No abstract

Eighteen species belonging to the Carex genus were checked for the presence and the amount of eight phenolic acids (p-hydroxybenzoic, vanillic, caffeic, syringic, protocatechuic, p-coumaric, sinapic, and ferulic) by means of HPLC. Both the free and bonded phenolic acids were analyzed. The majority of the analyzed acids occurred in the studied species in relatively high amounts. The highest concentrations found were caffeic acid and p-coumaric acid, for which the detected levels were negatively correlated. A very interesting feature was the occurrence of sinapic acid, a compound very rarely detected in plant tissues. Its distribution across the analyzed set of species can be hypothetically connected with the humidity of plants' habitats. Several attempted tests of aggregative cluster analysis showed no similarity to the real taxonomical structure of the genus Carex. Thus, the phenolic acids' composition cannot be considered as the major taxonomical feature for the genus Carex.

Abstract. We studied seasonal changes in the understorey biomass of an oak-hornbeam forest association Galio sylvatici-Carpinetum betuli. Samples were collected weekly during the most dynamic period of herbaceous layer development (April-May 2010), and every two weeks for the remainder of the growing season (June-October). Samples were collected from 10 randomly selected localities of 0.36 m 2 within the plant community. The plants harvested were separated by species, then oven-dried and weighed. There were statistically significant differences in aboveground understorey biomass during the time between harvests. For example, the lowest plant biomass (produced in 2010 and previous years) was found on April 3rd (37.2 kg/ha), whereas the two highest were on May 1 st (308.1 kg/ha) and June 12 th (337.6 kg/ha). The lowest biomass of plants produced in 2010 was on April 3 rd (13.0 kg/ha) and the highest was on May 1 st (259.8 kg/ha). When biomass of particular herbaceous plant species were analyzed, there was no one clearly dominant species. For example, from March 20 th to May 22 nd the biomass of Ficaria verna was the highest at ca. 36% of the total herbaceous layer plant biomass (range: 14.5-51.0%). During the next harvesting period (June-October), there were a few dominant herbaceous plant species, e.g. Geranium robertianum, Stachys sylvatica, Impatiens parviflora, Dryopteris dilatata, Dryopteris carthusiana, Dryopteris filix-mas, and Maianthemum bifolium.

Abstract. We studied seasonal changes in the understorey biomass of an oak-hornbeam forest association Stellario holosteae-Carpinetum betuli. Samples were collected weekly during the most active period of growth of the herbaceous layer (April-May 2010), and every two weeks for the remainder of the growing season (June-October). Quadrates of 0.36 m 2 were sampled from 7-9 randomly selected locations within the plant community. The plants harvested were separated by species, then oven-dried and weighed. We found statistically significant differences in aboveground understorey biomass over the periods of biomass harvesting. For example, the average plant biomass (produced in 2010 and previous years) was smallest on March 20 th (40.6 kg/ha), whereas the biomass was greatest on May 15 th (393.8 kg/ha). The mean biomass of the understorey vegetation during spring was 324.1 kg/ha, while the mean biomass for summer and early autumn was 108 kg/ha. The smallest plant biomass (produced during 2010) was on March 20 th (18.3 kg/ha) and the largest on May 15 th (378.4 kg/ha). Only a few herbaceous species dominated the total community biomass production. For example, from March 20 th to May 29 th the biomass of Anemone nemorosa was the highest at ca. 74% of total understorey herbaceous plant biomass, while Ficaria verna was second with 8%. During the next harvesting period (June-October) Galeobdolon luteum and Galium odoratum comprised 53.2% of total plant biomass harvested. It is evident that the highest biomass production is during the spring when the geophytes develop.

Plants growing in different kinds of habitats are expected to show high morphological plasticity. Carex spicata Huds. occurs in different plant communities and shows distinct morphological variability of the inflorescences. Field observations carried out in different plant communities permitted us to hypothesize that the morphological variability of C. spicata inflorescences may to some degree be the result of the habitat. The objective of this study was to test that hypothesis for C. spicata by collecting inflorescences and measuring their morphological features from several populations in each of six plant communities: Agropyro-Urticetum dioiceae, Arrhenatheretum elatioris, Lolio-Cynosuretum, Lolio-Plantaginetum, Trifolio-Agrimonietum, and Stellario-Deschampsietum. The following inflorescence features were analyzed: length of the lowest spikelet, distance between two lowest spikelets, length of inflorescence, number of spikelets, and length proportion of the lowest spikelet to the distance between the two lowest spikelets. We found that all analyzed morphological characters differed significantly among the plant communities. Furthermore, we found significant differences among populations within the six plant communities. Moreover, C. spicata inflorescences often have morphological features (i.e. a less crowded inflorescence with a relatively large distance between the two lowest spikelets) similar to the closely related species C. muricata L. Thus, the limited diagnostic value of inflorescence crowding, especially in vegetative or early fruiting phases, suggests that the taxonomic importance of this character should be reconsidered.