摘要:

AbstractSince 1794 about 1.3 species per year have been added to the known bryophyte flora of Oxfordshire.This is chiefly due to taxonomic research combined with diligent and intelligent collecting but it is also partly due to the immigration or at least the increasing frequency of some species. Twenty- five species (ca7% of the flora) have not been recorded during the present century, and may be extinct, but many more have declined in frequency. The paper seeks to elucidate the extent and the causes of such changes; for this purpose much evidence from other districts is reviewed.Apart from the physical destruction of local specialized habitats and the creation of new habitats, the more important causes of widespread change have been: (a) eutrophication of both land and water, partly as a result of (b) changes in agricultural practice, including the heavy application of fertilizers, and immediate ploughing and resowing after harvest; (c) a decline in grazing, especially by rabbits; (d) changes in forestry practice, including the cessation of coppicing and the planting of conifers, increasing the amount of decaying woody material; (e) most far-reaching of all, widespread but slight atmospheric pollution, the effect of which seems to be due to‘acid rain’rather than to toxic SO2.Factors (d) and (e), though adverse for basiphil species, have favoured acidiphil species, at least eight of which have increased in frequency. An additional four acidiphil species first recorded in the county since 1935 have remained rare, but evidence from other districts suggests that they are increasing.Some dioecious mosses formerly fruited more freely in Oxfordshire than they do now.

ISSN:0373-6687    

DOI:10.1179/jbr.1991.16.4.513

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractPeroxidases in 21 samples ofLophozia incisafrom the Tatra Mountains and 14 samples ofL. opacifoliafrom the Tatra Mountains and the Swiss Alps were electrophoretically assayed. Although both taxa proved to be polymorphic, consistent differences were found between them. This indicates that electrophoretic peroxidase phenotypes provide an additional taxonomic character supporting the morphological and ecological differences, a summary of which is provided.

ISSN:0373-6687    

DOI:10.1179/jbr.1991.16.4.551

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractGymnostomum calcareumNees&Hornsch.,G. viridulumBrid. andG. mosis(Lor.) Jur&Milde are recognized as distinct species on the basis of their morphology and from culture studies. The best distinguishing characters are the elongated leaves ofG. calcareum, the biseriate axillary and protonema-gemmae of G. viridulum,and the bistratose regions near the leaf margins, and nerve 50μm wide, inG. mosis. Sporophytes are unknown inG. mosis. G. calcareumhas a world-wide distribution,G. viridulumoccurs in southern Europe, north Africa and the Middle East, andG. mosisseems to be confined to the Middle East.

ISSN:0373-6687    

DOI:10.1179/jbr.1991.16.4.561

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractP. andrewsiiappears to be widespread in the arctic regions of the U.S.S.R. and also in mountains of southern Siberia, the Altai Mountains. Except in the mountains of Central and Northern Europe the range ofP. andrewsiidoes not overlap withP. annotinaandP. camptotrachela.

ISSN:0373-6687    

DOI:10.1179/jbr.1991.16.4.581

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractCalymperes schmidtiiBroth.inJ. Schmidt andC. subintegrumBroth.inJ. Schmidt, hitherto regarded as conspecific, are shown to represent distinct species.

ISSN:0373-6687    

DOI:10.1179/jbr.1991.16.4.589

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractCalymperes subintegrumBroth.inJ. Schmidt is newly recorded for Sri Lanka. A form ofSyrrhopodon confertusLac. with leaves showing some similarities to those of Exostratum is described and discussed.Calymperes mayottenseBesch. is lectotypified and confirmed as a synonym ofCalymperes afzeliiSw.

ISSN:0373-6687    

DOI:10.1179/jbr.1991.16.4.595

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractEntodon dregeanus(Hornsch.) C.M., from Africa aridE. plicatusC.M., from southern India and Ceylon, are reduced to the synonymy ofE. macropodus(Hedw.) C.M., an American species.

ISSN:0373-6687    

DOI:10.1179/jbr.1991.16.4.601

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractThe presence of a conspicuous group of alar cells precludesDitrichum subaustralevar.robustumfromDitrichumand accordingly it is transferred toDicranoweisiaasDicranoweisia antarcticavar.robustum(Card.) Seppelt, comb. nov.

ISSN:0373-6687    

DOI:10.1179/jbr.1991.16.4.607

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractPinnatella mariei(Besch.) Broth.(Neckera marieiBesch.) is transferred from the Neckeraceae to the Leptodontaceae and recognized as the single species of its genus:Caduciella mariei(Besch.) Enroth,gen. et comb. nov.The transfer and recognition of a new genus are based on vegetative characters since the gametoecia and sporophytes are unknown. The Leptodontaceae is tentatively recognized as being composed of the generaLeptodonMohr,CaduciellaEnroth,CryptoleptodonRen.&Card., andForrstroemiaLindb. Lectotypes are selected for Neckera mariei andPinnatella micropteraFleisch.Caduciella marieiis recorded for the first time for China and Australia.

ISSN:0373-6687    

DOI:10.1179/jbr.1991.16.4.611

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractA number of chemical habitat parameters for the speciesScorpidium scorpioides, S. cossoniiandS. revolvenswere investigated in three areas in northern and southern Sweden.S. revolvensoccurs in a much narrower range of some parameters, especially pH and conductivity, than the other two species. When pH and conductivity are considered together,S. revolvensandS. cossoniiare almost completely mutually exclusive.

ISSN:0373-6687    

DOI:10.1179/jbr.1991.16.4.619

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor