Search results for " charophytes"
showing 9 items of 9 documents
The role of herbaria for taxonomic and distributional studies in Characeae: examples from the Herbarium Mediterraneum Panormitanum (PAL) and the Flor…
2018
Characeae is a taxonomically critical family. Taxonomical uncertainties inevitably affect its distributional data. The role of herbarium specimens, particularly types and original material, is crucial for unravelling taxonomical ‘knots’. Moreover, wet areas have undergone dramatic reduction and modification in the last century and historical herbarium specimens may represent basic documents for the reconstruction of former distributions. Some preliminary data from two different Italian Herbaria are here presented. The Herbarium Mediterraneum Panormitanum (PAL, the standard acronym according to the Index herbariorum, http://sweetgum.nybg.org/ ih) houses four folders of Characeae exsiccata. T…
The role of Characeae in the communities of the vegetation class Potametea
2018
The stonewort vegetation is commonly classified into the phytosociological class Charetea fragilis F. Fukarek ex Krausch 1964; however, the Characeae are not exclusively found in vegetation stands ascribed to this class but also in other habitat types. In our preliminary investigations, we draw the attention to the relationship between the classes Charetea fragilis and Potametea pectinati Klika in Klika & Novák 1941 in some Sicilian biotopes. In some cases, the Charetea vegetation is ecologically and spatially distinct, although close, from that referable to the Potametea. In some other cases, one or more species of Characeae are structurally intrinsic to the vegetation of Potametea: on…
Pre-Linnaean illustrations as original material of Linnaean Chara names (Characeae)
2018
Wood (1960) investigated about the types of the four names of Characeae published by Linnaeus (1753) in his Species Plantarum. He focussed on the herbarium specimens forgetting the images mentioned in the protologues. Here we list and present the pre-Linnaean illustrations that have to be considered “original material” (according to the International Code of Nomenclature) for the mentioned names. Chara tomentosa L. - Wood (1960) defined the specimen 1088.1 in the herbarium LINN as “holotype”, actually it is a lectotype (as well reported in The Linnaean Plant Name Typification Project, http://www.nhm.ac.uk/ our-science/data/linnaean-typification) because of the two different figures cited in…
New records of Characeae for Sicily (Italy)
2018
During the last year, the first two authors continued their survey of the scarcely known Characeae flora of the island of Sicily: plants were collected in different periods, habitats and areas of the island, and identifications – made on fresh material – were based mainly on Mouronval et al. (2015). We had the opportunity to include here some results deriving from the visit in Sicily made by Klaus van de Weyer in March 2018. Roman Romanov identified some specimens and revised some identifications. Data for Sicily are basically limited to more than one hundred years old reports; data for the national Flora have been completed with recent reports for Sardinia (cf. the work made by Ralf Becker…
Food Sources for Benthic Grazers in Trophic Networks of Macrophyte Habitats in a Transitional Baltic Ecosystem
2022
In this study, we provide insights into that characteristics of two sites representing different conditions of productivity and salinity impact on trophic network structures of macrophyte habitats and diet of benthic grazers at the active vegetation period in the Curonian Lagoon (southeastern Baltic Sea). Regarding the epiphytic growth, macrophytes were more overgrown in the relatively less productive (northern) site with a muddy bottom and more frequent marine water inflow than in the (southern) site with higher productivity and freshwater sandy habitat. Stable isotope analysis revealed that organisms’ samples from the northern site were more enriched with the heavier carbon isotopes, but …
Charophytes for description and monitoring of inland waters in Sicily
2017
The island of Sicily, in the center of the Mediterranean basin, is a well-known biodiversity hotspot (Médail & Quézel, 1997). Unfortunately, the knowledge of its charophyte flora is absolutely unsatisfactory. The few available data derive from some scattered phytosociological works and some articles published more than 100 years ago. According to the last national synthesis (Bazzichelli & Abdelahad, 2009) a total of 19 Charophytes species should occur in the island, distributed in 4 genera: Chara L. (11), Nitella Agardh (5), Tolypella (A. Braun) A. Braun (2) and Lamprothamnium J. Groves (1). However an updated list of the species occurring in the island, together with their distribu…
Algunos aspectos de la variabilidad de los oogonios en poblaciones actuales del género <i>Chara</i> (Charophyceae). Aplicación paleontoló…
1986
A critical revision of some useful taxonomic criteria in paleontology of Charophytes is carried Out. The results are based in four modern populations ((<i>Chara aculeolata, Chara</i> aff.<i>baltica, Chara delicatula</i> and <i>Chara globularis</i>) and they permit to make some serious objections to these critera. The results are related with three principal aspects: the meaning of the absolute magnitudes of me girogonite, the behaviour of his joint variation and the morphological variability during the calcification process. In general, and for each one of the four populations, an absence of influence of the position of the girogonite over their measureme…