8,220 research outputs found
Revealing a cryptic fern distribution through DNA sequencing: Pityrogramma trifoliata in the Western Andes of Peru
No full textFern identification usually requires the use of mature sporophytes, since attempts to identify juveniles using morphological traits often provides unsatisfactory results. Here we examined young sporophytes found among boulders in a river basin of a xeric valley in central Peru. Attempts to identify these sporophytes first pointed to four different genera, two in Pteridaceae (Anogramma and Pityrogramma), and the others in Aspleniaceae (Asplenium) and Cystopteridaceae (Cystopteris). Here, we resolved this puzzle combining morphology and sequences of DNA (rbcL and trnG-R) that point to Pityrogramma trifoliata of Pteridaceae
NUCLEAR PARACRYSTALS IN THE FERN POLYSTICHUM SETIFERUM GAMETOPHYTE
No full textSingle nuclear paracrystals were observed in gametophyte cells of the fern Polystichum setiferum. They consist of proteins poor in basic aminoacids and have sharp-profiled, polyhedral shapes, with inner diameters up to 4.5 mu m. The substructure is a fine, very close-meshed reticulum resolvable at magnifications of 40,000x or more. The hypothesis that these paracrystals are storage bodies of unused nuclear proteins is discussed
Do fern gametophytes have the capacity for irradiance acclimation?
No full textFerns present two alternant generations: sporophyte and gametophyte. In the present work we address the question of whether fern gametophytes have the potential to acclimate to different irradiances as vascular plants do. We studied the gametophytes of three different fern species belonging to the Aspleniaceae family with different ecological requirements (Asplenium trichomanes, Asplenium scoloprendrium and Ceterach officinarum). Fern spores were germinated and the gametophytes cultivated under photon flux density (PFD) of 10, 50 or 100 μmol m-2 s-1. From the early stages of spore germination (the formation of the 5-celled germinal filament), photosynthetic apparatus acclimates showing the typical patterns of photochemical responses to high or low PFD. In agreement with the photochemical pattern of acclimation, higher contents of xanthophyll cycle pigments and α-tocopherol was observed in plants grown under high PFD. The α/β-carotene ratio, used as indicator of the acclimation of the photosynthetic apparatus, also sustained the initial hypothesis except for A. trichomanes. We conclude that fern gametophytes display a complete array of photosynthetic and photoprotective traits that allow an effective acclimation to PFD
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
[Letter from Lila Fern Martin to T. N. Carswell - April 10, 1962]
No full textA letter written to Mr. T. N. Carswell, Abilene, Texas, from Lila Fern Martin, City Secretary, City of Abilene, dated April 10, 1962. Martin expresses his appreciation and that of the City of Abilene for Carswell having served as Judge of Election Precinct No. 10 at the election on April 3, 1962. cc: Mayor C. R. Kinard, Mr. R. M. Tinstman, City Manager
Distribution, habitat preferences and population sizes of two threatened tree ferns, Cyathea cunninghamii and Cyathea x marcescens, in south-eastern Australia
No full textThe distribution, population sizes and habitat preferences of the rare tree ferns Cyathea cunninghamii Hook.f. (Slender Tree Fern) and F1 hybrid Cyathea x marcescens N.A.Wakef. (Skirted Tree Fern) in south-eastern Australia are described, together with the extension of the known distribution range of Cyathea cunninghamii from eastern Victoria into south-eastern New South Wales. Floristic and ecological data, encompassing most of the known habitat types, vegetation associations and population sizes, were collected across 120 locations. Additional information was sought from literature reviews, herbarium collections and field surveys of extant populations.
Cyathea cunninghamii is widespread, with the majority of populations occurring in Tasmania and Victoria, one population in south-eastern NSW and a disjunct population in south-eastern Queensland; Cyathea x marcescens is confined to south and eastern Victoria and south and north eastern Tasmania. Both taxa occur on King Island in Bass Strait. Both taxa have a near coastal distribution with most populations occurring in sub-coastal hinterland and escarpment forests with a median altitude of 288 m. Hierarchical cluster analysis of floristic data across the species’ geographic range identified six vegetation communities ranging from rainforest to damp sclerophyll forest. Their micro-habitat preferences were consistently identified as steeply incised gullies of minor headwater streams of coastal and sub-coastal ranges with a plentiful moisture regime and geomorphic protection from extreme stream flow events, flooding and bank scouring. Sporophyte recruitment was associated with exposed soil of stream banks and edges of constructed walking tracks.
Population sizes of both taxa are small with the majority of populations consisting of less than five adult individuals, with total populations of Cyathea cunninghamii and Cyathea x marcescens estimated at 919 and 221 mature individuals respectively.
Population extinctions in Victoria and Tasmania have primarily been associated with outlier populations in regions subject to agricultural land clearance, habitat modification and changes to fire regimes in crown forests. Nonanthropogenic mortality was associated with land slips, tree falls and stream bank scouring by flood water. Conservation of the hybrid Cyathea x marcescens necessitates the preservation of habitats where both Cyathea cunninghamii and Cyathea australis occur in close proximity to substrates suitable for spore germination. In future, molecular techniques may prove useful for field identification of juvenile stages, facilitating selection of progeny of Cyathea cunninghamii and Cyathea x marcescens for cultivation and re-introduction to sites of previous or possible future extinctions
Pecluma M. G. Price, Amer. Fern. J.
No full text48.32. Pecluma M.G.Price, Amer. Fern. J. 73: 109 (1983). T.: Pecluma pectinata (L.) M.G.Price (Polypodium pectiatum L.)Published as part of Christenhusz, Maarten J. M., Zhang, Xian-Chun & Schneider, Harald, 2011, A linear sequence of extant families and genera of lycophytes and ferns, pp. 7-54 in Phytotaxa 19 on page 53, DOI: 10.11646/phytotaxa.19.1.2, http://zenodo.org/record/489399
J. Paul and Fern M. Swickard portraits
No full textTwo separate studio portraits of formally-dressed owners of the Strand Theatre; handwritten atop each picure 'J. Paul Swickard' (left) and 'Fern M. Swickard' (right), circa 1930s
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
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