Notes on water relations of Polytrichum commune Hedw.

Abstract

Water loss in the endohydric moss Polytrichum commune was found to be controlled by a complex series of leaf arrangement changes, and by changes in water potential deficit of the shoots. This contrasted with the water relations of the ectohydric moss Rhacomitrium lanuginosum in which there was apparently little control over loss. Water conduction in Polytrichum was predominantly internal under high evaporative flux, and external under moderate flux, but under many stress conditions both pathways would probably be necessary to maintain an optimum water balance.     

Chromosome studies on some British and Irish mosses. I

Abstract

An electron microscope study of experimental and environmental lead poisoning of leaf cells from the moss Rhytidiadelphus squarrosus (Hedw.) Warnst. is described. Plants treated with lead acetate and lead chloride solutions, or collected from roadsides exposed to lead pollution from motor exhaust gases have been used. The results are compared with other studies of experimental lead poisoning in both plants and animals, with particular regard to uptake mechanisms and to lead accumulating at different sites in the cell. We have shown that lead may be bound within the cell wall, and that it may also enter the cytoplasm. Pinocytosis was observed in leaf cells from moss plants treated with lead salt solutions. Via pinocytotic vesicles within the cytoplasm the particles containing lead could then be discharged into the vacuole. In the leaf cells of mosses exposed to environmental pollution the protoplasmic lead was found to be bound within the nucleus, and was easily identified as electron-dense, nuclear inclusions.     

An adaptative pattern for water conduction in the ectohydric moss Zygodon viridissimus var. rupestris Hartm.

Abstract

A detailed LM, SEM and TEM study of the dorsal and ventral surfaces of the leaf of the ectohydric moss Zygodon viridissimus var. rupestris (Z. baumgartneri) is described. The presence of papillae on both surfaces is confirmed and a groove, running the length of the nerve, is demonstrated. The presence of waxy particles on both surfaces is also demonstrated. A pattern for water conduction which could represent another interesting example of eco-physiological adaptation in bryophytes, is suggested.     

Notes on some British Barbulas

Abstract

The moss Hypnum cupressiforme var. heseleri is reported new to the British Isles and its status is discussed. Line drawings and a photographic illustration are provided. It was found growing on an apple tree on the Royal Estate, at Flitcham in West Norfolk. It differs from other species of Hypnum in its distinctive rounded-concave leaf form and julaceous branches. The habitat and ecology are broadly similar to those in the other European sites from which this moss has been reported.     

Arvernella microclada Hugonnot & Hedenäs (Amblystegiaceae), a new minute species from France,requiring a separate genus

Abstract

Arvernella microclada Hugonnot & Hedenäs is described from several localities in the Massif Central of France (Auvergne). This diminutive, autoicous, pleurocarpous moss has strongly prorate distal ends of the leaf lamina cells and straight and erect inner perichaetial leaves. It bears a superficial resemblance to small Heterocladium Bruch & Schimp. species, especially H. flaccidum (Schimp.) A.J.E.Sm. or weak phenotypes of H. wulfsbergii I.Hagen. Other small confervoid species, like Platydictya jungermannioides (Brid.) H.A.Crum or Serpoleskea confervoides (Brid.) Loeske differ in several respects, most notably in the absence of abaxial leaf lamina cell prorations, but also in rhizoid topography (Platydictya) and leaf orientation and leaf margin denticulation (Serpoleskea). Arvernella microclada grows in subalpine tall-herb communities and Fagus sylvatica L. mountain woods on small lava blocks on cold, unstable, and steep scree slopes. The restricted known geographical distribution may be of conservation concern.     

Recent Bryological Literature, 50

Abstract

Streimannia turgida from the Brindabella Range in the Australian Capital Territory is described as a new genus and species of the Brachytheciaceae. It is a peatland moss having deeply concave, ovate to ovate-lanceolate and reflexed-apiculate leaves with margins entire or merely faintly serrulate above; very variable, double or more rarely single and branched costae reaching 1/3–1/2 the leaf length; thickwalled and po rose cells at the leaf insertion; thin-walled and hyaline angular cells forming rounded, pellucid and excavate auricles.     

On Barbula munyensis R.S.Williams (Pottiaceae), an overlooked species from the tropical montane forest of South America

Abstract

Barbula munyensis R.S.Williams, a neglected moss species known only from the type material collected in central Peru in 1923, is newly reported for the moss floras of Argentina and Bolivia. The species is described, illustrated, mapped, and its habitat preferences are provided. Diagnostic characters and differentiation from some closely related South American taxa, with which it may be confused, are discussed. Barbula orizabensis Müll.Hal., a similar taxon, is excluded from the South American moss flora.     

Gradsteinia torrentfcola,a new aquatic moss species from Tenerife

Abstract

Gradsteinia torrenticola Ochyra, Schmidt & Bültmann sp. nov. (Donrichardsiaceae), known from a single locality in a waterfall on Tenerife in the Canary Islands, is described and illustrated. This aquatic moss is primarily characterized by its irregularly bi- to unistratose laminae with scattered 3–4 stratose ridges and crests giving the leaf surface an uneven and rough appearance, the single but mostly forked and spurred costa, and the leaf margin with frequent polystratose limbidia of varying degrees of completeness. An assessment of the relationships of this new species is troublesome due to the sterile condition of the plants. Because of the structure of the leaf laminae, it is included in the genus Gradsteinia Ochyra which, so far, is known only from the Colombian Andes.     

potamolejeunea Holtii (Spruce) nov.comb.

Abstract

Bryophytes usually have anti-feeding properties to defend against microbial and herbivore attack; however, the consumption of Haplocladium microphyllum (Hedw.) Broth. capsules by Agrotis sp. larvae is rather common in Shanghai in the spring. To test whether H. microphyllum is the only moss eaten, and why the gametophytes of H. microphyllum are not eaten, a series of quantitative experiments were carried out to understand the feeding habits of Agrotis larvae on the given moss materials at three growth stages of larval life. The results show that the larvae can feed on the capsules of six moss species to different degrees: Funaria hygrometrica Hedw., H. microphyllum, Physcomitrium sphaericum (C.F.Ludw. ex Schkuhr) Brid., Trematodon longicollis Michx., Ditrichum pallidum (Hedw.) Hampe, and Pogonatum inflexum (Lindb.) Sande Lac. The capsules of the first four species were grazed heavily by the larvae, compared with limited consumption of the latter two (D. pallidum and P. inflexum), which even induced a high mortality rate among the larvae. With the growth of the larval instar, the daily demand for moss capsules by the larvae increases gradually. The lipid content of the capsules may play an important role when the larva selects its feeding target.     

Monograph of the moss genus Macrodictyum (Broth.) E.H.Hegew. (Dicranaceae)

Abstract

Macrodictyum is a small acrocarpous moss genus of three species (M. latifolium (E.B.Bartram) M.J.Price, M. proliferum (Mitt.) E.H.Hegew., M. wrightii (Sull.) E.H.Hegew.). It grows in tufts and mats on trees or rocks at 450–1500 m in the Neotropics. The genus has a restricted distribution within the Neotropics and is currently known from only a few localities in Cuba, the Dominican Republic, and southeastern Brazil. Macrodictyum is characterized by four main features: 1) appressed, non-crispate, ovate–oblong, lingulate to ligulate or linear leaves; 2) large, rhomboidal, thin-walled cells in the upper leaf; 3) large, irregular, multicellular apical teeth; and 4) guide cells that are ventral at and above mid-leaf. These features are atypical of the Dicranaceae. However, Macrodictyum shares pseudautoicous sexuality, sheathing perichaetial leaves, and peristome structure with the large pantropical Dicranaceous genus Holomitrium Brid. In these two genera the peristome consists of 16 single, triangular, entire or weakly divided, fenestrate, striate teeth that are papillose throughout on both the inner and outer surfaces. Macrodictyum is retained in the Dicranoideae (Dicranaceae), close to Holomitrium, based on its pseudautoicous sexuality, sheathing perichaetial leaves, and peristome structure.     

Polytrichum commune Hedw. and Polytrichadelphus magellanicus (Hedw.) Mitt. used as decorative material on New Zealand Maori cloaks

Abstract

Confirmation of the occurrence of the moss Ptychomnion densifolium on the main islands of New Zealand is provided and the features which separate it from the more common P. aciculare are outlined. A brief account of the history of P. densifolium in New Zealand is given and its morphology there is discussed. A key to the two species in New Zealand is provided and habitat differences between them outlined. New Zealand material differs from type locality (Tristan d' Acunha) material in having longer and more twisted acumens, and in this respect is similar to New Zealand material of P. aciculare. New Zealand populations of P. densifolium are recognisable in having stem leaves reflexed from an oblong sheathing base, and well developed basal leaf plications. It is a relatively widespread species in New Zealand, occurring in mostly upper elevation, open sites.     

Dicranodontium subporodictyon Broth. in Scotland

Abstract

The discovery in Scotland of a moss which has proved to be Dicranodontium subporodictyon Broth., hitherto only known in Asia, is announced.     

Reproductive traits in the tropical moss Octoblepharum albidum Hedw. differ between rainforest and coastal sites

Abstract

Octoblepharum albidum Hedw. is an autoicous moss commonly occurring in tropical savannas, dry forests, rainforests and coastal habitats. It frequently reproduces by spores and asexual structures (gemmae and protonemata or buds at leaf tips), making it a good model for understanding how reproductive traits change with respect to habitat type. Our aims were to characterize the different life-history traits in O. albidum relative to sexual and asexual cycles and to detect variations in reproductive performance among the different habitats, trade-offs among these traits, and relationships among reproductive traits and plant length. We studied colonies from two Atlantic rainforests and two coastal sites in north-eastern Brazil. Shoots in the coastal sites, compared to those of the forest sites, had higher numbers of sporophytes, male and female branches per shoot, male gametangia per sexual branch, and longer setae. Numbers of female gametangia per sexual branch did not differ between forest and coastal sites. A male-biased sex ratio of branches and gametangia occurred in all sites. Compared to gemmae, sporophytes and protonemata or buds were more likely to be found on longer shoots than on shorter ones, but this relationship was only applicable to forest sites. The abundant production of gemmae and protonemata or buds at leaf tips, and sporophytes (spores) in O. albidum are important components in explaining colonization success and maintenance in this tropical moss. Longer sporophytic setae in addition to a higher reproductive performance (especially for number of male gametangia and sporophytes per shoot) may favour spore dispersal and colonization in plants of coastal sites.     

Renauldia paradoxica Allen sp. nov. (Musci,Pterobryaceae)

Abstract

Renauldia paradoxica, a new Pterobryaceous moss from western Panama, differs from all other species of Renauldia by its long, narrowly acuminate leaves. This species fits somewhat uncomfortably in Renauldia and appears to occupy a position intermediate between Renauldia, Orthostichidium, and Pterobryopsis.     

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.     

Seasonal vartadoosln the nutrtent content of carpets of Acrocladium cuspidatum (Hedw.)Lindb.

Abstract

1. Seasonal variations in the percentaae of potassium, sodium, calcium and phosphorus in the current season's growth segment of Acrocladium cuspidatum at three different habitats are presented.

2. The results show that the nutrient content of the moss carpet varies with time of year and also between habitats. For this reason comparisons between the nutrient content of moss carpets from different habitats are unlikely to be valid unless made at the same time of year or during comparable stages in the annual growth cycle of the species concerned.

3. In conditions where the moss becomes inundated by natural waters having a high concentration of calcium ions, the moss accumulates calcium to abnormally high levels.

4. Comparison of the nutrient content of the moss on open downland and under scrub shows a greater accumulation of potassium in the moss carpet of the scrub habitat. The monthly differences between the potassium contents from the two sites are positively correlated with the monthly rainfall as are also the actual percentages of potassium present in the moss carpet beneath the scrub.     

Rapid photosynthetic recovery of a snow-covered feather moss and Peltigera lichen during sub-Arctic midwinter warming

Background: Arctic lichens and mosses are covered by snow for more than half the year and are generally considered as being dormant for most of this period. However, enhanced frequency of winter warming events due to climate change can cause increased disturbance of their protective subnivean environment.

Aim: To further understand cryptogamic responses to midwinter warming we compared the ecophysiological performance of one lichen and one moss species during a simulated warming event.

Methods: We measured photosynthesis and dark respiration in samples of the moss Hylocomium splendens and the lichen Peltigera aphthosa removed from under snow, and on natural refreezing after the warming event, which was simulated by using infrared heaters suspended above the ground.

Results: The moss exposed to light at +5 °C immediately after removal from their subnivean environment and from warmed plots showed positive net gas exchange within 332 s; the lichen required 1238 s. Photosynthesis and nitrogen fixation rates were equal to that, or higher than, during the preceding growing season. Upon refreezing after the event, moss photosynthesis declined considerably.

Conclusions: The moss, and to a lesser extent the lichen, may contribute to subnivean midwinter ecosystem respiration, and both are opportunistic, and can take advantage of warmer winter phases for photosynthesis and growth. This ought to be taken into account in vegetation change projections of cryptogam-rich ecosystems.     

Recent Bryological Literature, 62

Abstract

Fissidens gymnogynus Besch., F. mangarevensis Mont. and F. obscurirete Broth. et Par. are reported new to the Philippine moss flora. Their discoveries greatly strengthen the continental Asiatic affinity of the local moss flora.     

British Bryological Society Expedition to Mulanje Mountain,Malawi 3. Erpodiaceae (Musci)

Abstract

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