Ellesmeris sphenopteroides,gen. ET SP. NOV., a new zygopterid fern from the Upper Devonian (Frasnian) of Ellesmere,N.W.T., Arctic Canada

A new fern-like fossil plant is described from the lower Upper Devonian of southern Ellesmere Island, Canadian Arctic Archipelago. The plant occurs in an Archaeopteris-dominated flora preserved in the Nordstrand Point Formation (Mid-Late Frasnian) near Bird Fiord. The plant has a pinnate vegetative system with three branch orders and laminate sphenopteroid pinnules. Primary pinnae usually diverge from the main axis in distichous pairs (quadriseriate), but can depart singly (biseriate). Each primary pinna bears a basal catadromic aphlebia. Anatomically, the plant exhibits a mesarch, bipolar protostele that is ribbon- to clepsydropsoid-shaped in the main axis. Primary pinna traces are also initially bipolar and crescent-shaped, but may become four-ribbed before dividing into a pair of bipolar traces. The morphology and anatomy of this plant are nongymnospermous and are most similar to Zygopteridales (particularly Rhacophytaceae and Zygopteridaceae). The Frasnian age of Ellesmeris shows that laminated foliage had evolved in some zygopterid ferns much earlier than previously recognized. The Sphenopteris-like pinnules of Ellesmeris indicate the need for caution when attributing such a convergent foliar design to other plant groups, such as the Devonian gymnosperms.     

福建梅花山自然保护区蕨类植物区系研究

通过野外调查和资料整理,统计分析梅花山自然保护区蕨类植物区系组成和分布区类型,比较其与周边相邻4个自然保护区的蕨类植物区系的相似性。结果表明:(1)梅花山自然保护区共有蕨类植物42科83属189种,科、属组成优势现象明显,区系起源古老。(2)分布区类型在科、属级水平上以泛热带分布和世界分布为主,种级水平以热带亚洲分布、东亚分布和中国特有分布为主,热带亲缘明显,具有由热带向温带过渡的性质。(3)在地理亲缘关系上,梅花山与梁野山的蕨类植物区系联系最为紧密,与圭龙山的关系次之,与热带区系性质较强的南靖南亚热带雨林自然保护区和典型的中亚热带性质的武夷山自然保护区的种子植物区系联系较为疏远,具有从南亚热带向中亚热带过渡的明显特点。     

Species richness of sawfly–host plant associations at higher taxonomic levels

Insect–plant interactions are important to understanding the evolutionary mechanisms responsible for most of the diverse plant‐feeding insects. We aggregated data on sawfly–host plant associations and other resource associations from existing sources to address the following questions: (i) Is there a general correlation between host diversity and sawfly species richness? (ii) Is the pattern of host plant use consistent across sawfly lineages? and (iii) Is there a phylogenetically significant shift in species richness among sawflies? Our analysis comprised 8567 sawfly species, including 2087 species with host plant and other records. In total, there were 2126 records of host usage for sawflies, the overwhelming majority of which were sawflies using angiosperms as resources. Rosales are used by most of the species in sawfly families or subfamilies. We found that there was a strong correlation between the number of host plant orders and the species richness of sawfly families and subfamilies. To examine the points at which sawflies have experienced significant shifts in species richness, we compared sister taxon species richness. Several positive and negative shifts in species richness among sawflies were related to their range of host plant usage and specialized niche, respectively. In general, we found that most of the sawfly families and subfamilies used several orders as host plants, but mainly core eudicots, although some families or subfamilies were specialized on pteridophytes or gymnosperms.     

五种紫萁属植物的核型分析

研究了5种紫萁属Osmunda植物的核形态学特征, 其间期核属于复杂染色中心型, 有丝分裂前期染色体为中间型, 对有丝分裂前期染色体的动态变化过程和在细胞核内的自然排布情况进行了观察。核型公式为: 粗齿紫萁O. banksiifolia (Presl) Kuhn, 2n=4sm+10st+26t+4T; 紫萁O. japonica Thunb., 2n=2sm+8st+32t(2SAT)+2T;华南紫萁O. vachellii Hook., 2n=4sm+8st+28t+4T; 狭叶紫萁O. angustifolia Ching ex Ching &; Ch. H. Wang, 2n=2sm+4st+34t+4T; 粤紫萁O. mildei C. Chr., 2n=2sm+6st+33t+3T。所有染色体臂比均大于2, 核型类型均为4A, 后3种染色体为首次报道, 且对5种紫萁属植物的核型变异及演化关系进行了讨论, 推测Plenasium亚属3种紫萁属植物中粗齿紫萁核型类型最原始, 狭叶紫萁最进化, 其地理分布与核型不对称性有关联, 粤紫萁可能为一自然种间杂种。     

陕西天华山自然保护区蕨类植物区系研究

在调查天华山自然保护区植物组成的基础上,对该区的蕨类植物区系进行了分析。天华山自然保护区共有蕨类植物24科48属111种(包括种下类群),其区系的基本特征是:①种类丰富,种系密度大;②优势科明显,大部分科内属、种贫乏;③地理成分多样,区系联系广泛;④温带性质显著,与热带蕨类植物区系有一定的亲缘关系;⑤南北过渡性明显;⑥区系具有一定古老性;⑦特有化程度高,有51个中国特有种,以西南、华中和华北成分为主,并有1个中国特有属。另外,在中国特有种中有9个陕西(秦岭)特有种。     

Origin and taxonomic affinities of Thelypteris (subgen. Stegnogramma) burksiorum (Thelypteridaceae)

This paper examines the ecology, frond and spore morphology, gametophytes, and molecular biology ofThelypteris burksiorum to reveal its taxonomic affinities and phytogeographic origin. The species is endemic to Winston County in northern Alabama (U.S.A.) and only occurs in cave-like rockhouse habitats. A related species,T. pilosa, is widespread in central and southern Mexico, Guatemala, and Honduras.Thelypteris pilosa is extremely variable and our data suggest that current recognition of the varietiesmajor andpilosa is not warranted.Thelypteris pilosa is clearly closely related and likely sister toT. burksiorum. Thelypteris burksiorum exhibits the unusual production of gametophytic propagules. This, in combination with current levels of genetic diversity and reproductive biology, suggests thatT. burksiorum is an ancient Tertiary relict and not an example of recent long distance dispersal. Selection in rockhouse habitats has driven species away from their normal life cycle to partial or complete reliance on the gametophyte generation. The combination of a reduced yet fertile sporophyte and a gametophyte that may rely on gametophytic proliferation placesT. burksiorum in an intermediate evolutionary position relative to other rockhouse pteridophytes.     

安徽齐云山区蕨类植物区系研究

皖南齐云山区地处中亚热带,自然条件较为优越。蕨类植物丰富,初步统计显示,该山区共有蕨类植物29科,54属,91种9包括亚种和变种）,区系综合系数为-0.592。在相比较的7个山地区系中位居第五,通过对区系组成,性质和特征的分析。表明该区系地理成分复杂多样,属,种均可划分为12种类型（变型）,具有较强的亚热带特性;在区系关系上,该区系与黄山,九华山,天目山,庐山区系关系较为密切,而与武夷山,秦岭,长白山区系关系较为疏远。     

西藏林芝地区药用蕨类植物资源

本文对西藏林芝地区药用蕨类植物 39种 ,从产地、生境、海拔范围、性味、功效等作了初步分析     

广西蕨类植物新资料

报道了广西蕨类植物地理分布新记录 5个分类群。     

Mapping nutrient resorption efficiencies of subarctic cryptogams and seed plants onto the Tree of Life

Nutrient resorption from senescing photosynthetic organs is a powerful mechanism for conserving nitrogen (N) and phosphorus (P) in infertile environments. Evolution has resulted in enhanced differentiation of conducting tissues to facilitate transport of photosynthate to other plant parts, ultimately leading to phloem. Such tissues may also serve to translocate N and P to other plant parts upon their senescence. Therefore, we hypothesize that nutrient resorption efficiency (RE, % of nutrient pool exported) should correspond with the degree of specialization of these conducting tissues across the autotrophic branches of the Tree of Life. To test this hypothesis, we had to compare members of different plant clades and lichens within a climatic region, to minimize confounding effects of climatic drivers on nutrient resorption. Thus, we compared RE among wide‐ranging basal clades from the principally N‐limited subarctic region, employing a novel method to correct for mass loss during senescence. Even with the limited numbers of species available for certain clades in this region, we found some consistent patterns. Mosses, lichens, and lycophytes generally showed low RE_N (<20%), liverworts and conifers intermediate (40%) and monilophytes, eudicots, and monocots high (>70%). RE_P appeared higher in eudicots and liverworts than in mosses. Within mosses, taxa with more efficient conductance also showed higher RE_N. The differences in RE_N among clades broadly matched the degree of specialization of conducting tissues. This novel mapping of a physiological process onto the Tree of Life broadly supports the idea that the evolution of conducting tissues toward specialized phloem has aided land plants to optimize their internal nitrogen recycling. The generality of evolutionary lines in conducting tissues and nutrient resorption efficiency needs to be tested across different floras in different climatic regions with different levels of N versus P availability.