Allozyme analysis of cryptic species in the Asplenium niduscomplex from West Java,Indonesia

In various fern species, a large amount of rbcL sequence variation has been reported, and it is possible that these species contain several reproductively isolated cryptic species. In our previous study on Asplenium nidus L., it was suggested that the plants growing in Mt. Halimun National Park, West Java, Indonesia, consist of several cryptic species based on the results of crossing experiments among rbcL sequence types. In this study, we examined allozyme polymorphisms of five rbcL sequence types found in West Java in order to test the hypothesis that the assemblages of A. nidus delimited based on the rbcL sequences are separate Mendelian populations and gene flow is disrupted by reproductive isolation from one another. The calculated fixation indices suggested that the individuals in each rbcL type are randomly crossing at least in the investigated localities. Nevertheless, these rbcL-based assemblages were genetically differentiated in allozymes that are encoded in their nuclear genomes, and it is also suggested that gene flow is disrupted even between sympatrically distributed pairs of rbcL sequence types. Therefore, our findings support the view that the five rbcL sequence types in West Java are potential cryptic species. Electronic Publication     

Taxonomic studies on Asplenium sect. Thamnopteris (Aspleniaceae) II: spore morphology

Asplenium sect. Thamnopteris is a morphologically distinct group within Asplenium, however, the species delimitation within the section is difficult. To evaluate the utility of spore morphology in the taxonomy of Asplenium sect. Thamnopteris, we examined 64 samples representing ca 25 species using scanning electron microscopy. The results show that the spores are monolete and ellipsoidal in shape, and range between 35.7–50.1 × 24.1–32.4 µm in size. The perispore is morphologically very diverse but relatively stable within species. Based on the morphology of spores, we discuss the species concept of A. nidus L. and A. phyllitidis D. Don, propose a new combination (A. latibasis) for Neottopteris latibasis Ching, and treat A. phyllitidis subsp. malesicum Holttum, N. latibasis, N. latipes Ching ex S. H. Wu, and N. subantiqua Ching ex S. H. Wu as new synonyms. A key to all known species of sect. Thamnopteris is provided using characters of spore morphology.     

The systematic position ofAsplenium cardiophyllum (Aspleniaceae)

Asplenium cardiophyllum is a morphologically unusual species with simple leaves and anastomosing venation, and is often placed in the segregate genusBoniniella. To determine its systematic position, character comparisons were made of vascular anatomy, raphides in leaf epidermis, chromosome number and perispore of this species and those ofAsplenium sect.Hymenasplenium. Asplenium cardiophyllum conforms with sect.Hymenasplenium in its dorsiventral dictyostele, the presence of raphides, a chromosome number of 2n=156 (x=39), and lophate peristore with spinulate projections on the lumina. We therefore propose to includeA. cardiophyllum in that section. Dedicated to the memory of the late Professor Kunio Mitui.     

Patterns of hybrid formation among cryptic species of bird‐nest fern,Asplenium nidus complex (Aspleniaceae), in West Malesia

In order to clarify patterns of hybrid formation in the Asplenium nidus complex, artificial crossing experiments were performed between individuals of genetically differentiated groups based on the sequence of the rbcL gene, including A. australasicum from New Caledonia, A. setoi from Japan and several cryptic species in the A. nidus complex. No hybrid plants were obtained in crosses between nine of the 16 pairs. Even for pairs that generated hybrids, the frequency of hybrid formation was lower than expected given random mating, or only one group was able to act as the maternal parent, when the genetic distance (Kimura's two parameter) between parental individuals was at least 0.006. Sterile hybrids were produced by three pairs that were distantly related but capable of forming hybrids. Considering the results of the crosses together with the genetic distance between the parental individuals, it seems that the frequency of hybrid formation decreases rapidly with increasing divergence. The frequency of hybrid formation has not been previously examined in homosporous ferns, but it seems that a low frequency of hybrid formation can function as an important mechanism of reproductive isolation between closely related pairs of species in the A. nidus complex in addition to hybrid sterility. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 42–63.     

Importance of drought on the distribution of the birds nest fern,Asplenium nidus,in the canopy of a lowland tropical rainforest in north‐eastern Australia

Abstract The birds nest fern, Asplenium nidus, contributes greatly to the epiphytic biomass in the canopies of both south‐east Asia and tropical north Queensland rainforests. It is generally believed that their abundance and their capacity to store water is an important feature for habitat fragmentation in the canopy. We investigated the microclimate of A. nidus and the effects of severe drought periods on the A. nidus population over a 20‐year period, hypothesizing that water availability is the most important factor controlling the population under drought conditions. One of two neighbouring A. nidus plants of the same size and age was irrigated artificially before, during and after a significant dry period in 2000. By monitoring the microclimate within and around both ferns we were able to estimate that four continuous weeks of rainless weather completely dried out the accumulated humus of the non‐irrigated A. nidus fern. Prolonged dry periods were shown to kill the roots of A. nidus, which attach the fern to the bark and eventually the affected A. nidus on verticals stems fell to the ground. Periods longer than 8 weeks may even kill adult plants sitting in more protected branch forks. Analysis of the whole A. nidus population within the 1‐ha Canopy Crane plot and the determination of the morphological age of all plants enabled an evaluation of the historical development of the population. The oldest plant originated in 1985, just 1 year after the longest recorded drought for the site. We suspect that the 1984 drought killed every A. nidus plant within the study plot. Years with low recruitment coincide with years with long drought periods.     

Distributional Patterns of Epiphytic Ferns are Explained by the Presence of Cryptic Species

In a recent article in this journal Zhang and colleagues investigated the factors affecting the distribution of a species of epiphytic fern Asplenium nidus L. in rain forest in Peninsular Malaysia. Here we suggest that their findings may be interpreted in the light of there being two cryptic species present, each with different ecologies, as is the case in Malaysian Borneo. We also discuss the implications of the existence of cryptic species when attempting to conserve forest diversity in the face of climate change and habitat conversion. Abstract in Malay is available at http://www.blackwell‐synergy.com/loi/btp .     

The base number of ��loxoscaphoid�� Asplenium species and its implication for cytoevolution in Aspleniaceae

Background and Aims

‘Loxoscaphoid’ Asplenium species are morphologically a remarkably distinct group of Aspleniaceae. Except for two preliminary chromosome counts of Asplenium theciferum, the cytology of this group of species has, however, been largely unstudied.

Methods

Chromosome counts were obtained by acetocarmine squash preparations of one mitotic cell and several meiotic cells. Relative DNA content of gametophytic and sporophytic cells was determined by flow cytometry. The phylogenetic placement of A. loxoscaphoides, A. rutifolium s.l. and A. theciferum s.l. was investigated through an analysis of rbcL sequences.

Key Results

The dysploid base number is reported to be x = 35 in Asplenium centrafricanum, A. loxoscaphoides, A. sertularioides and A. theciferum. Analysis of rbcL sequences confirms that ‘loxoscaphoids’ nest robustly within Asplenium. Several high ploidy levels exceeding the tetraploid level were found in A. theciferum s.l. and A. rutifolium s.l. All taxa proved to be sexual.

Conclusions

Four base numbers are known at present for Aspleniaceae: x = 39, 38, 36 and 35. The dysploid base number x = 35 found in the ‘loxoscaphoid’ Asplenium spp. sheds a novel light on the cytoevolution of the whole family. We postulate a recurrent descending dysploid evolution within Aspleniaceae, leading to speciation at the (sub)generic and species/group level.     

Factors Affecting the Distribution and Abundance of Asplenium nidus L. in a Tropical Lowland Rain Forest in Peninsular Malaysia

Asplenium nidus is an abundant epiphytic fern of tropical rain forests in the Old World, where it plays an important ecological role in the forest canopy as host to diverse arthropod communities. We investigated the factors that determine the distribution and abundance of A. nidus in the canopy of an aseasonal lowland dipterocarp forest at Pasoh Forest Reserve, Malaysia. We found that A. nidus was more abundant in the understory, and on hosts with smooth bark and relatively flat branch angles. Ferns were found on a wide diversity and size range of host taxa. However, both host taxa and host diameter at breast height had a significant effect on A. nidus occupancy. Asplenium nidus had an aggregated spatial distribution at all scales within the study area. Spatial aggregation at larger scales appears to be driven by habitat preference, as A. nidus abundance was positively associated with swampy areas and negatively associated with hilly areas. At smaller scales, limited dispersal of their wind-dispersed spores most likely explains the aggregated distribution. Larger individuals occurred higher in the canopy and were more common in the hilly area. Thus, the distribution of A. nidus may represent a trade-off between the availability of suitable microsites for establishment in the understory and better growth conditions higher in the canopy. However, A. nidus is known to comprise a complex of cryptic species, and future studies should incorporate molecular techniques to elucidate the potential role of speciation in explaining these patterns.     

New guinea salt fern (Asplenium acrobryum complex): Identity,distribution, and chemical composition of its salt

Fronds of a fern of theAsplenium acrobryum complex were traditionally used as a source of salt in the inland areas of Papua New Guinea. All previously published reports of the use of fern salt in the botanical and ethnobotanical literature had erroneously identified the species involved asAsplenium nidus, one of the common bird’s-nest ferns. A chemical analysis of the salts contained in the ash of the salt fern as well as those species related toAsplenium nidus revealed that the bulk of the inorganic component was potassium, calcium and chloride. These results are comparable to those published for the salt-yielding grass,Coix gigantean. There is no obvious chemical reason why onlyAsplenium acrobryum should be used for salt production in preference toAsplenium nidus and related species. In view of the low levels of consumption of such salt it is unlikely that there will be any cases of potassium toxicity attributable to the use of these plants.     

The distribution of TPX2 in dividing leaf cells of the fern Asplenium nidus

Plant cell division requires the dynamic organisation of several microtubule arrays. The mechanisms of regulation of the above arrays are under rigorous research. Among several factors that are involved in plant microtubule dynamics, the Targeting Protein for Xklp2 (TPX2) has been found to play a role in spindle organisation, in combination with Aurora kinases, in dividing cells of angiosperms. Microtubule organisation in dividing cells of ferns exhibits certain peculiarities. Accordingly, the presence and distribution of a TPX2 homologue might be helpful in understanding the patterns and regulatory mechanisms of microtubule arrays in this plant group. In this study, a putative TPX2 homologue was identified using Western blotting in the fern Asplenium nidus. It was found, using immunostaining and CLSM, that it is co‐localised with perinuclear preprophase microtubules and the prophase spindle, and follows the microtubule pattern during metaphase/anaphase and telophase. During cytokinesis, while in angiosperms TPX2 is degraded, in A. nidus the TPX2 signal persists, co‐localising with the phragmoplast. In early post‐cytokinetic cells, a TPX2 signal is present on the nuclear surface facing the daughter cell wall and, thereafter it is co‐localised with the fern‐specific microtubule aggregation that lines the new wall, which is possibly involved in cortical microtubule assembly.     

Index to new names, combinations and emendation appearing in Mycoscience 51 (2)

In this paper, four fungi collected in Nansei Islands are reported. One is Strasseria garciniae, which must be transferred to the genus Phyllosticta. This fungus was collected in Okinawa Main Island and Iriomote Island. The other three fungi are newly added to the Japanese fungal flora. Phyllosticta ghaesembillae on Codiaeum variegatum and Cercospora asplenii on Asplenium antiquum were collected in Yoron Island. The last one, Coniella australiensis on Eucalyptus robusta was collected in Okinawa Main Island. Their morphology and symptoms on the host plant are described, with some mycological notes.     

Flavonoid variation and evolution inAsplenium normale and related species (Aspleniaceae)

Flavonoid profiles of 132 populations (472 individuals) ofAsplenium normale, and related species,A. boreale, A. shimurae, andA. oligophlebium var.oligophlebium and var.iezimaense in Japan were surveyed by HPLC and 2D-PC. Of the five taxa, each ofAsplenium boreale, A. shimurae andA. oligophlebium including var.iezimaense had consistent flavonoid composition: apigenin 7, 4′-di-O-rhamnoside (9) inAsplenium boreale, 7-O-glucosyirhamnosides of apigenin and luteolin (6 and 7) inA. shimurae and genkwanin 4′-O-glucosyl-rhamnoside (5) in twoA. oligophlebium varieties. On the other hand,Asplenium normale was divided into seven chemotypes A-G: A-type has 7-O-dirhamnosides of apigenin and luteolin (1 and 2) and genkwanin 4′-O-glucosylrhamnoside (5); B-type, 5 alone; C-type, apigenin 7-O-rhamnoside-4′-O-glucosylrhamnoside (8); D-type, 1 and 2; E-type, 1,2 and 8; F-type, 1, 2, 5 and 8; and G-type, 5 and 8. Among them, the most frequent types were A, B and C, and A-type was mainly distributed in inland of Honshu, Shikoku and Kyushu, while B- and C-types extended their distribution areas southwards in general and occur along the Pacific coast with several exception. Chemical and evolutionary relationships amongAsplenium boreale, A. shimurae, A. oligophlebium, and the chemotypes ofA. normale were discussed on the basis of general biosynthetic pathway.     

Hemiboea guangdongensis comb. & stat. nov., a cryptic species segregated from H. subcapitata (Gesneriaceae) based on morphological and molecular data

The taxonomic problem of cryptic species has long been recognized. Hemiboea subcapitata C. B. Clarke is a widespread and morphologically diverse species including two varieties, H. subcapitata var. subcapitata C. B. Clarke and H. subcapitata var. guangdongensis (Z. Y. Li) Z. Y. Li. However, genetic distance and molecular phylogenetic analyses based on nuclear ITS and four plastid DNA sequences (atpB‐rbcL, matK, rbcL, rpS16 intron) revealed that H. subcapitata var. guangdongensis is sister to H. subacaulis, and separated from H. subcapitata var. subcapitata, suggesting that it should be raised to the rank of an independent species as H. guangdongensis (Z. Y. Li) X. Q. Li & X. G. Xiang, comb. & stat. nov. Morphologically, the new species can be distinguished from H. subacaulis by its calyx 5‐sect from base, segments narrowly oblong‐lanceolate (versus calyx 5‐sect from base or 2‐lipped and adaxial lip 2‐lobed from below middle, segments ovate), peduncle glabrous (versus pubescent), and vermiform sclereids dispersed in leaf mesophyll (versus without sclereids).     

Identification of species and materia medica within Angelica L. (Umbelliferae) based on phylogeny inferred from DNA barcodes

DNA barcodes have been increasingly used in authentication of medicinal plants, while their wide application in materia medica is limited in their accuracy due to incomplete sampling of species and absence of identification for materia medica. In this study, 95 leaf accessions of 23 species (including one variety) and materia medica of three Pharmacopoeia‐recorded species of Angelica in China were collected to evaluate the effectiveness of four DNA barcodes (rbcL, matK, trnH‐psbA and ITS). Our results showed that ITS provided the best discriminatory power by resolving 17 species as monophyletic lineages without shared alleles and exhibited the largest barcoding gap among the four single barcodes. The phylogenetic analysis of ITS showed that Levisticum officinale and Angelica sinensis were sister taxa, which indicates that L. officinale should be considered as a species of Angelica. The combination of ITS + rbcL + matK + trnH‐psbA performed slight better discriminatory power than ITS, recovering 23 species without shared alleles and 19 species as monophyletic clades in ML tree. Authentication of materia medica using ITS revealed that the decoction pieces of A. sinensis and A. biserrata were partially adulterated with those of L. officinale, and the temperature around 80 °C processing A. dahurica decoction pieces obviously reduced the efficiency of PCR and sequencing. The examination of two cultivated varieties of A. dahurica from different localities indicated that the four DNA barcodes are inefficient for discriminating geographical authenticity of conspecific materia medica. This study provides an empirical paradigm in identification of medicinal plants and their materia medica using DNA barcodes.     

Notes on some plant-inhabiting fungi collected from the Nansei Islands (2)

In this paper, four fungi collected in Nansei Islands are reported. One is Strasseria garciniae, which must be transferred to the genus Phyllosticta. This fungus was collected in Okinawa Main Island and Iriomote Island. The other three fungi are newly added to the Japanese fungal flora. Phyllosticta ghaesembillae on Codiaeum variegatum and Cercospora asplenii on Asplenium antiquum were collected in Yoron Island. The last one, Coniella australiensis on Eucalyptus robusta was collected in Okinawa Main Island. Their morphology and symptoms on the host plant are described, with some mycological notes.     

Restudy and reassignment ofDentalium antiquum Goldfuss, 1841 (Middle Devonian)

Dentalium antiquum is one of two moderately well-known Devonian “scaphopods” in the German literature. Examination of the type material and a few specimens in other institutions indicates more individual variability than is to be expected in species of the molluscan class Scaphopoda. The species is transferred with question toColeolus Hall, a fossil presumed to be a calcareous “worm” tube.      

Exploring the reticulate evolution in the Asplenium pekinense complex and the A. varians complex (Aspleniaceae)

The Asplenium pekinense complex mainly comprises one diploid, A. sarelii Hook. (rare), one autotetraploid, A. pekinense Hance (best known and very common), and shares two allotetraploids, A. anogrammoides Christ (common but often misidentified) and A. altajense (Komarov) Grubov (rare and endemic) with the A. varians complex. The latter is further constituted by two diploids, A. tenuicaule Hayata (widespread) and A. semivarians Viane & Reichstein (rare), as well as other three tetraploids, A. kansuense Ching (barely known), A. varians Wallich ex Hooker & Greville (well‐known, relatively common, and morphologically variable), and A. kukkonenii Viane & Reichstein (rare and often misidentified). These two species complexes are notorious for their taxonomic difficulty based on general morphology, which is mainly caused by their history of reticulate evolution. Here, we collected most species within the two complexes, and obtained ploidy information by spore size measurement and flow cytometry investigation. Phylogenetic analyses using DNA markers representing maternally inherited chloroplast and biparentally inherited nuclear genomes helped to reconstruct the reticulate evolution history. The present results support previous hypotheses that A. sarelii is the ancestor of both A. pekinense and A. anogrammoides, as well as that A. tenuicaule is the common progenitor of A. anogrammoides, A. varians, and A. kukkonenii. We also unraveled the autotetraploid origin of A. kansuense from A. tenuicaule for the first time, and found that A. altajense shares essentially identical genomes with A. anogrammoides.     

Asplenium cornutissimum (Aspleniaceae), a new species from karst caves in Guangxi, China

Asplenium cornutissimum, a new species from Guangxi, southern China, is described, illustrated, and compared to three similar species: A. pulcherrimum, A. coenobiale, and A. tenuifolium. So far, the new species is known only from the limestone region in southern Guangxi, from 750–825 m. It grows exclusively in karst caves.     

A new species and a new combination of <Emphasis Type="Italic">Allium</Emphasis> sect. <Emphasis Type="Italic">Rhizirideum</Emphasis> (Alliaceae) from northeastern China and Korea

A new species, Allium pseudosenescens, belonging to sect. Rhizirideum (Alliaceae), is described from northeastern China. It is easily distinguished from A. senescens by the slender pedicels, pale pink perianths, narrower tepals and ovaries, yellowish anthers, and sometimes toothed subulate filaments. Also, A. senescens var. minus in sect. Rhizirideum is raised to the rank of species, as A. minus. This Korean endemic taxon is shown to be a biologically distinct species based on morphological and cytological characters. Taxonomic keys for the species of Allium sect. Rhizirideum in northeastern China and Korea are provided.     

An ultrastructural study of the mature spermatozoid of the fern Asplenium trichomanes L. subsp. trichomanes

 Asplenium trichomanes L. subsp. trichomanes spermatozoids are spirals of about five turns. Keels link the elements of the microtubular ribbon with the plates of the lamellar layer (LL) which are uninterrupted, parallel and curved with an inner angle of about 150°. Electron-opaque filaments connect the microtubules of the multilayered structure (MLS) and the osmiophilic crest, the LL and the MLS-associated mitochondrion and the latter and the plasmalemma. The nucleus occupies the 2.5–3 posterior turns and has an inner honeycomb-shaped chromatin mass and an outer highly condensed chromatin mass with randomly scattered electron-transparent areas. The basal bodies of the ca. 50 flagella are bounded by a reticulum of granular material which forms a plug inside their proximal region; the proximal region of the flagellum has a 9 + 0 pattern. The axoneme has a 9 + 2 pattern. Received: 15 January 1997 / Revision accepted: 1 April 1997