نتایج جستجو برای: hieracium
تعداد نتایج: 222 فیلتر نتایج به سال:
Hieracium sinoaestivum Sennikov sp. nov. is described as new to science and illustrated. This presumably apomictic species is solely known from two old collections made in a single locality in the Shanxi Province of China. It belongs to the hybridogenous group Hieracium sect. Aestiva (Hieracium sect. Prenanthoidea × Hieracium sect. Umbellata) and is most similar to Hieracium veresczaginii from ...
A new species of hawkweed Hieracium maccoshiana T.C.G.Rich sp. nov. is described. It is related to the Norwegian Hieracium dovrense Fr., but differs in the shape and toothing of the stem leaves and in having glabrous-tipped ligules. It is endemic to the county of Sutherland, Scotland where it has been recorded from four sites. A lectotype of Hieracium dovrense is designated.
Hieracium, or hawkweed species, serious weeds in South Island high country, may be controlled by appropriate pastoral management. Experimental trials at Lake Tekapo, related to S and P fertiliser rates of 0-100 kg ha-l yr-l, 27 different combinations of over-drilled and resident species and different seasons or intensities of grazing treatments on Hieracium dominated fescue tussock were conduct...
Possible control options are investigated for the introduced Hieracium weeds, particular problems in South Island high country, New Zealand. In a pot experiment regression of input to output ratios of above ground biomass over successive harvests, from binary mixtures was used to determine the competitive interaction between 13 pasture species and two Hieracium species, H. pilosella and H. prae...
A technique for inferring long term time trends in vegetation from permanent quadrat data using the different patterns in the scattergram of the mean and rates of change of attributes, e.g., cover, from individual quadrats over short periods is described. The technique is illustrated using point intercept cover data for Hieracium species from permanent transects in the Waimakariri measured at i...
The LOSS OF APOMEIOSIS (LOA) locus is one of two dominant loci known to control apomixis in the eudicot Hieracium praealtum. LOA stimulates the differentiation of somatic aposporous initial cells after the initiation of meiosis in ovules. Aposporous initial cells undergo nuclear proliferation close to sexual megaspores, forming unreduced aposporous embryo sacs, and the sexual program ceases. LO...
We investigate the spread of an exotic herb, Hieracium lepidulum, into a New Zealand Nothofagus forest with the aim of understanding how stand-development of tree populations, propagule pressure and invader persistence, affect invasion across the landscape and within communities. Using data repeatedly collected over 35 years, from 250 locations, we parametrize continuous-time Markov chain model...
Species abundance, species richness, and ground cover were measured over 10 years on nine paired grazed and exclosure plots in short-tussock grassland in the early stages of invasion by Hieracium species. With and without grazing, H. pilosella and H. caespitosum increased markedly and H. lepidulum increased locally. In contrast, 50% of all other common species and species groups, and total, nat...
The year 2006 is the 140th anniversary of Mendel’s pathbreaking article. It is appropriate that a journal devoted to genetics begin the year with an article about Mendel and his work. Much has been written about his deep insights and the failure of the biological community to recognize his work. Here, on this anniversary, instead of extolling his success, we present a scholarly account of Mende...
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