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1.
Relations between irradiance (I) and lichen growth were investigated for five macro‐lichens growing at two sites in Sweden. The lichens represented different mycobiont–photobiont associations, two morphologies (foliose, fruticose) and two life forms (epiphytic, terricolous). The lichens were transplanted at two geographically distant sites in Sweden (1000 km apart) from Sept 1995 to Sept 1996 in their typical microhabitats, where microclimate and growth were followed. Between April/May and Sept 96, the terricolous species had a dry matter gain of 0·2 to 0·4 g (g DW)–1 and the epiphytes 0·01 to 0·02 g (g DW)–1. When related to area, growth amounted to 30 to 70 g m?2 for the terricolous species and to 1 to 4 g m?2 for the epiphytes. There was a strong correlation between growth and intercepted irradiance when the lichens were wet (Iwet), with 0·2 to 1·1 g lichen dry matter being produced per MJ solar energy. Across the 10 sets of transplants, light use efficiencies of dry matter yield (e) ranged between 0·5 and 2%, using an energy equivalent of 17·5 kJ g?1 of lichen dry matter. The higher productivity of the terricolous species was due to longer periods with thallus water contents sufficient for metabolic activity and because of the higher mean photon flux densities of their microhabitat. A four‐fold difference in photosynthetic capacity among the species was also important. It is concluded that lichen dry matter gain was primarily related to net carbon gain during metabolically active periods, which was determined by light duration, photon flux density and photosynthetic capacity.  相似文献   

2.
Abstract:A new lichen species, Micarea viridileprosa, is described from western Europe, where it is locally very common. This species, which has previously been much overlooked, is corticolous, lignicolous and terricolous and is usually found sterile. Some specimens of the new species were formerly included in Micarea prasina. The new combination Micarea levicula (Nyl.) Coppins is made for Lecidea levicula Nyl. from Cuba.  相似文献   

3.
Phylogenetic relationships between Nostoc cyanobionts in the lichen genus Pannaria were studied to evaluate their correlation to geography, habitat ecology, and other patterns previously reported. The 16S rRNA gene sequences of a total of 37 samples of 21 Pannaria species from seven countries from the Northern and Southern hemispheres were analyzed and compared with 69 free‐living and symbiotic cyanobacterial strains. The sequences from Pannaria were distributed throughout a branch of Nostoc sequences previously called “the Nephroma guild,” and within two subgroups from another branch, referred to as the “Peltigera guild,” although there was a gradual transition between the two major groups. There is a more diverse pattern of relationships between Nostoc sequences from bipartite versus tripartite lichen species in Pannaria, compared with other well‐studied genera, such as Nephroma and Peltigera. Cyanobionts from several tripartite Pannaria species from the Southern Hemisphere and corticolous bipartite species from both hemispheres were grouped together. Four sequences of Pannaria and Pseudocyphellaria cyanobionts from rocks in the Chilean Juan Fernández Islands were nested within corticolous cyanobionts, whereas the terricolous “Pannaria sphinctrina clade” was placed with other terricolous strains. The cluster patterns derived from phylogenetic analysis were partly reflecting lichen taxonomy, in two groups of lichen species, possibly indicating coevolution. The phylogram partly also reflected lichen ecology. Three Pannaria species have very different cyanobiont strains when they grow in different habitats.  相似文献   

4.
Diploschistes hensseniae Lumbsch & Elix is described as new to science. It is characterized by its terricolous habitat, perithecioid closed ascomata, relatively small spores, cylindrical asci, and the presence of diploschistesic and orsellinic acids in addition to lecanoric acid. It occurs on soil in arid regions of Australia.  相似文献   

5.
根据对新疆博格达山地面生地衣群落27个样点(20 m×20 m)调查的数据,以各地衣种的盖度为指标结合双向指示种分析方法(TWINSPAN)和除趋势对应分析法(DCA)对博格达山地面生地衣群落进行数量分类并分析了群落结构特征及其多样性和相似性。采用典范对应分析法(CCA)对各群落的物种分布格局与环境因子的关系进行了探讨。结果表明,TWINSPAN分析和DCA排序将分布在博格达山的37种地面生地衣分为以下5个群丛。群丛1:膜地卷(Peltigera membranacea)+伴藓大孢蜈蚣衣(Physconia muscigena)群丛;群丛2:地卷(Peltigera rufescens)+伴藓大孢蜈蚣衣(Physconia muscigena)群丛;群丛3:裂边地卷(Peltigera degenii)+平盘软地卷(Peltigera elisabethae)群丛;群丛4:喇叭石蕊(Cladonia pyxidata)+犬地卷(Peltigera canina)群丛;群丛5:盾鳞衣(Placidium squamulosum)+缠结茸枝衣(Seirophora contortuplicata)群丛。物种多样性以群丛4最大为3.427;群丛1最小为0.672;群丛1和群丛4间的相似性最高为0.889,群丛3和群丛4相似性系数最低为0.607。CCA排序结果反映,该地区地面生地衣的分布受到森林植被郁闭度、人为干扰、光照强度的影响,而地表植被盖度和土壤pH等因素的影响不大。  相似文献   

6.
A new species Plantago pyrophila Villarroel & J. R. I. Wood is described from the Serranias de Santiago de Chiquitos in the cerrados of eastern Bolivia. It is clearly adapted to survival in the cerrado environment where grassland fires are a frequent event. The new species is remarkable for being geographically isolated from other species of the genus, being the only species of Plantago known from the cerrado biome.  相似文献   

7.
As a result of ongoing studies of the Rubiaceae of Gabon, the new species Colletoecema gabonensis is here described and illustrated. It is endemic to Gabon, where it is the only species of the genus, and is so far only known from three collections from the Ogooué-Lolo and Ngounié provinces. The new species is morphologically intermediate between its two congeners, C. dewevrei (from Cameroon, Central African Republic, Republic of the Congo, DR Congo, and Angola) and C. magna (endemic to Cameroon). The new species agrees with C. dewevrei in having flowers with exserted anthers and style, but differs in its sessile flowers and fruits. In the latter characters, it resembles C. magna, from which it can be separated by its smaller fruits and leaves, and by its different floral morphology. An IUCN conservation assessment has been made and the species is provisionally assessed as Vulnerable, based on its restricted area of occupancy and the small number of known locations.  相似文献   

8.
Annual, long‐term inundation of flood waters for 5–7 months has led to the development of survival strategies in terrestrial invertebrates of Central Amazonian floodplains. Strategies observed are given for terricolous and arboricolous species and include migrants and non‐migrants. Subadult and advanced juvenile stages of the symphylan Ribauliella amazonica Scheller pass inundation in a dormant state inside tree roots in the flooded soil. Reproduction in this univoltine species is restricted to the non‐inundation period. R. amazonica represents the terricolous non‐migrating invertebrate guild with dormant stages in naturally available retreats under water during annual inundation. The undescribed parthenogenetic centipede Lamyctes sp. is found to hatch from flood‐resistant eggs at the beginning of non‐inundation periods. Development is fast, with the first hemi‐edaphic post‐larvae being captured 6–8 weeks after the floods have receded. Their surface structure does not protect the strongly elevated stigmata from lethal inundation. Lamyctes sp. represents the terricolous non‐migrating invertebrate guild, with dormant egg stages under water during annual inundation.  相似文献   

9.
Summary   Linaria khalkhalensis Hamdi & Assadi is described as a new species from Azerbaijan and Guilan provinces (northern Iran), belonging to Linaria sect. Linaria. It is close to Linaria lineolata Boiss. and L. elymaitica (Boiss.) Kuprian., which it resembles in habit and vegetative features. However, floral and seed characters together with a distinctive geographical distribution, warrant recognition at the species rank. An illustration of the new species, a distribution map, scanning electron micrographs of seed and capsule surfaces, and an identification key are also included.  相似文献   

10.
Badiera subrhombifolia is newly described from Hispaniola, where it co-occurs with B. fuertesii and B. penaea. Badiera subrhombifolia lacks the long peduncle of the former species and the scabrous leaves of the latter; it is also often distinguishable by subrhomboid, triplinerved leaves. This new species is a near endemic to high montane forests of the “south island” of Hispaniola, i.e., the Massif de la Hotte, Massif de la Selle, and Sierra de Bahoruco.  相似文献   

11.
The recently described, terricolous and corticolous, sorediate lichen Lecanora flavoleprosa (belonging to the L. symmicta group) is for the first time recorded from the Carpathians. So far, this rare European species has only been reported from a few localities in the Austrian and Swiss Alps, and Fennoscandia (Norway and Sweden). In this paper several records from the Polish and Slovak Tatra Mts are presented, most of them found recently, but a few also discovered during revision of old material collected by Z. Tobolewski. The ecology and chemistry of the taxon, and differences from related sorediate Lecanora species are briefly discussed.  相似文献   

12.
Dacryodes uruts-kunchae is described, illustrated, and contrasted with D. steyermarkii. It is from white-sand plateaus and slopes of the sub-Andean cordilleras east of the Eastern Cordillera of the Andes in Ecuador, and from eastern foothills of the Andes in Peru. The new species is unusual for a number of reasons: (1) relatively few Burseraceae are found in tropical pre-montane and montane habitats; (2) it is dominant where it occurs, a rare phenomenon for Neotropical Dacryodes; (3) its staminate flowers show three stages in the transition from disk+pistillode to “ovariodisk”; and (4) it has relatively small, densely glandular-punctate, sclerophyllous leaflets.  相似文献   

13.
When two species are incompletely isolated, strengthening premating isolation barriers in response to the production of low fitness hybrids may complete the speciation process. Here, we use the sister species Drosophila subquinaria and Drosophila recens to study the conditions under which this reinforcement of species boundaries occurs in natural populations. We first extend the region of known sympatry between these species, and then we conduct a fine‐scale geographic survey of mate discrimination coupled with estimates of gene flow within and admixture between species. Within D. subquinaria, reinforcement is extremely effective: we find variation in mate discrimination both against D. recens males and against conspecific allopatric males on the scale of a few kilometres and in the face of gene flow both from conspecific populations and introgression from D. recens. In D. recens, we do not find evidence for increased mate discrimination in sympatry, even where D. recens is rare, consistent with substantial gene flow throughout the species’ range. Finally, we find that introgression between species is asymmetric, with more from D. recens into D. subquinaria than vice versa. Within each species, admixture is highest in the geographic region where it is rare relative to the other species, suggesting that when hybrids are produced they are of low fitness. In sum, reinforcement within D. subquinaria is effective at maintaining species boundaries, but even when reinforcing selection is strong it may not always result in a pattern of strong reproductive character displacement due to variation in the frequency of hybridization and gene flow from neighbouring populations.  相似文献   

14.
Summary  A new species of Dioscorea from Morondava prefecture in Western Madagascar is described. Dioscorea bako Wilkin differs from D. alatipes Burkill & H. Perr. by its usually shallowly and irregularly lobed leaf margins, broader leaf blade (grey-green below), longer petiole and the broadly cuneate area where the petiole is inserted onto the leaf blade in the basal sinus. It is pubescent, especially densely on young shoots and inflorescences. It is endemic to Morondava Préfecture and is endangered under IUCN Red List category criteria (IUCN 2001). The unusual morphological features of its inflorescences, some of which are shared with D. alatipes are discussed. Dioscorea bako is a favoured food source for people of the Menabe region and is reported by them to be increasingly hard to find. Immediate conservation measures are necessary to ensure that it remains extant and, in the medium to long term, research should be undertaken to guide its sustainable utilisation.  相似文献   

15.
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17.
The pollination of one plant species can be facilitated by the presence of one or more neighboring plant species and evidence has been found in some rewardless species of orchid that benefit from the presence of rewarding plant species in the neighborhood. There are two pollination mechanisms by which a non-rewarding orchid attracts pollinators and increases its reproductive success: (1) A magnetic species effect that occurs even though the flowers do not resemble those of the other species, and (2) floral mimicry where the mimic’s flower resembles that of the model plant species. Oncidium cosymbephorum is a Mexican rewardless epiphytic orchid whose flowers look like those of the rewarding shrub Malpighia glabra (Malpighiaceae). The resemblance of O. cosymbephorum to the oil-offering flowers of M. glabra attracts the same pollinators, and the fitness of the orchid is higher when M. glabra is present than when it is absent. We evaluated the facilitation by M. glabra of the orchid’s pollination for natural and artificial clumps of O. cosymbephorum close to and far from M. glabra over 4 years. Two experiments were performed at five different study sites to evaluate the effect of the presence and absence of M. glabra on the reproductive success of O. cosymbephorum. In experiment 1, we recorded fruit set production in natural and artificial monospecific clumps of the orchid, and in natural and artificial heterospecific clumps of O. cosymbephorum and M. glabra. In experiment 2, we recorded the fruit set of O. cosymbephorum at different sites where individuals grow in monospecific clumps, both before and after cultivated individuals of oil-producing M. glabra had been planted in their vicinity. Both experiments showed that the reproductive success of O. cosymbephorum was greater in the presence of M. glabra than it was in its absence. This study provides experimental evidence for the magnetic species effect. Floral similarity between O. cosymbephorum and M. glabra, should be experimentally tested to determine whether it is adaptive.  相似文献   

18.
Cortinarius breviradicatus sp. nov., found in deciduous forests, is described and illustrated from Niigata, Japan. It is characterized by its medium-sized to large dark brown basidiocarp, acutely conical pileus, and rooting stipe, and by subglobose to broadly ellipsoid basidiospores. In addition, the extracting solution from its basidiocarps exhibits a strong fluorescence around 400–430 nm in ultraviolet radiation (250 nm), which was observed in a species of Cortinarius sect. Orellani. The new species belongs to the section Orellani. The differences between the new taxon and similar species are briefly discussed.  相似文献   

19.
We describe a unique microsporidian species that infects the green stink bug, Chinavia hilaris; the brown marmorated stink bug, Halyomorpha halys; the brown stink bug, Euschistus servus; and the dusky stink bug, Euschistus tristigmus. All life stages are unikaryotic, but analysis of the consensus small subunit region of the ribosomal gene places this microsporidium in the genus Nosema, which historically has been characterized by diplokaryotic life stages. It is also characterized by having the reversed arrangement of the ribosomal gene (LSU –ITS‐ SSU) found in species within the “true Nosema” clade. This microsporidium is apparently Holarctic in distribution. It is present in H. halys both where it is native in Asia and where it is invasive in North America, as well as in samples of North American native C. hilaris collected prior to the introduction of H. halys from Asia. Prevalence in H. halys from mid‐Atlantic, North America in 2015–2016 ranged from 0.0% to 28.3%, while prevalence in C. hilaris collected in Illinois in 1970–1972 ranged from 14.3% to 58.8%. Oral infectivity and pathogenicity were confirmed in H. halys and C. hilaris. Morphological, ultrastructural, and ecological features of the microsporidium, together with a molecular phylogeny, establish a new species named Nosema maddoxi sp. nov.  相似文献   

20.
Plasmopara viticola is the causal agent of grapevine downy mildew and is among the most important diseases in viticulture. It originates from North America, where it coevolved with wild Vitis species. Beginning in the 1870s it turned into a global epidemic that has been causing severe yield losses. It is generally believed that a single species is causing downy mildew on a large variety of economically important cultivars. Here we report, based on one nuclear and two mitochondrial markers, that isolates from vineyards in the United States fall into three highly distinct phylogenetic lineages. One of these contains European strains and affects Vitis vinifera cultivars, while the other two lineages affect also other species of Vitis. The divergence between these lineages is high, and, judging from the genetic variation in other Plasmopara lineages, might reflect distinct species. Due to the potentially significant implications for quarantine regulations and resistance breeding, detailed studies will be necessary to clarify whether these genetically distinct lineages occur outside of North America or are still confined there.  相似文献   

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