There are 20 endemic genera of mosses and three of liverworts in North America, north of Mexico. All are monotypic except Thelia, with three species. General ecology, reproduction, distribution and nomenclature are discussed for each genus. Distribution maps are provided. The Mexican as well as Neotropical genera of bryophytes are also noted without detailed discussion.
Following the opening of the Rhine-Main-Danube waterway in 1992 the invasive gobiid Proterorhinus marmoratus started colonizing the River Main and the River Rhine. In 2005, point abundance sampling revealed the presence of the species in two impoundments of the River Moselle next to the confluence with the River Rhine. This distribution pattern suggests that tubenose goby actively immigrated into the River Moselle by using locks and fishways. Highest population densities were recorded in lentic to slightly lotic habitats in headwater reaches of weirs as well as in oxbow lakes and groyne fields. Due to regulation by weir and lock systems, the River Moselle and its largest tributary the River Saar offer numerous suitable habitats facilitating the rapid further expansion upstream to river reaches in Luxembourg and France.
A total of 79 females of spirlin Alburnoides bipunctatus from the Rudava stream (small lowland stream, Western Slovakia) were examined to obtain data on fecundity and annual oocyte development cycle. Within spawning season (mid- April to early July), the reproduction resources seemed to be allocated in its former half more intensively (more yolked eggs present in ovaries compared to the rest of spawning season). For the mean SL = 76 mm and eviscerated body weight = 7.2 g, mean absolute fecundity of females in pre-spawning phase (n=13) was 3020 eggs (SD = 923; 2695 yolked eggs, SD = 1054), and mean relative fecundity 430 eggs/g (SD = 81; 373 yolked eggs, SD = 100). Number of eggs in the right and the left ovary differed significantly in 63.3 % of females, with a maximum difference of 1405 eggs. Two clues, namely 1) no gap in distribution between immature, unyolked oocytes (present in an ovary throughout the whole year), and yolked (vitellogenic) oocytes, 2) no increase in mean diameter of yolked oocytes towards the end of spawning season, suggest that spirlin is a species with indeterminate fecundity.
After Neogobius kessleri, Neogobius gymnotrachelus, and Neogobius fluviatilis, Neogobius melanostomus is the fourth species of Gobiidae to find its way up the River Danube to Slovakia, occurring in our samples near Štúrovo (river km 1720) and in the River Hron (river km 0.82). The fish (male, females, juvenile) were captured along weakly sloped sandy riverbanks with large stones. The mensural and meristic characters of the specimens were similar to those reported elsewhere for the species.
Five new records of the scale-bearing chrysophytes Mallomonas multiunca, M. paxillata, M. portae-ferreae, M. prora and M. retifera are reported for the Czech Republic. M. multiunca was found in a mesotrophic oxbow lake of the river Vltava. M. paxillata, M. portae-ferreae and M. prora were found in a mesotrophic to eutrophic floodplain pool of the river Lužnice. M. retifera was recorded from alluvial pools associated with the Vltava and Lužnice rivers, respectively. Autecology and distribution of the species are discussed. Three of the species occur in temperate and subarctic regions, M. paxillata probably has a cosmopolitan distribution and M. portae-ferreae prefers warmer water, occurring most frequently in tropical to subtropical regions.
In this paper we define, by duality methods, a space of ultradistributions G ′ ω(RN ). This space contains all tempered distributions and is closed under derivatives, complex translations and Fourier transform. Moreover, it contains some multipole series and all entire functions of order less than two. The method used to construct G ′ ω(RN ) led us to a detailed study, presented at the beginning of the paper, of the duals of infinite dimensional locally convex spaces that are inductive limits of finite dimensional subspaces.
Halobates spp. are the only insects inhabiting the open sea. One sea skater species, Halobates sericeus, was collected at 18 locations in the East China Sea area (27°10´N- 33°24´N, 124°57´E-129°30´E), and H. micans and/or H. germanus at only 8 locations in the area south of 29°47´N, where water temperatures were more than 25°C. At three locations, where the water temperature was less than 23°C, neither H. micans nor H. germanus were caught. The effect of photoperiod on the aggregation and mating behaviour of the sea skater, H. sericeus, was studied under laboratory conditions during a one-month cruise. Adults and 5th instar larvae of H. sericeus, collected between 29°02´N and 30°29´N, were kept under long (14.5L : 9.5D) or short-day (10.5L : 13.5D) conditions at 23 ± 2°C for 20 days. Aggregation and mating behaviour of these sea skaters were recorded over a period of 150 min during the daytime. To analyze the data, the observation period of 150 min was divided into 50 intervals of 3 min. Aggregation was observed more under short than long-days. Duration of a group was much longer under the short (mean ± SD : 43.0 ± 108.1 sec) than long-days (7.6 ± 3.1 sec).
The distribution of Alisma gramineum in the Czech Republic was determined using herbarium specimens, data in the literature and the authors’ own records. Comparison of records from four periods (before 1900, 1901–1945, 1946–1970, 1971–2001) revealed that the total number of localities has not decreased, but the occurrence changed considerably both in terms of the localities and regions where the species is found. Abundant populations were observed on exposed shores of water reservoirs. It has colonized the Třeboň Basin, S Bohemia, over the last few decades. Effect of water regime, light/darkness regime and temperature on germination and dormancy was studied. A. gramineum is adapted to germinate in water and in the dark; germination occurs in late spring, i.e. a period of high temperature. The high variation in the germination response to particular environmental factors may be accounted for the irregular occurrence of A. gramineum at certain localities. Best conditions for seed production are shallow water and recently exposed shores of water reservoirs, where plants can grow and set seed within one growing season. The ability to survive in a vegetative stage is more important in deep water, but seed banks in the mud at the bottom of reservoirs is the only way the species can persist when adult plants die.
The distribution of four alien Reynoutria taxa (R. japonica var. japonica, R. japonica var. compacta, R. sachalinensis and R. ×bohemica), native to East Asia, and history of their introduction to and spread in the Czech Republic was studied. The most widely distributed representative of the genus, R. japonica var. japonica, was first recorded in 1883 by A. Weidmann in cultivation in S Bohemia. The first record outside cultivation is from N Bohemia in 1902. Up to 2000, it has been recorded in 1335 localities, most frequently in riparian and human-made habitats. The dwarf variety R. japonica var. compacta is of a limited distribution that depends on rare cultivation and subsequent escape. The first herbarium specimen was collected in 1948 and the first record out of cultivation is from 1995. R. sachalinensis was recorded in 261 localities. It was first collected in 1921 in Central Bohemia. A herbarium specimen of a plant cultivated in the Botanical Garden of the Charles University in Prague, collected in 1950, has been re-determined as R. ×bohemica, the hybrid between R. japonica var. japonica and R. sachalinensis, and represents the earliest record of the hybrid in the Czech Republic. Since then, this taxon was observed in 381 localities. Herbarium records were used to compare the rate of spread among the three common taxa in 1952–1995, i.e. since when the hybrid started to appear in herbaria. R. japonica var. japonica has been spreading significantly faster than R. sachalinensis and the hybrid exhibits twice the rate of invasion of its parents.
A revision of the diversity and distribution of Potamogeton hybrids in the Czech Republic is presented. Thorough examination of herbarium material and recent extensive field studies revealed the present and/or past occurrence of eight Potamogeton hybrids in the Czech Republic. In addition tomorphological characters, stem anatomy and/or molecular analysis were used to identify some of the hybrids. All the hybrids detected are between broad-leaved species of the genus, suggesting that hybrids between linear-leaved species may be overlooked because of the overall morphological similarity of taxa within this group. Four of the hybrids identified, P. ×nitens, P. ×olivaceus, P. ×sparganiifolius and P. ×undulatus, are recorded for the first time from the Czech Republic. Four of the hybrids are now extinct in the Czech Republic and the extant hybrids are rare. The occurrence of P. ×lintonii was not confirmed; the previous record was based on extreme forms of P. gramineus. The name P. ×concinnitus, proposed for a putative hybrid combination “P. pusillus × P. crispus”, was lectotypified and reduced to a synonym of P. crispus. Although the absolute number of finds of specimens of Potamogeton hybrids per decade is increasing, this is not a result of more frequent hybridization but of an increase in recording activity. Most records for recent decades are associated with targeted research by a few experts. The typical habitat of Potamogeton hybrids in the Czech Republic are ponds that were previously drained in summer and allowed to dry out. Many historical localities disappeared when the traditional fishpond management was largely abandoned and fish farming become more intensive. In the 19th century in particular some hybrids were recorded also in rivers but these occurrences generally disappeared after the extensive channelling of rivers at the beginning of the 20th century. Many hybrids occur at the same localities as their parents but it is documented that hybrids can persist vegetatively in the absence of the parental species, presumably as relics of the previous presence of the parent plants. Although almost all Potamogeton hybrids are consistently sterile, a cultivation experiment showed that P. ×angustifolius set seeds that were fertile and successfully produced adult plants.