inoue (1971) 13 Present paper Taxiphyllum Fleisch. T. alternans D 11 Presen t pa per T. aomoriense D 10 Yano (1957a, 1957b) 11 Present paper T. barbieri D 11 Present paper T. cuspidifolium D 11 Present paper T. taxirameum D 8 Yano (1957b) J 1 Present paper 12 Inoue (1964, 1971) T. wisgrillii D 11 Vysotskaya (1967); Lazarenko et a t. (Syn. T. depressum) (197 J) • Sexuality : D - dioicous; A - autoicous; P - polyoicous.

la. Sect. Plagiothecium P. denticulatum (Hedw.) B.S.G. is widely distributed. It is characterized by dis­ tinctly asymmetric leaves with broadly decurrent bases composed of rectangular, orbicular to round cells. Four specimens from U.S.A. (two from Alaska and two from Washington) have the same chromosome number, n= 11. Previous reports show n = 10, lO + m, 11, 20 and 25 (Table 3). Ireland (1969) described the sexuality of American P. denticulatum as "autoicous, sometimes dioicous". The dioicous population may have n= 10 or 11 chromsomes, while the autoicous population may have n = 20 or 25 chromosomes. 1b. Sect. Lycambium Jed!. This section is characterized by narrow lami nal cells, narrowly decurrent leaf bases, and acute leaf apices. 462 Journ. Hattori Bot. Lab. No. 63 1 987

Specimens of Plagiothecium undulatum (Hedw.) B.S.G. from the U.K., P. euryphyl­ lum (Card. et Ther.) Iwats. from Japan, P. neckeroideum B.S.G. from Japan and Tai­ wan, and P. neckeroideum var. sikkimense Ren. et Card. from India have the same chromosome number n= 11. All previous reports for P. undulatum (Smith & Newton 1968, et a\., see Table 3) are n= 11. Inoue and Uchino (1969) reported n= 10 for P. euryphy/lum. Sexuality of all four taxa mentioned above is dioicous. lc. Sect. Saviczia (A. Abr. et I. Abr.) Iwats. This section includes only one species, P. obtusissimum Broth. from northern Japan and the Soviet Far East, and is characterized by narrow laminal cells, obtuse leaf apices, and inner peristome teeth. Two specimens from Hokkaido, Japan have the chromo­ some number n = 11 . Sexuality of this species is dioicous. Id. Sect. Leptophyllum Jed\. This section is characterized by small to medium-sized plants with flat leaves and monoicous inflorescences. Two specimens of Plagiothecium laetum from western North America (Washington) have a chromosome count of n= 11. We confirmed that the plants were autoicous in the specimen from Mt. Pilchuck, Mt. Baker Nat. Forest (col\, Iwatsuki 2176). le. Sect. Orthophyllum Jed\. This section is characterized by the nearly symmetrical, concave leaves and the decurrent leaf bases with more or less elongate cells. Seven specimens of Plagiothecium cavifolium (including two varieties) from Japan have a chromosome count of n = 11. Some previous reports (Danilkiv 1978, Inoue 1979) agree with the n = 11 count in our study, but Yano (1975a, 1975b) reported n= lO, Vysotkaya (1967) n=1 1+ m and Al­ Aish & Anderson (1960) reported n = 20. Six specimens (five from Japan and one from the western United States) of P. nemorale and four specimens of P. nemorale f. japonicum from Japan have a chromo­ some count of n= 11. Some previous reports for P. nemorale (lnoue & Uchino 1969, etc.) agree with the present report, but different counts have been reported in the past: n = 8 (Yano 1957a, 1957b) ; n= 1O (Yano 1957a, 1957b; Vysotskaya 1967) and n= 12 (lnoue & Uchino 1969). 2. Herzogiella Broth. Herzogiella is a small genus, composed of five species widely distributed in the world. H. perrobusta (Broth. et Card.) Iwats., an endemic species to the Far East (Japan and Korea) has a chromosome number ofn= 12(lI+ m). H. se/igeri (Dix.) Iwats. is distributed widely in the Northern Hemisphere. It has the same chromosome number (n= 12 = Il + m) and karyotype as H. perrobusta. H. turfacea (Lindb.) Iwats. is distributed widely in the Northern Hemisphere. Two specimens from Japan have a chromosome number of n= 13 (11 + 2m), and therefore differ from previous reports : n= 11 (Vaarama 1950 ; Brid 1962); n= ll+m (Snider 1973). All three species studied are autoicous. As shown in Table 2, the karyotype for- S. INOUE & Z. IWATSUKJ: Cytotaxonomy of Plagiothecium and related genera 463

J, l-­ IJ ~( ,'., \ ~ f ·~I_'·'" e Q

o FIG. 1. Mitotic metaphase or anaphase chromosomes in gametophytes. a, Plagio­ thecium denticulatum (n = 11). b, P. euryphyl/um (n = 11). c, P. neckeroideum (n = 11). d, P. neckeroideum var. sikkimense (n = I1 ). e, P. undulatum (n = 10. f, P. obtusissimum (n = II). g, P. laetum (n = II.). h, P. cavifolium (n = 11). i, P. cavifolium var. fal/ax (n = I1). j, P. cavifolium f. acuminatum (n = I1). k, P. nemorale (n = II). I, P. nemorale f. japonicum (n = 11). m, Herzogiella perrobusta (n = 12). n, H. seligeri (n = 12). 0, H. turfacea (n = 13). Arrows show the m-chromosomes. Scale = 5 p.m. mulas of these three species are similar but different in the number of small "m" chro­ mosomes. 464 Journ. Hattori Bot. Lab. No. 63 198 7 •

,;

I •

FIG. 2. Mitotic metaphase or anaphase chromosomes in gametophytes. a, lsoplery­ giopsis muelleriana (n = 11). b, c, l . pulchella (n = 11 & 22). d, lsopterygium albescens (n = 11). e, l. tenerum (n = 12). f, Pseudotaxiphyllum arqui/olium (n = 11). g, P. elegans (n= 11). h, P. maebarae (n = l1). i, j, P. pohliaecarpum (n = l1 & 13). k, Taxiphyllum alternans (n= 10). 1, T. aomoriense (n = 11). m, T. barbieri (n = l1). n, T. cuspidi/olium (n = l1), the smallest chromosome dividing into two chromatids precociously. 0 , T. taxirameum (n= 11). Arrows show the m-chromosomes. Scale = 5 pm. S. INOUE & Z. IWATsuKI: Cytotaxonomy of Plagiothecium and related genera 465

3. lsopterygiopsis Iwats. This small genus is similar to lsopterygium and Plagiothecium. It has some unique characters distinguishing it from related genera, such as well differentiated cortical stem cells (easily seen in cross-section of stem), papillose rhizoids in the leafaxils (all other genera of this group have rhizoids originated from the cells below the leaf insertion), and 2- 5-celled linear propagules in the leafaxils. Only one species, 1. muelleriana (Schimp.) Iwats. has been recorded from various regions of the Northern Hemisphere (Ochyra 1976). However, lsopterygium pulchellum (Hedw.) Jaeg. et Sauerb. has the same unique characters mentioned for /. muelleriana and it is better to transfer it from 1sopterygium to lsopterygiopsis (Iwatsuki 1987). 1. muelleriana has a chromosome count of n = 11. This number is the same as previous reports (Inoue 1974 ; Vysotskaya et al. 1983). A population of /. pulchella from Alaska (Kavik Camp, SE of Prudhoe Bay, coli. Iwatsuki & Steere 1100) has two different chromosome counts: n= 11 and n = 22. Previous reports also show three different chromosome counts: Anderson & Crum (1958), Khanna (1967), and Vysotskaya (1975) for n = ll ; Bryan (\973) for n= IO + 2m; and Anderson and Crum (1958) and Smith & Newton (1968) for n= 22. The junior author confirmed the sexuality of the voucher specimens of /. mue/­ leriana (coli . Iwatsuki & Steere 1148, coil. Iwatsuki 18650, 18568) as dioicous. The voucher specimen of l. pulchella is scanty material but contains at least some autoicous stems. 4. 1sopterygium Mitt. A large genus of more than 200 species distributed throughout the world. I watsuki and Crosby (\ 979) selected 1. tenerum (Sw.) Mitt. as the lectotype of the genus. Iwatsuki (1963) reported filamentous pseudoparaphyllia on the stems of some species of 1so­ pterygium while other species lacked pseudoparaphyllia. These two groups are also different in the characters of propagules. The junior author believes they should be taxonomically distinguished at the generic rank (Iwatsuki 1987). The group of species with fi lamentous pseudoparaphyllia belongs to 1sopterygium. The other group of spe­ cies without pseudoparaphyllia belongs to Pseudotaxiphyllum Iwats. 1. tenerum, distributed in North, Central and South America has a chromosome number of n= 12. 1. albescens, distributed in tropical to subtropical areas in Asia has a n = 11 chromosome number. Both species are autoicous and have a similar karyotype formula, differing in the presence or absence of an "m" chromosome.

5. Pseudotaxiphy llum Iwats. (See Iwatsuki 1987) Pseudotaxiphyllum arquifolium (Bosch et Lac.) Iwats. distributed in tropical to subtropical areas has chromosome number of n = 11, and the same karyotype formula as P. elegans which is widely distributed in Europe and North America. P. pohliaecar­ pum (Sull. et Lesq.) Iwats. is a common species in eastern Asia, and has two chromo­ some numbers, n = 11 and n= 13. The karyotype formula of n= 11 is same as that of P. maebarae (Sak.) Iwats., an endemic species to Japan. This formula, n = 11 = 3V + 466 Journ. Hattori Bot. Lab. No. 63 1 9 8 7

G H I *' •

J K

, M N ., o FIG. 3. Photomicrographs of the mitotic metaphase or anaphase chromosomes in gametophytes. A, Plagiothecium denticulatum (n = l1). B, P. euryphyllum (n = ll). C, P. neckeroideum (n = l1). D, P. neckeroideum var. sikkimense (n = l1). E, P. undulatum (n = l1). F, P. obtusissimum (n = l1). G, P. laetum (n = ll). H, P. cavifolium (n = II). I, P. cavifolium var./allax (n = 11). J, P. cavi/olium f. acuminatum (n = 11). K, P. nemorale (n = l1). L, P. nemorale f. japonicum (n = l1). M, Herzogiella perrobusta (n = 12). N, H. seligeri (n = 12). 0, H. tur/acea (n= 13). Scale = 5 I'm. S. INouE & Z. IWATSUKI: Cytotaxonomy of P/agiothecium and related genera 467 • A B .. c

D

G H I

/, J K L

~ M N o FIG. 4. Photomicrographs of the mitotic metaphase or anaphase chromosomes in gametophytes. A, lsoplerygiopsis muelleriana (n = II). B, C, I. pu/chella (n = I1, 22). D, 1sopterygium albescens (n = 11). E,l. lenerum (n = 12). F, Pseudolaxiphyllum arquifolium (n = I1). G, P. e/egans (n=ll). H, P. maebarae (n = l1). I, J, P. pohliaecarpum (n = 11, 13). K, Taxiphyllum a/lemans (n = JO). L. T. aomoriense (n = II). M, T. barbieri (n = I1). N, T. cuspidiJolium (n=IJ), the smallest chromosome dividing into two chro­ matids precociously. 0, T. taxiphyllum (n = 11). Scale = 5 pm. 468 Journ. Hattori Bot. Lab. No. 63 198 7

J + 7(4v + 3j), is slightly different from those found in many other species of this group which are n= II = 3V+ 2J + 6(4v + 2j). The karyotype formula of the n = 13 of P. pohliaecarpum is essentially the same as that of the n= 11 plants but it has two m-chromosomes. It is quite interesting to note that, as far as the chromosome numbers of the spe­ cies investigated are concerned, species of Isopterygium are autoicous, while those of Pseudotaxiphyllum are dioicous, although chromosome numbers of the species of both genera are the same, except a race of P. pohliaecarpum (n= 13). 6. Taxiphyllum Fleisch. Less than 10 species are known in the world. Some species, T. alternans, T. cuspidi­ folium, and T. taxirameum, are distributed mainly in eastern Asia and eastern North America. The genus is related to Isopterygium, but is characterized by small, thick­ walled cortical stem cells, foliose pseudoparaphyllia, and non-decurrent leaf bases. All species studied are dioicous. T. alternans (Card.) Iwats. has been recorded from Korea, Japan, and the eastern United States. Two specimens from Japan show n = 10. The karyotype formula of this species is n= 10 = 5V + 2J + 3(2v + j). Taxiphyllum barbieri (Card. et Copp.) Iwats. is an aquatic usually cultivated in aquariums with tropical fishes. It probably originated from some area in tropical Asia. A specimen from Java shows a chromosome number and karyotype formula of n = 11 = 5V + 3J + 3(2v + j). Taxiphyllum aomoriense (8esch.) Iwats. (two specimens) and T. cuspidifolium (Card.) Iwats. from Japan, as well as T. taxirameum (Mitt.) Fleisch. from India and Japan (6 specimens), show a chromosome number and karyotype formula of n= 1I = 5V + 3J + 3(2v+ j). This karyotype formula is common with Plagiothecium laetum. Yano (1957a, b) reported n = 10 for T. aomoriense. Yano (1957b) reported n = 8 for T. taxirameum while Inoue (1964, 1971) reported n= 12 for the same species.

DISCUSSIO I. Chromosome numbers and karyotype formulas Chromosome numbers of the species of Plagiothecium, Isopterygiopsis, Isopte­ rygium, Pseudotaxiphyllum, and Taxiphyllum which were investigated in this study are mostly n = 11, rarely n= 10 (see Table 2). Taxa of Herzogiella also have similar chromsome numbers: n = I1 + one or two m-chromosomes. However, previous reports of chromosome numbers of the species of this group include some different numbers, such as n= 8, 9, 10 for Plagiothecium, n = 12 for Isopterygium, n = 13 for Pseudotaxiphyl­ lum, and n= 8, 10, 12 for Taxiphyllum (see Table 3). Chromosome numbers obtained in the present study are more uniform for these genera. The genus Herzogiel/a has been considered very closely related to, or congeneric with, !sopterygium. However, the present study of their chromsome numbers reveals that they may not be so closely related. Species of Herzogiella have n = 12 or 13, while those of !sopterygium have n = 11 or 12 (with n = I I the most common). S. INouE & Z. IWATSUKI: Cytotaxonomy of Plagiolhecium and related genera 469

Karyotype formulas of n= II species of Plagiothecium, /sopterygiopsis, /sopte­ rygium, and Pseudotaxiphyllum are quite uniform : mostly n = ll = 3V + 2J+ 6(4v+ 2j) or its variations with one or two m-chromosomes. However, karyotype formulas of the species of Taxiphyllum are different from those genera: n = 11 = 5V + 3J + 3(2v + j) or its variant. Morphological characters, such as foliose pseudoparaphyllia, short capsules, etc. suggest its close relationship to members of the Hypnaceae. 2. Sexuality and chromosome numbers of Plagiothecium and related genera Iwatsuki (1985) discussed chromosome numbers of the species of Fissidens and their sexuality. He pointed out that species of subgenera Serridium and Pachyfissidens of the genus Fissidens are characterized by a chromosome number of n = 12 for the dioicous species, in contrast to n = 10 or n = 12 in the autoicous species in subgenera Aneuron and Fissidens. He also showed a similar relationship between chromosome numbers and sexualities in Ditrichaceae, Seligeriaceae, and Dicranaceae. A similar relationship was also found in Plagiothecium and its related genera. In Plagiothecium, species of sect. Lycambium, Saviczia and Orthophyllum are characterized by n = 11 for dioicous species, while sect. Leptophyllum has the same chromosome number for autoicous species. It is interesting to note that the genus Isopterygium is characterized by n= 11 or 12 for autoicous species, while species of Pseudotaxiphyllum have n = 1I or 13 for dioicous species. All three species of Herzogiella examined have autoicous plants with a chromosome numbers of n = 12 or 13.

ACKNOWLEDGMENTS. Grateful acknowledgment is made of the financial support for this study provided by a G rant-in-Aid for scientific research by the Ministry of Education, Science and Culture, Japan. We wish to express our sincere thanks to Dr. A. J. Sharp, Dr. W. C. Steere, D r. W. B. Schofield, Mr. T. Nakajima, D r. K. Ono, and other colleagues who helped us in collecting material. Many thanks are also due to Dr. R . R. Ireland for reading the manu­ script, and to Miss M. Fujimoto, Mr. Y. Morita, Mr. Ikemoto, and Mr. T. Himeno for their help in the cytological preparations in this study.

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