Search results for " grass"
showing 10 items of 145 documents
Short-term response of the slow growing seagrass Posidonia oceanica to simulated anchor impact
2007
Experimental evaluations about the impact of anchors of small vessels have previously shown that each anchoring can on average damage up to six shoots of Posidonia oceanica, removing small amount of biomass and, at the same time, interrupting continuity among shoots. The aim of the paper was to investigate the response of P. oceanica to different damage intensity at two levels of substrata compactness. Three treatments were considered: control (no damage); low damage (simulated anchor damage by three strokes of a hoe); and high damage (six strokes). Disturbance was higher where the substratum was highly penetrable and after one year significant variation was observed among treatments for bo…
Taxonomic and Phylogenetic Investigations on Psoralea Acaulis (Psoraleeae: Fabaceae) With the Description of A New Genus Kartalinia
2018
Salmeri, Cristina/0000-0002-5261-590X WOS: 000454161300003 Psoralea acaulis Hoffm. is a very peculiar and taxonomically isolated species of the tribe Psoraleeae, occurring in the Caucasian territories. Currently, this tribe contains 10 distinct genera, well differentiated morphologically. Due to some morphological similarities, P. acaulis was attributed to Bituminaria Heist ex Fabr., a genus with a Mediterranean-Macaronesian distribution. However, as it has many characters, some of which are autapomorphic, it was assigned its own subgenus: Christevenia Barneby ex C. H. Stirt. In light of detailed cladistic and phylogenetic analyses, this arrangement is taxonomically questionable and rather …
Taxonomic investigations on Psoralea palaestina (Fabaceae), a critical species of Mediterranean flora
2016
Psoralea palaestina is a critical and unappreciated species described from Palestinian territories, and currently treated as synonym of P. bituminosa, nowadays known as Bituminaria bituminosa. Nomenclatural investigations allowed to ascertain that it was validly described for the first time by Bassi (1768) and not by Gouan (1773), as previously thought. Extensive taxonomic investigations revealed that this very peculiar legume is morphologically well differentiated from the other allied known species. Therefore, it has to be properly treated at specific level and transferred to the genus Bituminaria, thus proposing a new combination: Bituminaria palaestina. Based on literature, herbarium an…
Seedling growth of a native ( Ampelodesmos mauritanicus ) and an exotic ( Pennisetum setaceum ) grass
2016
Scarce information is available on the biological reasons why a small subset of introduced species can effectively establish within novel ecosystems. A comparison of early growth traits can help to explain the better performance of alien invasive species versus native co-occurring species. In one year-long experiment, we compared the early life stages of Ampelodesmos mauritanicus (Poir.) Dur. & Schinz (Amp), a native perennial Mediterranean grass, and Pennisetum setaceum (Forssk.) Chiov (Penn), an emerging invader grass in sub-arid and Mediterranean-climate areas. The Penn seedlings grew significantly faster and were approximately 2.5 times taller than the Amp seedlings, reaching a fina…
Two new varieties in Stipa (Poaceae) from Central Asia
2016
Abstract The paper presents descriptions of two new taxa, Stipa ×brevicallosa var. hissarensis and Stipa orientalis var. ladakhorum. Both of them differ from the nominal varieties in having densely pubescent (not glabrous or scabrous) leaves of vegetative shoots. First of the above mentioned taxa occurs in Tajikistan (Pamir Alai Mts) whereas the second in India (Western Himalayas). Images of type specimens of both taxa are provided.
Scale- and taxon-dependent patterns of plant diversity in steppes of Khakassia, South Siberia (Russia)
2016
The drivers of plant richness at fine spatial scales in steppe ecosystems are still not sufficiently understood. Our main research questions were: (i) How rich in plant species are the natural steppes of Southern Siberia compared to natural and semi-natural grasslands in other regions of the Palaearctic? (ii) What are the main environmental drivers of the diversity patterns in these steppes? (iii) What are the diversity-environment relationships and do they vary between spatial scales and among different taxonomic groups? We sampled the steppe vegetation (vascular plants, bryophytes and lichens) in Khakassia (Russia) with 39 nested-plot series (0.0001-100-m(2) plot size) and 54 additional 1…
Defoliation-induced changes in carbon allocation and root soluble carbon concentration in field-grown Lolium perenne plants: do they affect carbon av…
2005
Summary 1It is hypothesized that defoliation-induced changes in plant carbon allocation and root soluble C concentration modify rhizosphere C availability and, further, the abundance and activity of soil microbes and their grazers. To test this hypothesis, field-grown Lolium perenne swards were defoliated twice during their second growing season at two nitrogen availabilities (added N or no added N). Plant, soil and microbial attributes were measured 2 and 4 days after the last defoliation, and nematode abundance was measured 6 days after the last defoliation. 2Defoliation decreased shoot production in plots where N was added, but had no significant effect in plots where N was not added. Ro…
Study of the growth of herbicide-resistant black-grass populations
1991
International audience
Stipa dickorei sp. nov. (Poaceae), three new records and a checklist of feather grasses of China
2016
Stipa dickorei sp. nov. from the Western Tibetan Plateau (China) is described. The new species is morphologically similar to S. regeliana, but they differ from each other in the length of ligules of vegetative shoots. Stipa dickorei is also similar to S. aliena, however they differ in the shape of panicle, which is contracted with straight branches in S. dickorei, and lax with flexuous branches in S. aliena. Images of macromorphological and micromorphological structures of the new taxon are provided. Additionally, new records of S. borysthenica, S. richteriana, and S. zalesskii, species not listed in the recent Flora of China, as well as a checklist of Chinese feather grasses are also prese…
Festuca valesiacaSchleich. ex Gaudin newly discovered in the Central Apennines (Italy): a further example of steppe relict in the Abruzzo “dry valley…
2019
Festuca valesiaca Schleich. ex Gaudin subsp. valesiaca is acknowledged as one of the most characteristic grasses of the continental grasslands and steppes of Eurasia. In Italy, the species was known almost only from the continental valleys of the Alpine chain (with the exception of two small populations at the northernmost edge of the Apennines). Here, we report on the first confirmed finding of F. valesiaca subsp. valesiaca in the surroundings of the Fucino Basin, Central Apennines. This finding expands by c. 400 km southwards the species’ range in Italy. The identity of the species was first ascertained by means of leaf cross-sections and stomata measurements, and then confirmed by chromo…