Caldenal tvoří společenstva semiaridních lesů subtropického až mírného pásu střední Argentiny s dominantním druhem Prosopis caldenia. Od počátku 20. stol. byla značně exploatována kácením a využívána pro pastvu dobytka. Oheň, který zde byl přirozeným a nyní je i umělým činitelem, zásadně ovlivňuje obnovu caldenalu. Článek přináší základní údaje o tomto společenstvu a vlivu pastvy i ohně na jeho strukturu a biodiverzitu. and Caldenal is a semi-arid forest ecosystem in subtropical and temperate regions of Central Argentina, dominated by Prosopis caldenia. Since the beginning of the 20th century, Caldenal has been affected by wood harvesting and livestock grazing. Fires, both accidental and intentional, have played a key role in Caldenal regeneration. This paper describes the characteristics of these forests and addresses the effect of grazing and fire on their structure and biodiversity.
Morphological variation of Carex muricata from 232 localities in the Czech Republicwas analysed. The plants were preliminarily classified using qualitative characters into six species: C. contigua, C. muricata, C. pairae, C. chabertii, C. divulsa, and C. leersiana. Of 27 quantitative characters, all were used in a principal components analysis and 25 in a discriminant analysis. Both analyses were done using the data for all the species and then separately for the taxonomically complicated species pairs. In the discriminant analysis, the most useful characters for separating particular species were selected; they included the distance between the first and second lowermost spike of the infructescence, infructescence length, glume length in pistillate flower, achene length, length of perigynium beak and spike size. In the classification discriminant analysis, with the six most important characters, 94.4% of plants were correctly classified to the designated groups. The analysis showed that some species pairs (C. muricata – C. pairae, C. chabertii – C. leersiana) are only partially distinguished by quantitative morphological characters. Some other species (C. contigua, C. divulsa), however, are well differentiated and easily identified.
Chromosome numbers were determined for 97 samples of 95 sedge taxa (Carex) from the following countries: Austria (6 records), Bulgaria (1), the Canary Islands (Spain, 1), Cape Verde (1), the Czech Republic (51), Hungary (1), Italy (2), Norway (8), Russia (15), Slovakia (1), Sweden (1) and 9 North American plants cultivated in Czech botanical gardens. Chromosome numbers for Carex argunensis, C. callitrichos, C. campylorhina, C. flavocuspis subsp. krascheninnikovii, C. paniculata subsp. hansenii, C. pallida, C. quadriflora and C. xiphium are reported here for the first time. The first reports are presented for the European portion of the distribution area of Carex obtusata and for the Central European portion of the distributional areas of C. chordorrhiza, C. otrubae, C. rhizina and C. strigosa. New counts for the Czech Republic fill the gaps in the karyological data for this genus in relation to the Flora project in the Czech Republic.
The name Carex muricata subsp. lamprocarpa “Čelak.” (1879) is frequently used in floras for C. pairae F. W. Schultz when it is treated as a subspecies of C. muricata L. However, the combination C. muricata var. lamprocarpa was published by Wallroth in 1822. The corresponding specimen in Wallroth’s collection in PR, studied by L. Čelakovský and designated here as a lectotype, is C. muricata as it has the characteristic shiny utricles. So the combination C. muricata subsp. pairae (F. W. Schultz) Čelak. (1870) has to be used.