Abstracts of APG Vol. 56(1)

Major Evolutionary Advances in the History of Green Land Plants

KLAUS KUBITZKI

University of Hamburg, Germany

The emergence of terrestrial plant life about 500 m ys ago is testified by liverwort-like and later moss-like tissue fragments consisting, i.a., of sporopollenin-containing spore walls and waxy cuticles. Macrofossils from the Early Devonian represent low patch-forming land plants that retained bryophyte-characteristics but had branched sporophytes and contained VA-mycorrhiza-like endophytes. Impregnation of cellulosic cell walls by lignin made possible the construction of larger plant bodies exploiting the light/air-space. At the same time the earliest lycophytes appeared, documenting the split of this lineage from the line leading to the remaining green land plants. In the Late Devonian progymnospermous trees appeared in which pseudomonopodial branching was superseded by lateral branching. The acquisition of the seed habit in the seed fern lineage was probably followed by the still problematic transition from the homorhizic pteridophyte organisation to the allorhizic seed plant organisation, the latter also implying axillary branching. During the Carboniferous, in different lineages strange tree constructions evolved, deriving mechanical strength from root mantles, tubular stems, or periderm tissue, yet nearly all of these lineages, at latest by the Permian, succumbed to the shrinking of wetland habitats. The interval from Permian to Mid Cretaceous was mainly a period of variation of the gymnosperm theme, with the rise and demise of several seed fern and other gymnospermous groups. It is most probable that the rise of the angiosperms was mainly due to their flexible developmental system, which permitted, i.a., the evolution of short-lived herbaceous plant bodies and "cheap" seeds.

　　　　　　 The phenomenon of "unequal" split, i.e. the difference in number of taxa between sister groups, leads to the notion that evolutionary success is hardly predictable. Instead, evolutionary success seems to depend on the coincidence between the accumulation of interactive traits in a lineage and a benign constellation of environmental opportunities. This is exemplified by the spread of modern filicalean ferns, which diversified during the Cretaceous in the shadow of the angiosperms.

Origin and Evolution of "Plants" as Deduced from Genome Information

HISAYOSHI NOZAKI

Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

Phylogenetic relationships between three lineages of the primary photosynthetic eukaryotes (red algae, green plants and glaucophytes) seemed to remain unresolved because previous nuclear multigene phylogenies used the incomplete red algal gene sequences.　 Recently, we carried out phylogenetic analyses based on a 1525-amino-acid sequence of four concatenated nuclear genes from various lineages of only mitochondria-containing eukaryotes, using complete genome sequences from the red alga Cyanidioschyzon merolae.　 This study resolved two large monophyletic groups (groups A and B) and the basal group (Amoebozoa).　 Group A corresponded to the Opisthokonta (Metazoa and Fungi), whereas group B included various primary and secondary plastid-containing lineages (euglenoids, heterokonts, and apicomplexans), Ciliophora, Kinetoplastida, and Heterolobosea.　 The red algae represented the most basal lineage within group B.　 Since the single event of the plastid primary endosymbiosis was strongly suggested by other data, it was considered that the primary plastid endosymbiosis likely occurred once in the common ancestor of group B, and the primary plastids were subsequently lost in the ancestor(s) of organisms which now lack primary plastids within group B.　 A new concept of “Plantae” was proposed for phototrophic and nonphototrophic organisms belonging to group B, on the basis of the common history of the primary plastid endosymbiosis.　

Plant Inventory Research: Contributions to the Flora of Myanmar

NOBUYUKI TANAKA

Kochi Prefectural Makino Botanical Garden, Godaisan 4200-6, Kochi City, Kochi, Japan

The Makino Botanical Garden and its associated institutions have been conducting plant inventory research for contributions to the Flora of Myanmar, based on a memorandum of understanding signed by Makino and the Forest Department, Ministry of Forestry of Myanmar. Current our inventory field research of Myanmar is presented here. Field studies have focused on 2 sites, Mt. Popa and Natma Taung (Mt. Victoria) National Park. Checklists to the flowering plants of these two mountains are currently being prepared respectively based on the collections we have amassed so far. We have also organized training programs to help build capacity amongst our counterparts in Myanmar. For the continued success of collaborative floristic work in Myanmar, a local research centre is required to serve as a herbarium and to promote education on issues such as taxonomic botany.

Musa azizii, a New Musa Species (Musaceae) from Northern Borneo

MARKKU HÄKKINEN

Helsinki University Botanical Garden. P.O. Box 44, Fin-00014 University of Helsinki, Finland.

A new wild banana species, Musa azizii Häkkinen, is described and illustrated. The species is extremely rare, originating in the Lumut Range area of Sarawak, East Malaysia.

Carex semihyalofructa, a New Species of Carex Sect. Rarae (Capitellatae) from Japan

TAKAHIRO SHIMIZU

3-2-1 Uozaki-nakamachi, Higashinada-ku, Kobe 658-0083

Carex semihyalofructa is described as new based on a specimen collected at Mt. Kurikoma, Akita Prefecture, Japan. Though similar to Carex fulta, C. onoei and C. uda, C. semihyalofructa is clearly distinguished by its nerveless and beakless utricles, creeping rhizomes and by the wide space that surrounds the achenes in their utricles. C. semihyalofructa occurs throughout central and northern Honshu, along the Japan Sea side from Fukui to Akita Prefectures.

Return from the Lost: Rediscovery of the Presumed Extinct Leptosolena (Zingiberaceae) in the Philippines and its Phylogenetic Placement in Gingers

HIDENOBU FUNAKOSHI¹*, W. JOHN KRESS², JANA SKORNICKOVA³, AIZHONG LIU² and KEN INOUE⁴

¹Department of Environmental System Science, Graduate School of Science and Technology, Shinshu University, 3-1-1 Asahi, Matsumoto 390-8621 Japan; ²Department of Botany, MRC-166, United States National Herbarium, National Museum of Natural History, Smithsonian Institution, P. O. Box 37012, Washington, D.C. 20013-7012 USA; ³Department of Botany, Charles University, Benatska 2, 128 01, Prague, Czech Republic; ⁴Biological Institute and Herbarium, Faculty of Science, Shinshu University, 3-1-1 Asahi, Matsumoto 390-8621 Japan

The genus Leptosolena currently accepted as monotypic and endemic to the Philippines, has been considered as an imperfectly known genus due to the description based on insufficient herbarium materials for describing floral characters and no recent collection. Our rediscovery of L. haenkei has made it possible not only to describe the species in more depth from fresh materials and to compare with the uncertain second species, L. insignis, more precisely, but to clarify the phylogenetic position among Zingiberaceae with molecular data. Our results support the former treatment that L. haenkei and L. insignis are conspecific, resulting in L. insignis as a later synonym. The lectotype of L. haenkei is chosen among Haenke’s historical collections deposited at PR and PRC.　 Results from DNA sequence data of the ITS and matK loci demonstrate that Leptosolena forms a clade with Vanoverberghia and Alpinia species from the Philippines and Oceania.

Mitochondrial DNA of Phytophagous Insects as a Molecular Tool for Phylogeographic Study of Host Plants

KYOKO AOKI¹, MAKOTO KATO² and NORIAKI MURAKAMI¹

¹Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan; ²Graduate School of Human and Environmental Studies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan

Our purpose is to reveal the detailed postglacial colonizing routes of broad-leaved evergreen forests from the refugia in the Quaternary. In this study, to obtain results, we used intraspecific variations in mitochondrial DNA (mtDNA) of phytophagous animals for the phylogeographic study of their host plants. The mtDNA of the phytophagous insect Curculio hilgendorfi had a greater amount of intraspecific variation than that of the cpDNA of the plants growing in the same Castanopsis-dominant forests. Minimum spanning network of the mtDNA haplotypes showed that haplotypes of primordial origin were geographically quite widespread; whereas those of recent origin were restricted to one or a few localities. Therefore, the phylogenetic information among the mtDNA haplotypes will be useful for the phylogeographic study of C. hilgendorfi. Such patterns were not seen in plant cpDNA haplotypes.

　　 The host-parasite relationship between Castanopsis and C. hilgendorfi also proved to be very tight in this study. If the phylogeographic congruency between phytophagous insects and their host plants could be demonstrated, information about intraspecific mtDNA variation in the phytophagous insect C. hilgendorfi would be very useful for the phylogeographic study of Castanopsis type broad-leaved evergreen forests in Japan.

Allozyme Types of Water Fern Azolla japonica and its Relatives (Azollaceae) Growing in Japan

TAKESHI SUZUKI¹, IWAO WATANABE² and TAKUMI SHIRAIWA³

¹Division of Biological Resources, Institute of Nature and Environment, University of Hyogo, 6 Yayoigaoka, Sanda 669-1546, Japan, ²6-58-18 Jindaiji-kita-machi, Chofu 182-0011, Japan, ³4-7-21-507 Tsurukabuto, Nada-ku, Kobe 657-0011, Japan

Samples of the aquatic floating fern Azolla japonica and its relatives (sect. Azolla) growing in 73 localities of Japan were analyzed by allozyme electrophoresis. Six allozyme types were recognized: AW, BW, BZ, TA, TO and YA types. Compared to the International Rice Research Institute (IRRI) accessions of Azolla by allozymes, the BI and BZ types had the same allozyme patterns as those of A. caroliniana and an artificial hybrid Azolla, respectively; It was supposed that both types had escaped from Azolla introduced to Japan for agricultural use on rice fields. The YA and AW types had very similar allozyme patterns to those of A. filiculoides and A. microphylla, respectively. The TA and TO types shared all allozyme bands except one. The TA and TO types were suggested to be closely related to A. rubra by allozyme comparison. Morphologically, it was suggested that numbers of septa in glochidia (spikelets on male massulae) differentiates the TA type from A. rubra, although only one sample of the TA type was observed. The TA (and possibly TO) type might be an independent species of genus Azolla, or true A. japonica.

Cytogeography of the Adiantum pedatum Complex (Pteridaceae, Subfamily Adiantoideae)

NARUMI NAKATO1 and MASAHIRO KATO2

1Narahashi 1-363, Higashiyamato, Tokyo 207-0031, Japan; 2Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan

A chromosomal survey revealed that Japanese populations of the Adiantum pedatum complex (Pteridaceae, subfamily Adiantoideae) include four cytotypes: diploids of 2n = 58 (x = 29) and 2n = 60 (x = 30), and tetraploids of 2n = 118 and 2n = 120 (x = 30). The few North American plants we analyzed were diploid (2n = 58) and triploid (2n = 87 (x = 29)). The two tetraploid cytotypes in Japan and the triploid from Canada are new cytotypes for this complex. In Japan, diploids with 2n = 60 are widely distributed at all elevations throughout Hokkaido, Honshu and Shikoku. Diploids with 2n = 58 are known from only two lowland sites in eastern Hokkaido. Tetraploids plants with 2n = 118 and 120 are rare in the high mountains of central Honshu and tetraploid plants with 2n = 118 are known from a lowland site in central Hokkaido. Asian members of the A. pedatum complex have a base chromosome numbers of both x = 29 and 30, whereas North American plants are known to have only x = 29 as a base number. Since x = 30 is considered to be ancestral in Adiantum, it is inferred that the x = 29 cytotype in the A. pedatum complex originated in Asia and plants with this number later migrated to North America. Other possibilities are that plants with x = 30 went extinct in North America, or they have yet to be found.

Cytogeography of the Aster ageratoides Complex (Asteraceae) in Korea

AKIKO SOEJIMA¹, JAE-HONG PAK², TATSUYOSHI MORITA³ and MOTOMI ITO⁴

¹ College of Integrated Arts and Sciences, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan; ² Department of Biology, College of Natural Science, Kyungpook National University, Taegu 702-701, Korea;

³ Biological Institute, Faculty of Education and Human Science, Niigata University, Niigata, 950-2181, Japan;

⁴ Department of General Systems Studies, Graduate School of Arts and Sciences, Tokyo University, Tokyo 153-8902, Japan

This is the first report on chromosome number of the Aster ageratoides complex in Korea, which is one of the representatives of Sino-Japanese elements. Our cytogeographical research reveals that both diploids and tetraploids occur in Korea. Diploids are dominant and widely distributed through Korea including Cheju Island, while tetraploids are limited to the southeastern part of the Korean Peninsula. The leaf shape of diploids shows a clinal variation from lanceolate to ovate toward south. At the south end of this peninsula, lanceolate leaved diploids and ovate leaved diploids are sometimes sympatric in several populations. Tetraploids also have a leaf shape variation from lanceolate to ovate even within a population. The plants with elliptic-lanceolate or lanceolate leaves are identified as Aster ageratoides var. ageratoides. Although a taxonomical treatment still waits for further consideration, the resemblance between the ovate leaved plants in Korea and A. ageratoides var. ovalifolius, known as endemic to Japan, is noted.

Two New Putative Natural Hybrids in Japanese Arisaema (Araceae)

TOMIKI KOBAYASHI¹, JIN MURATA² and KUNIAKI WATANABE³

¹583-36, Ookuradanisimizu, Akashi, 673-0865, Japan, ² Botanical Gardens, Graduate School of Science, The University of Tokyo, 3-7-1, Hakusan, Bunkyo-ku, Tokyo, 112-0001, Japan, ³Department of Biology, Faculty of Science, Kobe University, 1-2-1 Tsurukabuto, Nada-ku, Kobe, 657-8501, Japan

Two new putative natural hybrids, Arisaema limbatum Nakai × A. ringens (Thunb.) Schott and A. ovale Nakai var. sadoense (Nakai) J. Murata × A. monophyllum Nakai have been reported.　 The former hybrid was male and the latters female.　 Both hybrids had the combined and/or intermediate gross morphology between their putative parental species with distinct external morphology, and were easily recognized from their parental species in the field.　 Both putative hybrids were produced by parents with different chromosome numbers of 2n = 26 and 2n = 28 in the former combination, and with 2n = 52 and 2n = 28 in the latters, respectively.　 And the pollen stain-ability in the former hybrid was the lowest (32.6%) among the hybrids previously reported.