192 research outputs found
Recent Developments to Improve the Numerical Accuracy
No full textGreen Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Numerical Analysi
Polystichum duyunense (subg. Haplopolystichum; Dryopteridaceae), a new cave fern from Guizhou, China
No full textA new cave fern of Polystichum (subg. Haplopolystichum; Dryopteridaceae), P. duyunense, is described from a limestone cave in southern Guizhou, China. Polystichum duyunense is most similar to P. cavernicola in having oblong pinnae, but the former has pinnae larger, often angled basiscopically, and somewhat imbricate, while the latter has pinnae smaller, angled acroscopically, and apart from each other
Polystichum loratum (Dryopteridaceae), a New Fern Species from Guizhou, China
No full textA new fern species, Polystichum loratum H. He & Li Bing Zhang (Dryopteridaceae), is described and illustrated from limestone cliffs in northern Guizhou Province, China. Polystichum loratum is most similar to P. yaanense Liang Zhang & Li Bing Zhang in having narrowly ovate to lanceolate abaxial rachis scales. The new species is distinguished by its lorate leaf lamina, the oblong to narrowly ovate microscales (broad-type) on abaxial pinna surfaces, and the exindusiate soli, while P. yaanense has lanceolate leaf lamina, subulate microscales (narrow-type) on abaxial pinnae, and indusiate son. Polystichum loratum is considered to be Critically Endangered (CR), based on IUCN Red List criteria
Polystichum clarinervium (subg. Haplopolystichum; Dryopteridaceae), a new fern from Emei shan, China
No full textA new fern species, Polystichum clarinervium, a member of P. subg. Haplopolystichum (Dryopteridaceae), is described and illustrated from Emei shan, Sichuan Province, Southwest China. The new species is similar to P. deltodon, but the former has pinnae slightly imbricate, pinna apex rounded, and veins clear, while the latter has pinnae not imbricate, pinna apex acute, and veins obscured. Polystichum clarinervium was found on a limestone slope under sparse forest at an elevation of 1300 m and is currently known from two small populations. It is classified as Critically Endangered (CR) following IUCN Red List criteria
Polystichum tiandengense (subg. Haplopolystichum; Dryopieridaceae), a New Cave Fern from Guangxi, China
No full textA new fern species, Polystichum tiandengense H. He & Li Bing Zhang (Dryopteridaceae), is described and illustrated from a limestone cave in the Guangxi Zhuangzu Autonomous Region, South China. Polystichum tiandengense is most similar to P. cavernicola. Li Bing Zhang & H. lie in having oblong to square pinnae with undulate margins, but the new species is distinguished by its pinnae mostly adjacent to each other or imbricating, and mostly sterile (vs. distant from each other and mostly fertile in P. cavernicola). Polystichum tiandengense is considered to be Critically Endangered (CR), based on RICN Red List criteria
Polystichum hubeiense (Dryopteridaceae), a new fern species from Hubei, China
No full textZhang, L., Zhu, Z. M., Gao, X. F. & Zhang, L. B. 2013: Polystichum hubeiense (Dryopteridaceae), a new fern species from Hubei, China. - Ann. Sot. Fennici 50: 107-110. A new fern species, Polystichum hubeiense Liang Zhang & Li Bing Zhang (Dryopteridaceae), is described and illustrated from limestone cliffs in western Hubei Province, China. Polystichum hubeiense is most similar to P. lanceolatum in having relatively small leaves and pinnae and similar pairs of pinnae per lamina. The new species is distinguished by having overlapping and papery pinnae that are dull adaxially and repand on the margin, while P. lanceolatum has contiguous and leathery pinnae that are lustrous adaxially and dentate and with hard spines on the margin
Pteris langsonensis (Pteridaceae), a new brake fern species from Lang Son Province, northern Vietnam
No full textA new fern species, Pteris langsonensis belonging to the P. cadieri complex (Pteridaceae), is described and illustrated from Lang Son Province, northern Vietnam. P. langsonensis is most similar to P. plumbea, but the former has typical dimorphic leaves and fertile pinnae much contracted and with a width of no more than half of sterile pinnae, while the latter has slightly dimorphic leaves. The new species is also similar to P. cretica, but the former has smaller habit and slightly toothed sterile leaf margins
Polystichum perpusillum (sect. Haplopolystichum, Dryopteridaceae), a new fern species from Guizhou, China
No full textPolystichum perpusillum L.B. Zhang & H. He, a new fern species of Polystichum sect. Haplopolystichum (Dryopteridaceae), is described and illustrated from the entrance to a karst cave in southern Guizhou, China. A phylogenetic analysis based on the chloroplast trnL-F sequences shows that it is phylogenetically isolated in the section with no close relatives. Morphologically, it is similar to P. minutissimum, but P. perpusillum has an acute lamina apex, up to 12 pairs of pinnae per lamina, and deltoid-ovate or ovate-lanceolate rachis scales, while P. minutissimum has a round lamina apex, 5-8 pairs of pinnae per lamina, and subulate or linear rachis scales. Polystichum perpusillum has a granulate sculpture with verrucae on its perispore, a sculpture rare in the genus. The species is considered to be critically endangered
Polystichum hainanicola (Dryopteridaceae), a new fern species from Hainan Island, China
No full textA new fern species, Polystichum hainanicola belonging to section Haplopolystichum (Dryopteridaceae), is described and illustrated from Hainan, the southernmost province of China. Polystichum hainanicola is most similar to P. guangxiense, but the former has pinnae with a length to width ratio of 2.5-2.7, lamina completely fertile and sori fewer than four above midrib of middle pinnae. In contrast, the latter has pinnae with a length to width ratio of ca. 3:1, lamina sterile in its lower portion and sori 6-11 above midrib of middle pinnae
Using a multilocus phylogeny to test morphology-based classifications of Polystichum (Dryopteridaceae), one of the largest fern genera
No full textBackground: Polystichum (Dryopteridaceae) is probably the third largest fern genus in the world and contains ca. 500 species. Species of Polystichum occur on all continents except Antarctica, but its highest diversity is found in East Asia, especially Southwest China and adjacent regions. Previous studies typically had sparse taxon sampling and used limited DNA sequence data. Consequently, the majority of morphological hypotheses/classifications have never been tested using molecular data. Results: In this study, DNA sequences of five plastid loci of 177 accessions representing ca. 140 species of Polystichum and 13 species of the closely related genera were used to infer a phylogeny using maximum likelihood, Bayesian inference, and maximum parsimony. Our analyses show that (1) Polystichum is monophyletic, this being supported by not only molecular data but also morphological features and distribution information; (2) Polystichum is resolved into two strongly supported monophyletic clades, corresponding to the two subgenera, P. subg. Polystichum and P. subg. Haplopolystichum; (3) Accessions of P. subg. Polystichum are resolved into three major clades: clade K (P. sect. Xiphophyllum), clade L (P. sect. Polystichum), and the HYMASO superclade dominated by accessions of P. sect. Hypopeltis, P. sect. Macropolystichum, and P. sect. Sorolepidium, while those of P. subg. Haplopolystichum are resolved into eight major clades; and (4) The monophyly of the Afra clade (weakly supported), the Australasian clade (weakly supported), and the North American clade (strongly supported) is confirmed. Conclusions: Of the 23 sections of Polystichum recognized in a recent classification of the genus, four (P. sect. Hypopeltis, P. sect. Neopolystichum, P. sect. Sorolepidium, P. sect. Sphaenopolystichum) are resolved as non-monophyletic, 16 are recovered as monophyletic, and three are monospecific. Of the 16 monophyletic sections, two (P. sect. Adenolepia, P. sect. Cyrtogonellum) are weakly supported and 14 are strongly supported as monophyletic. The relationships of 11 sections (five in P. subg. Haplopolystichum; six in P. subg. Polystichum) are well resolved
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