Barbula maxima,nom. nov., an endemic Irish species

Abstract

Rhizoidal tubers from field and cultured Ditrichum heteromallum are described and figured and differ in morphology from those of other mosses so far described. Protonemal gemmae are also produced in culture.     

The taxonomy of Campylopus pyriformis (Schultz) Bridr and related species

Abstract

Twenty-five species of mosses collected in Costa Rica, mostly in 1965, are recorded. Leptodontium ramosum, remarkable for its peg-like gemmae borne on stout leafless branches, Sematophyllum serrulatum and Trichosteleum sarapiquensis are described as new species.     

Colourless tubers in Discelium nudum Brid

Abstract

Colourless, usually unicellular, tubers occur on the rhizoids of Discelium nudum. They are evidently not the rhizoid gemmae previously claimed to occur in this species, which were multicellular.     

A Bryophyte Flora of Wigtownahire

Abstract

Fissidens macaoensis L. Zhang is described as a new species from Macao, South China. The species can be separated from its congeners by a suite of characters, including (1) minute size; (2) subterraneous tubers, composed of one to several cells, growing laterally from mature rhizoids; (3) abundant rhizoidal gemmae found on the surface of the soil and which are developed from subterraneous rhizoids; and (4) relatively large cells of the leaf lamina. This is the first report of a moss where two types of vegetative diaspores occur simultaneously in a single individual. Their adaptation strategy is briefly addressed.     

中国藓类植物无性繁殖体的初步观察

无性生殖在苔藓植物的生活史中起着重要的作用,并且常通过各种无性繁殖体来完成。无性繁殖体的形态常被用来辅助鉴定一些不育的藓类植物。本文通过对38种藓类植物的无性繁殖体进行显微观察,结果显示：无性繁殖体在不同的藓类植物之间已经过多次演化;无性繁殖体的形态在种内是相对稳定的,且与其着生位置、配子体的分枝方式密切相关,而与植物的系统位置以及生境并无直接的关系;无性繁殖体的颜色与其胞壁的厚度以及表面纹饰密切相关。此外,无性繁殖体的产生常常与假根、原丝体有共存关系。在研究中发现,藓类植物的无性繁殖体主要包括原丝体芽胞、无性芽胞（叶生芽胞、中肋芽胞、枝生芽胞）、芽体、假根芽胞和假根状块茎;其中原丝体芽胞和无性芽胞最为常见。     

Bryophytes in Chawley Brick Pit,Oxford, 1948–1985

Abstract

Chawley Brick Pit, Oxford fell into disuse in 1935 and provided a variety of habitats which Were exceptional for the district, especially on wet sand and clay, in which many locally rare species of bryophyte appeared. By 1948 it had a rich bryophyte flora which was still being added to by new immigrants, many of which must have come from at least 30–60 km distance. Between 1966 and 1985 the development of woodland and the natural evolution of the soil had eliminated most of these early immigrants but some other equally remarkable shade-tolerant species had arrived. About half of the hepatic species must have come as spores, and the other half either as, spores or gemmae. Many of the immigrant mosses are dioecious and fruit rarely but spores, nevertheless, seem the most likely means of introduction for most of them.     

A contribution to the moss flora of the Cape Provinces (South Africa)

Abstract

Several first records of mosses are reported for continental sub-Saharan Africa, Southern Africa or the Cape Provinces as well as the occurrence of subterranean tuberous stolons in Pleuridium ecklonii and rhizoidal tubers in four acrocarpous mosses, viz. Archidium globiferum, Ditrichum difficile, Fissidens beckettii and Pleuridium nervosum.     

A small collection of mosses from Sulawesi

Abstract

A collection of mosses made by Mr M. J. E. Coode in Sulawesi, comprizing 37 species, is reported upon. Five species appear to be unrecorded for this still bryologically littleknown island. Taxitheli'um capillarisetum appears to be the first gathering since the type collection (in New Guinea).     

Notes on the nomenclature of British mosses. I

Abstract

Gemmae found on the protonema of Barbula trifaria are described. The protonemal gemmae of this species and of Gyroweisia tenuis and Eucladium verticillatum, in addition to those recently reported in Schistostega pennata, seem to be adaptations for survival and propagation at low light intensities.     

Some noteworthy bryophytes from Tenerife

Abstract

Mosses exhibit a greater variety of cellular separation mechanisms than any other group of land plants. Diaspore liberation mechanisms range from (1) the random breakage of thin-walled stalk cells to (2) the formation of new internal walls that separate from the old walls, (3) severance along the middle lamella of the basal cell with or without the rounding off of the cells, (4) the formation of highly specialized abscission or tmema cells and (5) breakage along an intercalary region of thinwalled living cells. Rhizoidal gemmae are the only propagules lacking a separation mechanism other than by the decay of the filament system that produces them. In some species, two and sometimes three different kinds of diaspore are formed simultaneously in culture. Diaspore germination patterns in mosses are even more diverse than the liberation mechanisms. With a few exceptions new growth from diaspores is filamentous. Most diaspares are highly polarized and the germination pattern is fixed during development. Protonemal and rhizoidal gemmae are defined on the basis of the filament systems that produce them and from the presence or absence of specialized abscission mechanisms.     

Arbuscular mycorrhiza and water and nutrient supply differently impact seedling performance of dry woodland species with different acquisition strategies

Background: We recently demonstrated that dwarf male plants are much more common among mosses than hitherto thought. Dwarf plants, producing functional male sexual organs occur in 10–20% of the moss species worldwide.

Aims: We investigated how an inadvertent omission of dwarf males affects estimates of male sex expression rates and sex ratios.

Methods: We recorded frequencies of specimens with female-expressing plants, male-expressing normal-sized and/or dwarf plants, and sporophytes in herbarium material of five model species from Macaronesia. We analysed how frequency estimates of male occurrence and sex ratios were affected by excluding dwarf males.

Results: Occurrence of dwarf males was positively associated with sporophyte formation. When dwarf males were excluded, male mate availability was missed in 51–61% of specimens (in 74–76% of sporophyte-containing specimens). Specimen-level sex ratio was balanced in material with sporophytes in the three species exhibiting male dwarfism, but strongly female biased if dwarf males were omitted.

Conclusions: We provide the first quantitative evidence that sex-expressing dwarf males are essential for sexual reproduction and sporophyte production in mosses that form such males. Considering its abundance, male dwarfism therefore deserves more attention among plant biologists. Innovative approaches are required to further study the minute male plants.     

Proceedings, 1960

Abstract

A survey of mosses undertaken on the plateau region of Zambia resulted in the collection of eighty-eight species representing twenty-eight families. A total of seventy-three species of mosses have been reported from Zambia up to 1983, but this report provides an additional sixty-one species The preliminary pattern of distribution reveals that out of the eighty-eight species collected, sixty-two occur in the woodlands and riparian forests while twenty-six are restricted to the humid, waterfall sites.     

A cytological study of Pellia epiphylla (L.) Corda in Britain with reference to the status of Pellia borealis Lorbeer

Abstract

The history of Pellia borealis is outlined and its morphology compared with that of P. epiphylla. The techniques for preparing material for chromosome counts are described. Several gatherings of monoecious Pellia with large epidermal cells (P. borealis) were found to be haploid, n = 9. The size of the epidermal cells is shown to be valueless as a character for distinguishing the two species. It is concluded that only P. epiphylla should be retained as a species.

We wish to record our thanks to Dr S. Arnell for examining British material and for helpful correspondence; to Dr A. J. E. Smith for his valuable advice and criticism, and for the use of cytological facilities; and to all those who have contributed material of possible P. borealis.     

Macromitrium maolanense Zeyou Zhang,D.D.Li,Jing Yu & S.L.Guo,a new species from China based on molecular and morphological evidence

Introduction. During a field excursion in Guizhou Province, China, we collected some interesting moss specimens with branch leaves subulate in the upper part, partially and variably bistratose laminae, and a Macromitrium-like epiphytic growth habit on tree trunks. We present morphological and phylogenetic arguments for recognising these plants as a new moss species in the genus Macromitrium Brid. (Orthotrichaceae).

Methods. We compared the morphology of the potential new species with closely related species of Macromitrium, and constructed a phylogenetic tree based on ITS2, trnL and trnG including sampling from 14 other morphologically similar species of Macromitrium.

Key results. The proposed new species belongs to the genus Macromitrium (Orthotrichaceae, Musci). It is closely related to M. gymnostomum Sull. & Lesq. in the phylogenetic tree and according to gametophytic morphological features, represents a hitherto undescribed species.

Conclusions. A new moss species, Macromitrium maolanense Zeyou Zhang, D.D.Li, Jing Yu & S.L.Guo, is described and illustrated. The new species can be distinguished from all congeners by the combination of the following features of the branch leaves: (1) oblong-lanceolate, lanceolate to linear-lanceolate, gradually narrowed to an easily broken subula; (2) rather obscure upper and medial cells, often with blackish stains among cells, densely pluripapillose; (3) variably and partially bistratose laminae in the upper 1/3 portion; (4) basal cells clear, hyaline and smooth, those near costae forming a ‘cancellina region’; and (5) with numerous brownish, clavate gemmae on upper portion. We also discuss the principal distinctive characters separating the new species from its nearest congeners.     

Chlorophyll concentrations and a/b ratios in mosses collected from exposed and shaded habitats in Kansas

Abstract

Chlorophyll concentrations and a/b ratios of 31 moss species in 16 families collected from various habitats in Kansas were lower than those of most higher vascular plants. Most of the mosses examined had higher chlorophyll concentrations and lower chlorophyll a/b ratios when collected from habitats with low solar irradiance, relative to mosses collected from habitats characterized by high irradiance. This was true for mosses collected from under a forest canopy compared with those collected from exposed sandstone outcrops, and for the same populations of mosses collected before and after forest canopy closure. Such changes in the characteristics of the light-harvesting pigment system appear to represent adaptations enhancing the efficiency of light capture.     

Distribution Maps of Bryophytes in Britain

Abstract

Flask-shaped gemmae of British Leptodontium flexifolium (With.) Hampe are discussed in the context of previously described ellipsoidal and oboyoid gemmae and point to the need for taxonomic reappraisal of the two closely related species, L. flexifolium and L. styriacum (Jur.) Limpr.. Scabrous leaves in the former are associated with mamillae rather than papillae.     

Protonemal gemmae on Amblystegium serpens (Hedw.) B., S. & G. from Macquarie Island

Abstract

Amblystegium serpens, collected on Macquarie Island, formed protonemal gemmae in laboratory culture. The gemmae germinated to form leafy shoots. They are presumed to be vegetative reproductive structures.     

Two new species of Cololejeunea from Peninsular India

Abstract

Two new species of Cololejeunea (sub-genus Lep tocolea), C. pandei sp. nov. and C. dentifolia sp. nov. are described from fudia. Both species are epiphyllous with ascending leaves. The former is characterized by uniseriate stylus, serrated margin of leaf, discoid gemmae on ventral surface of leaf-lobe with 2-3 mamillose cells and inflated perianthwith lateral winged plicae. The latter is characterized by dentate margin of leaf, leaf-cells with distinct trigones and intermediate nodular, thickenings, bidentate leaf-lobule and discoid gemmae with 4 mamillose cells.     

Notes on Fissidens

Abstract

Protonemal gemmae in Schistostega pennata are reported and described from Britain for the first time; they are compared particularly with those from the Australasian moss Mittenia plumula.