Observations on some Crysophyceae from North Wales

An examination by means of electron microscopy of phytoplankton samples from 23 localities in North Wales and Anglesey yielded 14 species of Synuraceae. Eleven of these have not been recorded previously from this region, and two species are new to Britain, viz. Mallomonas pugio Bradley and Spiniferomonas trioralis Takahashi.     

Observations on Thorea ramosissimaBory (Batrachospermales,Thoreaceae), a freshwater red alga rarely recorded in the British Isles

The conspicuous macroscopic stage of the freshwater red alga Thorea ramosissima has been re-discovered in the River Thames after a lapse of almost 140 years. In the 1840s it was reported only from Walton-on-Thames, but is now known from 13 localities along a 133 km stretch between Oxford and Teddington. It is transient, often remaining undetected at known localities in subsequent years. All British records are assessed, especially 19th century collections from the Thames. The ecology and the morphology of the macroscopic stage are discussed.     

基于rbcL和matK序列探讨马鞭草科部分植物的系统学位置

为探究适用于马鞭草科植物的DNA条形码及该类群的系统分类关系,对豆腐柴(Premna microphylla)的叶绿体基因ycf6-psbM、trnV-atpE、rbcL、trnL-F、psbM-trnD、atpB-rbcL、trnC-ycf6、trnH-psbA、rpl36-infA-rps8和核基因ITS序列进行了PCR扩增和测序,结果表明仅rbcL、trnl-F、trnH-psbA序列的PCR扩增以及测序效果较好,而ITS不能得到明显的扩增条带,ycf6-psbM不能成功测序,其它序列存在有部分双峰或噪值高等问题。根据DNA条形码标准,rbcL序列是所有测试条码中相对最适合的。应用rbcL和matK序列对马鞭草科(Verbenaceae)豆腐柴属、牡荆属(Vitex L.)、马鞭草属(Verbena L.)和大青属(Clerodendrum L.)等4属与唇形科宝盖草属(Lamium L.)、水苏属(Stachys L.)、鼠尾草属(Salvia L.)和香科科属(Teucrium L.)等4属的分类和系统发育关系进行分析,以紫草科Lithospermum multiflorum L.为外群,最大简约法对2个片段的单独和联合矩阵分别构建系统发育树。豆腐柴属和大青属应从马鞭草科划入唇形科,马鞭草属仍归于马鞭草科,而牡荆属的系统学位置还需更多的证据。     

A molecular assessment of species diversity and generic boundaries in the red algal tribes Polysiphonieae and Streblocladieae (Rhodomelaceae,Rhodophyta) in Canada

Sequence data generated during a Canadian barcode survey (COI-5P) of the tribes Polysiphonieae and Streblocladieae, a large and taxonomically challenging group of red algae, revealed significant taxonomic confusion and hidden species diversity. Polysiphonia pacifica Hollenberg, P. paniculata Montagne, P. stricta (Dillwyn) Greville and Vertebrata fucoides (Hudson) Kuntze were all complexes of two or more genetically distinct yet overlooked species. One variety of P. pacifica was elevated to the rank of species as P. determinata (Hollenberg) Savoie & Saunders, stat. nov. Several new additions to the Canadian flora were recorded including P. kapraunii Stuercke & Freshwater and P. morrowii Harvey. Subsequent multi-gene (COI-5P, LSU and rbcL) phylogenetic analyses confirmed that the genus Polysiphonia Greville was polyphyletic, and currently assigned species resolved with many other genera. Polysiphonia sensu stricto was restricted to a group of species that formed a monophyletic lineage with the type, Polysiphonia stricta. Carradoriella P.C.Silva was resurrected based on the South African species Carradoriella virgata (C.Agardh) P.C.Silva. Species previously attributed to Polysiphonia were transferred to Carradoriella, Leptosiphonia and Vertebrata as well as to three new genera described here: Acanthosiphonia gen. nov., based on A. echinata (Harvey) comb. nov.; Eutrichosiphonia gen. nov. for E. confusa (Hollenberg) comb. nov. and E. sabulosia (B.Kim & M.S.Kim) comb. nov.; and Kapraunia gen. nov., which includes K. schneideri (Stuercke & Freshwater) comb. nov. and three additional species.     

Species delimitation methods reveal cryptic diversity in the Hypnea cornuta complex (Cystocloniaceae,Rhodophyta)

The simple and convergent morphologies of many red algae make these species difficult to identify using traditional morphological characters. Many cryptic species have been described in recent years based on molecular datasets, and this has led to the application of an integrative taxonomy approach in species delimitation. Here, we performed several species delimitation methods (mBGD, ABGD, SPN, PTP, GMYCs and GMYCm) based on two different loci (COI-5P and rbcL) in species of the Hypnea cornuta complex. These methods were combined with morphological and phylogenetic data, extensive sampling, analysis of topotype material, and historically relevant herbarium samples. Our findings demonstrate that the groups morphologically assigned to H. cornuta and H. stellulifera consist of five different cryptic species. H. cornuta is a polyphyletic taxon composed of three well-separated lineages, thus requiring sequencing of type or topotype specimens to determine which one is Hypnea cornuta sensu stricto. We have revealed that the distribution of H. stellulifera is limited to Asia, while the Brazilian specimens initially assigned to this species were clarified as a new endemic species: Hypnea cryptica sp. nov. Our results indicated that only an integrative approach combining several lines of evidence, including morphology, nomenclature history, molecular data, biogeography and ecology can correctly solve the taxonomic status of widely distributed cryptic species.     

Chemical and genetic differentiation of Ligularia tsangchanensis in Yunnan and Sichuan provinces of China

The intraspecific diversity in L. tsangchanensis collected in the Chinese Provinces Yunnan and southwestern Sichuan was studied by chemical and genetic approaches. The samples collected in Yunnan were found to contain cacalol (1) as the sole major component, while samples from Sichuan contained 7alpha- and 7beta-eremophila-9,11-dien-8-one (5 and 6) as well as the 3alpha-angeloyloxy derivative 7 as major components. In addition, the sequences of the internal transcribed spacers (ITSs) of the ribosomal RNA gene indicated that the Yunnan and the Sichuan samples constitute separate clades. These results demonstrate that L. tsangchanensis in Yunnan and Sichuan are distinct.     

Chemical and genetic diversity of Ligularia latihastata and Ligularia villosa in Yunnan Province of China

The chemical constituents of the root extracts and the nucleotide sequences of the atpB-rbcL intergenic region of Ligularia latihastata and L. villosa, collected in northwestern Yunnan Province, were studied. In the twelve collected samples of L. latihastata, two major benzofurans, 5,6-dimethoxy-2-(1-methylethenyl)-1-benzofuran (1) and euparin (2) were detected as major components. The minor compound (2R*,3S*)-5-acetyl-2,3-dihydro-6-hydroxy-2-(1-methylethenyl)-1-benzofuran-3-yl (2Z)-2-[(acetoxy)methyl]but-2-enoate (4) was found to be susceptible to artifact formation upon extraction with EtOH. The intra-specific diversity in chemical composition of the samples was small, but the diversity in the atpB-rbcL sequence was fairly large. Compounds 1 and 2 were also found in the three collected samples of L. villosa, indicating that the two species are chemically close to each other, in agreement with morphological taxonomy.