摘要:

AbstractThe intracellular and extracellular contents of K, Mg and Ca, dry weight and CO2exchange rates in successive 2-cm segments ofRhytidiadelphus squarrosus(Hedw.) Warnst, were recorded before and after storage of moss shoots collected from the field. Moss shoots sustained apical growth in the absence of aerial or substratum nutrient inputs and acropetal transfer of cations occurred at the expense of basal segments. Intact shoots of 12–17 cm initial length showed increased or decreased cation contents, respectively, in the uppermost segments according to whether infrequent or frequent watering regimes were employed. Excised shoots of 4 or 8 cm retained cations despite a frequent watering regime. Acropetal transfer of cations during growth of excised shoots was in proportion to the available cation pool. There was no evidence that nutrient limitation in the growing apex affected growth or metabolism. Pre-treatments which modified the initial Ca, Mg and K status of moss shoots did not influence the pattern of recovery of elements in newly-grown apices but showed that exchangeably bound extracellular cations were readily available for acropetal transfer. Results indicate that efficient internal recycling of nutrients can sustain growth. of bryophytes and are discussed in relation to the pathways and mechanisms of nutrient redistribution.

ISSN:0373-6687    

DOI:10.1179/jbr.1996.19.1.1

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractAlthough ozone is generally accepted to be an important phytotoxic air pollutant little is known of its effects on natural and semi-natural vegetation. In this study four species of Sphagnum, common to upland areas, (S. capillijolium(Ehrh.) Hedw.,S. cuspidatumHoffm.,S. papillosumLindb. andS. recurvumP. Beauv.) were exposed to acute ozone episodes,ie. 150 ppb (nl 1-1), for 6 hours at low temperature (5°C), in controlled chambers. The fumigation protocol caused a significant reduction in photosynthesis of treated plants in comparison to control plants for one species,S. recurvum, as measured by CO2assimilation and chlorophyll fluorescence. Membrane leakiness, measured by efflux of potassium ions, was increased. The three other species studied,S. capillijolium, S. cuspidatumandS. papillosumwere not sensitive to the ozone exposure. ForS. recurvumthe ratio of variable to maximal fluorescence (Fv/Fm ratio) was significantly reduced following ozone fumigation at 150 ppb (by an average of 21%). CO2assimilation of ozone treatedS. recurvumwas also significantly reduced in comparison to the control plants by approximately 50%.S. recurvumalso showed significantly increased membrane leakiness following treatment with ozone. Bryophytes by the very nature of their morphology and physiology are, perhaps, more likely to be susceptible to short-term acute ozone episodes and these results are discussed in relation to their potential ecological significance.

ISSN:0373-6687    

DOI:10.1179/jbr.1996.19.1.19

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractPorothamnium frahmiiEnrothsp. nov. (Neckeraceae, Musci), known from Colombia and Peru, is described and illustrated. It is compared withPorotrichum substriatum(Hampe) Mitt.,P. longirostre(Hook.) Mitt.,Porothamnium filiferum(Mitt.) Fleisch., andP. expansum(Tayl.) Fleisch., with which it might be confused. The sporophyte ofPorotrichum substriatumis described for the first time.Porothamnium stipitatum(Mitt.) Touw ex De Sloover, previously known only from Africa, is reported from French Guiana.

ISSN:0373-6687    

DOI:10.1179/jbr.1996.19.1.33

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractWeissia radians Hedwig is one of twelve names for Australasian mosses published in Hedwig'sSpecies Muscorum Frondosorumin 1801. While ten of the Hedwigian names (in their modern combinations) are used in twentieth-century Australasian floras,Weissia radianshas fallen into obscurity. Although no type specimen exists in the Hedwigian herbarium (G), a Joseph Banks collection from New Zealand is present in the Dawson Turner herbarium (BM). I believe the Banks material to be a portion of the original collection and here propose it as the lectotype ofW. radians. A combination based upon this basionym,Entosthodon radians(Hedw.) C. Müll., is the most appropriate name for this widespread Australasian species, which recent Australasian workers have misnamed asFunaria glabraTayl. The type of F. glabra Tayl., collected by James Drummond at Swan River in Western Australia, is referable toEntosthodon muehlenbergii(Turn.) Fife, a species widely distributed worldwide but rare in Australia and New Zealand. Synonymy is provided for these two species and their Australasian distributions are summarized. A lectotype is designated forEntosthodon claviformisC. Müll.&Hampe, a name that has been placed incorrectly in synonymy withFunaria glabraTayl., but which is here referred toEntosthodon apophysatus(Tayl.) Mitt. Evidence is presented that past selections of lectotypes for other Australasian Hedwigian names may have been inappropriate.

ISSN:0373-6687    

DOI:10.1179/jbr.1996.19.1.39

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractA group of Australasian micro-Fissidens, which at various times have been placed in two genera and some 15 different species, are regarded as four varieties of the single species,Fissidens tayloriiC.Muell., in SectionFissidens, SubgenusFissidens. Descriptions, illustrations and a key to the varieties are provided.

ISSN:0373-6687    

DOI:10.1179/jbr.1996.19.1.49

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractA revision of the African species ofSplachnobryumis presented. Only three species are accepted, viz.S. aquaticumC. Müll.,S. gracileBesch. andS. obtusum(Brid.) C. Müll. The species are illustrated and .described. The occurrence of rhizoidal tubers inS. obtusumis reported.S. acutifoliumThér. is placed inBryum. S. erosulumC. Müll. ex Dus. andS. tenerumC. Müll. ex Dus. are placed inGymnostomiella. Seven other AfricanSplachnobryumspecies and two varieties are reduced to synonomy withS. obtusumorS. gracile.

ISSN:0373-6687    

DOI:10.1179/jbr.1996.19.1.65

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractSarsen stones, hard acidic rock fragments, are restricted to just six sites in southern England but they provide an important habitat for both lichens and bryophytes. The bryophytes of sarsen stones have received less attention than the lichens but they include many species that are. either rare or absent throughout the region, or occur only in man-made habitats such as in churchyards or on roofs. Members of theGrimmiaceaeare well represented includingGrimmia decipiens, G. laevigata, G. trichophyllaandRacomitrium heterostichum. Other notable species includeHedwigia ciliata s.s., H. stellata, Pterogonium gracileandPorella obtusata. Unlike the lichen flora there is no maritime element among the bryophytes of sarsen stones, but shared with the lichens is a clear upland element. Thisis in a large part a reflection of the scarcity of hard acidic rock outcrops in southern England; many of the notable species occurring on sarsen stones are more common in the upland areas of west and north Britain where suitable rock is extensive. A comparative assessment of the status of some of the more notable species in southern England demonstrates the high bryological importance of sarsen stones. Although the existing sarsen stone sites are to some degree protected, they occur within a farmed landscape and the widespread use of agricultural chemicals and the impact of grazing need to be carefully monitored. Air pollution may also be a contributory factor in the decline and loss of certain sarsen stone species.

ISSN:0373-6687    

DOI:10.1179/jbr.1996.19.1.79

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractSt Kilda is a remote but exceptionally interesting archipelago in the North Atlantic. Its rich bryoflora has not previously been documented. A list of the mosses and liverworts from the main island, Hirta, is given, including published records and additional species recorded on separate visits by the authors in 1959 and 1991. A total of 160 species is reported, comprising 56 liverworts and 104 mosses. The richness and phytogeography of the bryoflora of Hirta is discussed in relation to climate, ecology and vegetation history and is compared with similar studies on other islands.

ISSN:0373-6687    

DOI:10.1179/jbr.1996.19.1.89

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractFour members of the moss family Erpodiaceae,Aulacopilum trichophyllum, Erpodium beccarii, E. coronatumandE. grossirete, collected during the 1991 British Bryological Society expedition to Mulanje Mountain, are recorded as new for Malawi.

ISSN:0373-6687    

DOI:10.1179/jbr.1996.19.1.113

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractThe genusCampylopusis represented in Africa by 40 species, subspecies and varieties, of which 27 have been found in Malawi,AtractylocarpusandBryohumbertiaby two species each (one of each found in Malawi), andMicrocampylopusby one species, which has been found in Malawi. Twenty five of the 30 members of this group recorded for Malawi were found on the BBS Expedition. The paper includes a diagnostic key to all African species and varieties of the group, and the distribution of the taxa in Malawi is discussed in relation to the rest of Africa.Campylopus flaccidusRen.&Card. var.cucullatifoliusJ.-P. Frahm is described as a new combination.Atractylocarpus madagascariensis(Thér.) Padberg&Frahm andCampylopus arcuatus(Brid.) Jaeg. are newly recorded for mainland Africa, andCampylopus bartramiaceus(C. Müll.) Thér.,C. catarractilis(C. Müll.) Par.,C. dicranoidesThér.&Nav.,C. flexuosus(Hedw.) Brid.,C. hildebrandtii(C. Müll.) Jaeg.,C. incacorralisHerz.,C. johannis-meyeri(C. Müll.) Par.,C. praetermissusFrahm andMicrocampylopus laevigatus(Thér.) Giese&Frahm are reported as new to Malawi.

ISSN:0373-6687    

DOI:10.1179/jbr.1996.19.1.119

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor