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Isoëtes todaroana, a new species from western Sicily (Italy), is described. Morphological, anatomical and ecological characters are given. The main differential characters are the presence of only two leaf air chambers, rather than four as in all other known species of the genus, and the shape of the scales, which have two lateral rounded lobes and one central spine-like lobe, together with its peculiar calcophilic habitat. So far, the species is known from a single locality.
Neolepisorus dengii, N. dengii f. hastatus and N. emeiensis f. dissectus should be considered synonyms of N. emeiensis. This treatment is justified on the basis of complete intergradation of the frond forms that supposedly separate these taxa. The intergradation can be found on the same individual.
Botrychium ascendens is reported from Fogo Island in Newfoundland as an addition to the flora of the province. Fogo Island plants are identical to plants in western North America, including those from the type locality, in comparisons of leaf morphology, spore size, and allozyme expression. Comparisons are made with related and confusing taxa, B. campestre, B. crenulatum, B. lineare, and the American genotype of B. lunaria. Newfoundland plants display a high level of fixed heterozygosity and large spore size, indicating they are allotetraploid, and supporting suggestions that B. ascendens is derived from ancient hybridization between B. crenulatum and the B. lineare/campestre complex. The current distribution of Botrychium ascendens and its putative parents suggest it probably originated in western North America and migrated across northern Canada to Newfoundland.
The variables affecting spore phenology have been poorly studied in contrast with the abundant literature on leaf phenology. This paper deals with the influence of altitude and canopy cover on spore maturation and release of Culcita macrocarpa and Woodwardia radicans in the island of São Miguel, Azores. The study was conducted during one sporing season at three altitudes (400, 600, and 800 m). In both species spore maturation occurred in autumn and may be controlled by the previous accumulation of photosynthates. Spores were not released until late winter owing to a requirement for dry weather conditions. Dispersal took place later at higher altitude, due to lower temperature and higher humidity. This gradual liberation of spores along an altitudinal gradient is important for the endemic Azores bullfinch Pyrrhula murina (a bird that feeds on spores in winter), providing food over an extended period.
—In the homosporous fern Ceratopteris richardii, sex is not determined chromosomally. Rather, hermaphroditic gametophytes produce a hormone called antheridiogen, which induces maleness in undifferentiated gametophytes. The percentage of males increases with increasing density of gametophytes, presumably due to the cumulative effect of antheridiogen from multiple hermaphrodites.
Some have argued that antheridiogen lessens competition between gametophytes. Such competition is expected to be most intense between hermaphrodites given that they support zygote, embryo, and sporophyte growth. Therefore, it is predicted that at lower nutrient levels, the effect of antheridiogen in inducing male gametophytes is greater than at higher nutrient levels.
To test this hypothesis, C. richardii spores were sown over a range of densities (0.52/cm2 to 5.2/cm2) in four nutrient-level treatments (100, 50, 25, 12.5 percent of full-strength nutrient agar). Gametophytes were grown for four weeks at 28 degrees Celsius with a photoperiod of 14 L: 10 D. An ANCOVA found an overall positive relationship between gametophyte density and percentage of male gametophytes. However, the relationship between gametophyte density and percentage of male gametophytes did not differ among nutrient levels. Nutrient levels had no effect on the rate of male induction by antheridiogen. A post-hoc power analysis showed that the experimental power was 97%.
Adult tree ferns of the genera Cyathea and Alsophila are frequently harvested from tropical forest remnants near the city of Cuetzalan (Puebla, Mexico). Local artisans use the adventitious roots that surround tree fern stems as substrate to make handicrafts. In this region, tree ferns regenerate abundantly in disturbed areas such as roadsides, in which they suffer high mortality due to weeding and other road maintenance activities. Transplantation of young tree ferns from these areas to safe sites could contribute to the ex situ conservation of the species. The sale of transplanted tree ferns could also provide local families with an additional source of income. We identified and estimated the abundance of all tree fern species that occurred along roadsides in this region. We evaluated the viability of transplanting young tree ferns of Cyathea divergens and Alsophila firma to different conditions of light availability. While only 30% of the individuals naturally growing along roadsides survived for 1 year, C. divergens transplants experienced 73.3 and 86.7% survival and A. firma transplants experienced 93.3 and 40% survival when planted in safe sites under open canopy and in 50% shade, respectively. Transplants of C. divergens produced more fronds and grew faster in height than transplants of A. firma. Individuals of both species transplanted to 50% shade produced more fronds and grew faster than conspecifics transplanted to open canopy areas. Transplantation proved to be a low time- and cost-demanding strategy to promote conservation of native tree fern populations while providing local people with a potentially profitable alternative to replace handicraft production.
We conducted a survey on the mycorrhizal status of neotropical ferns, focusing on previously neglected taxa. These include the filmy ferns (Hymenophyllaceae), grammitid ferns (Polypodiaceae), and the genus Elaphoglossum (Dryopteridaceae). Samples were collected at different sites in southern Ecuador, Prov. Loja, Morona-Santiago, and Zamora-Chinchipe. Among the 85 investigated species (101 samples, 10 families), 19 were associated with arbuscular mycorrhizal fungi (AMF) and 36 were infected by dark septate endophytes (DSE), which are identified as ascomycetes and here considered as a kind of mycorrhiza similar to the ericoid type. The roots of 30 species (including all non-grammitid Polypodiaceae and half of the Elaphoglossum species) were free of evident fungal infection. AMF were frequent in terrestrial species (29.10% of species, or 48.49% of infected terrestrial samples). DSE prevailed in epiphytic species (58.62% of species, or 96.15% of infected epiphytic samples) and were also common in terrestrial samples of predominantly epiphytic species.
Despite the large number of comparative studies on species with different distribution and abundance, no clear general pattern of attributes explaining species' rarity has yet been found. The relationship between different life-history traits of a species and abundance tend to be conditional and context dependent. We were interested in whether the local relative population density of three fern species in Estonia is related to post-emergence growth of their young sporophytes, i.e., that the locally abundant species, D. carthusiana, has the highest vegetative growth in its first growth periods and the two less abundant species, D. dilatata and D. expansa, have lower. We were also interested in differences between generative traits of young sporophytes of three species, specifically in the number of spores. We grew the species in a garden experiment for two vegetation periods, 2004–2005, until the first sporulation. The relative population density of the three Dryopteris species was related to the relative post-emergence growth of the species. The most abundant species D. carthusiana, exhibited the highest values of vegetative growth parameters in the first growth period. The less abundant D. dilatata and D. expansa both had shorter fronds, shorter intensive growth periods and lower leaf elongation rates. Dryopteris dilatata had a different vegetative growth strategy compared to the other two species; it differed in timing of intensive growth of frond length and increase of frond number and had the lowest values of generative parameters among the three species.
Marsilea quadrifolia, an amphibious fern, has the ability to develop heterophyllous, aerial and submerged leaves. In contrast to submerged leaves, aerial leaves have trichomes on both surfaces. To examine if the presence of trichomes can reflect excess light and hence reduce the risk of being damaged by excess light, we compared the optical properties and chlorophyll a fluorescence, in particular the maximum PSII photochemical efficiency (Fv/Fm), of M. quadrifolia leaves with trichomes (intact) and those having trichomes removed (de-trichomed). Photosynthetic gas exchange measurements were also conducted to quantify transpirational water loss and instantaneous water use efficiency (WUE) of M. quadrifolia intact and de-trichomed leaves. The results showed that removal of trichomes neither affected the optical properties in the visible part of the solar spectrum nor the midday depression of Fv/Fm values of leaflets. In contrast, significantly increased in transpiration rates and decreased rates in WUE were found in de-trichomed leaflets in comparison to intact ones. These results imply that the presence of trichomes is of more importance in reducing water loss than in reflecting light and protecting M. quadrifolia against the potentially damaging effect of photoinhibition in aerial environments.