The sporelings of Lejeunea caespitosa Lindenb.

Abstract

Sporelings of Lejeunea caespitosa Lindenb. usually form a primary protonema of a single row of four cells, and a secondary protonema at first of two rows, and eventually of four rows of cells. The juvenile stem with two dorsal and three ventral rows of cells produces simple undivided underleaves and elobulate primary leaves or, later, lobulate juvenile leaves of which well developed lobules nearly equal the lobes in size. Bifid underleaves are formed as soon as the stem acquires four ventral rows of cells.     

An Annotated List of British Hepatica

Abstract

Archidium minutissimum sp. nov., a minute ephemeral species with persistent protonema and red-brown bract-like leaves, is fully described and illustrated.     

The sporeling development in Frullania tamarisci (L.) Dum

Abstract

The sporeling development in Frullania tamarisici (L.) Dum. ssp. tamarisci is described for the first time. Its pattern belongs to the Frullania-type in which a globose, many-celled protonema is formed within the stretched exospore. The primary leaves are ovate to oblong, followed by the saccate-inflated juvenile leaves. In the juvenile stage each underleaf is associated with a single leaf.     

Cation contents of acrocarpous and pleurocarpous mosses growing on a strontium-rich substratum

Abstract

A new species, Nanobryum thorsbornei, is described from northern Queensland, Australia, and compared with N. dummeri, an African species to which it seems most closely allied. They both have a remarkable persistent protonema which is partly pseudothallose but the leaves of the Australian species are trilobate, a feature lacking in the African species. The relationship of Nanabryum with Fissidens, particularly F. gladiolus, is discussed.     

Scapania mucronata Buch in Scotland

Abstract

Regeneration from detached leaves at 20°C in 12 h days was studied in six species. Of the four species of Polytrichum and two of Pogonatum studied, only Pogonatum aloides did not regenerate from leaves. This result could be related to the fact that in nature only this species possesses persistent primary protonemata. Polytrichum commune, P. formosum and P. juniperinum developed long, muchbranched secondary protonemata which produced buds at intervals. Pogonatum urnigerum developed buds without an initial protonema, and Polytrichum piliferum short, unbranched protonemal threads, each bearing a single terminal bud. In all cases regenerants arose from either the large cells at the bases of lamellae, or less often, basal cells of the lamellae themselves. In Pogonatum urnigerum the amount of regeneration tended to decrease from apex to base of leaf, while in the Polytrichum species the reverse occurred. No definite conclusions could be drawn with regard to the effect, if any, of leaf age on regeneration. Possibly the temperature experienced beforehand or some other seasonal factor, affects regeneration, but the question needs further investigation.     

Archidium thalliferum sp. nov. with a persistent cushion-shaped protonema unique in Musci

Abstract

Archidium thalliferum possesses a highly specialized persistent cushion-shaped protonema which is unique in Musci. The thalloid structure is pseudoparenchymatous and differentiated into layers with protective, photosynthetic and possibly storage functions.     

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.     

The relationship between Mittenia plumula (Mitt.) Lindb. and Schistostega pennata (Hedw.) Web. & Mohr

Abstract

In spite of the absence of a peristome in Schistostega, developmental studies show that the internal structure of the capsule has considerable similarity and presents no strong barriers to a relationship with Mittenia. This is strongly supported by the protonema and many features of the gametophore and sporophyte. Therefore it is suggested that the Mitteniaceae be transferred from the Bryales to the Schistostegales.     

A Note on Acrocladium trifarium (W. & M.) Richards & Wallace in Ireland

Abstract

Chains of 3–4-celled gemmae have been observed on the protonema of Trematodon brevicalyx, both in nature as well as in cultures. They are produced in abundance and may help in its survival, propagation and wide dispersal.     

Inter-population variation in morphology and physiology in the cosmopolitan moss Bryum argenteum Hedw.

Abstract

Aspects of the morphology and temperature relations of clones isolated from temperate, tropical and polar populations of Bryum argenteum are compared. The clones were similar in their responses to frost and to high temperature stress, and a day/night temperature regime of 22/15°C in each case proved the most favourable of those tested for protonema growth and shoot production. Antarctic and tropical provenances both showed slow protonema growth and shoot production at 5/–5°C. Antarctic clones were in general the most vigorous of those tested in a range of environments.

The clones proved morphologically distinct from each other in collateral cultivation, differing in protonema morphology, shoot arrangement and leaf morphology. There was correlation between variation in the cultures and in the original field populations in some characters such as length of the leaf apiculus but other differences between the field populations, notably in stem length, leaf length and nerve excurrence, were not maintained in cultivation.     

Germination of the Spores and Development of Primary and Secondary Protonema of Funaria hygrometrica

Abstract

1. The primary protonema of Funaria hygrometrica, cultivated on Knop's or Marchal's agar in the light, proved to consist of filaments with much chlorophyll, a hyaline membrane, perpendicular cross-walls and branches equal to the main filament (chloronema). These filaments grow on the surface of the agar, the branches may also grow vertically. Sometimes filaments with less chlorophyll occur immediately after the germination. The caulonema described by Sironval has not been observed. Thus the rhizoid-like forms mentioned in the literature should more likely be considered as a result of external conditions (see Schoene, Bauer, Heitz and Fitting). Therefore it remains doubtful if a distinction between rhizoids and chloronema on the primary protonema is of any importance as it is impossible to give a good definition of either form.

At the base of moss plants main filaments with brown membranes, oblique septa and without chlorophyll may develop (rhizoids). They grow on the surface or within the agar. In F. hygrometrica especially, the stem seems to influence the occurrence of these rhizoids. The main filaments form buds on the basal cell of the branches and thus serve for vegetative reproduction. The branches show the characteristics of the chloronema. This is contrary to the conclusion of Westerdijk that rhizoids would pass into chloronema only when they are damaged or when the growth of the end bud of the plant is inhibited. At the base of the plant, moreover, little ramified, short branches with oblique septa appear which do not produce buds.

2. Branches may develop in the first growth stages of the primary protonema at any point of the cells. One single cell of a main filament can produce none, one, or more than one branch. Later the branches appear immediately behind the acroscopic cross-wall except in a few cases. Each cell then produces one branch.

3. Buds always develop at the basal cell of a primary branch of a green main filament or of a rhizoid derived from a moss plant.

4. In two ways the protonema may fall into pieces, which can develop into new main filaments:

(a) By forming brood cells; rounded cells which get detached by splitting of the septum. This phenomenon is very frequent. Contrary to Servettaz's opinion it seems to occur particularly under unfavourable conditions.

(b) By forming special cells, tmemata, whose walls are rent. These occur on the primary protonema contrary to the observations of Correns and Bauer, but they are much less frequent than the brood cells. No observations have been made on the circumstances of their occurrence.     

Notes on the Taxonomy of the Genus Philonotis by means of Vegetative Characters

Abstract

Three cytokinins tested, BAP, 2iP and kinetin at concentrations of 10^?8 – 10^?4 M, induced buds on Jhe protonema of Bryum pallescens, which otherwise remains bud-free on basal medium in ordinary cultural conditions. BAP proved best for bud induction, and was followed in effectiveness by 2iP and kinetin. Protonemal growth decreased with increase in concentrations of BAP, but with 2iP and kinetin it increased only with increase in concentration up to 10^?5 M.     

Three modes of asexual reproduction in the moss Octoblepharum albidum

Abstract

Populations of Octoblepharum albidum growing in very moist and shaded habitats were found to have three kinds of asexual reproduction. First, the production of foliar gemmae along the upper half of leaf margins. Second, the production of protonema gemmae on protonemata originated from foliar gemmae. Third, the production of buds and new shoots at leaf tips. The formation of new shoots is further repeated at the leaf tips of the new shoots, giving the plant the character of a 'walking moss'.     

Morphology and life history of Coelocladia arctica (Dictyosiphonales,Phaeophyceae), new to Japan*

The occurrence of Coelocladia arctica Rosenvinge (Dictyosiphonales, Phaeophyceae) is reported for the first time in the Pacific Ocean, from Oshoro, Hokkaido, Japan. The field material was approximately 30 mm in height, up to 300 M-μn in diameter, 2-3 times irregularly branched and provided with phaeophycean hairs and plurilocular sporangia. The thallus was composed of several (usually four) large, hyaline, rounded, isodiametric inner cells, with smaller sub-cortical and pigmented cortical cells. The plurilocular sporangia were 3-4 celled, often branched, and protruded from the cortical cells, arranged in a crown-shaped complex. In culture, the plurispores germinated unipolarly leaving an emptied original spore wall, and developed into a branched protonema. Cells of the protonema as well as the erect thallus contained several disc-shaped chloroplasts with pyrenoids. Uniseriate erect filaments arose from the protonema, then became polystichous and formed branches. Unilocular sporangia were never observed in the field or in cultured material. Erect thalli were formed under culture conditions of 5-15°C, and developed a thick parenchyma at 5-10°C, irrespective of the day length.     

Evaluation ofMicrothrix inconspicuella, [Lepidoptera: Pyralidae], a potential biological control agent forEmex australis in Australia,carried out in apple orchards in South Africa

Host specificity tests carried out in the laboratory in Australia during 1977, showed thatMicrothrix inconspicuella Ragonot could develop on young apple leaves (Harley et al., 1979). Field studies in unsprayed apple orchards in South Africa showed that some feeding occurred, but fewer than 40% of late instar larvae developed to adults when confined in sleeves on apple tree branches. No feeding or survival occurred in large field cages or in the open. Adults which developed from apple fed larvae were smaller, deformed, occasionally mated and laid fertile eggs but their progeny did not feed or develop on apple fruit or leaves. In conclusion,M. inconspicuella larvae did not develop on apple fruit or leaves in the field, damage was mainly limited to apples already injured and feeding on leaves was minimal. Under normal pest control practicesM. inconspicuella populations did not survive on any part of the apple tree or onE. australis growing under the trees.      

Hymenostylium xerophilum,sp. nov., and H. gracillimum,comb. nov., two neglected European mosses and their molecular affinities

Abstract

Hymenostylium xerophilum is described as a new species from the European Alps. Molecular rps4 and ITS data support its recognition and elucidate its affinities to other species of the tribe Pleuroweisieae. It is closely related to H. gracillimum, comb. nov., which is based on the old and neglected Gymnostomum gracillimum, which replaces the recent name G. boreale. Both species share non-coloured to pale yellowish-brown rhizoids, stem central strand and indistinct sclerodermis, keeled leaves, and concave laminae in abaxial view. They differ from each other in leaf shape and several essentially quantitative characters. Sporophytes have never been found in H. xerophilum, but they are known from several localities in H. gracillimum. The former colonizes rather dry, sunny to half-shaded calcareous rocks, whereas the latter needs moist and shaded rock habitats and shows a preference for subneutral slate. At present, H. xerophilum is known only from the Alps (Austria, and a single site in Germany), where it is rather widespread in calcareous regions. H. gracillimum seems to be a distinctly rarer plant, to date known only from eight Austrian sites and one locality in Russian Karelia. Other published records under the name G. boreale have been wrongly attributed to this species. Lectotypes are designated for G. gracillimum and Gyroweisia acutifolia. A key to Hymenostylium and the genera of Pleuroweisieae in Europe is presented.

Thicker rhizoids of both species are covered with a thick, non-coloured protective layer and filled with oil-droplets and leucoplasts. They represent a subterranean secondary protonema, which plays an important role in the survival and propagation of these mosses, vital especially in the case of the non-sporulating H. xerophilum.     

SPORE GERMINATION AND EARLY DEVELOPMENT OF THE GAMETOPHYTE OF SCHIZAEA PUSILLA

During germination of the spore of Schizaea pusilla, the first division of the protoplast was perpendicular to the polar axis and resulted in the formation of the rhizoid. The next division parallel to the polar axis of the spore gave rise to the protonemal initial. Following this “Vittaria”-type germination, the protonema that developed was characterized by an extensive branching to produce uniseriate filaments and rhizoidophores.     

Physiological,biochemical, and fluorescence parameters of senescing sugar beet leaves in the vegetative phase of growth

The phase of vegetative growth of sugar beet (Beta vulgaris L., single-sprout form) was conditionally subdivided into four periods according to leaf number and size (including already withered leaves): (A) 8 ± 1 weeks after seedling emergence (wase) (5–7 leaves); (B) 11 ± 1 wase (10–12 leaves); (C) 14 wase (13–15 leaves); (D) 15 wase (15–18 leaves). It took each next leaf about 1 week to come into view. In the course of leaf senescence, palisade parenchyma became less ordered; cells, vacuoles, and intercellular spaces expanded; leaf area and thickness increased. Chloroplasts became swollen, starch grains (and later osmiophilic globules) accumulated and degraded. In every growth period, the highest levels of soluble carbohydrates (sCH), chlorophyll (Chl (a + b)), soluble protein, and the highest activities of rubisco and soluble carboanhydrase usually preceded the full leaf expansion. In unfolded leaves at the growth period B, the maximum values of biochemical characteristics were as a rule higher than at the growth periods A and C and especially D. The only exception was Chl (a + b) with its peak level somewhat increased with plant age. Occurrence of peak values of individual characteristics depended on plant growth period. These characteristics started diminishing asynchronously, with a minimum in old operational leaves. Only the sCH content in the leaves at the periods C and D was stable. Changes in quantum yield at PSII and nonphotochemical fluorescence quenching reflected the age-associated differences in biochemical characteristics. The results are discussed in the light of the idea that leaf senescence is a normal stage of development directly related to the changes in source-sink relations. Biochemically, this stage comprises the degradation of temporarily stored products and partial utilization of the breakdown products for maintenance of the growth of newly formed leaves and root.     

梨蒴珠藓孢子萌发与原丝体发育特征研究

为了解梨蒴珠藓（Bartramia pomiformis）孢子萌发和原丝体发育特征,在显微镜下观察室内人工培养的梨蒴珠藓单倍配子体发育过程。结果表明,梨蒴珠藓孢子吸水膨胀5 d后,开始破壁萌发,原丝体系统以丝状绿丝体为主,轴丝体在绿丝体上分化产生。培养22 d后,配子体在轴丝体细胞上分化产生。参照Nishida的标准,梨蒴珠藓孢子萌发类型为真藓型（Bryum-type）。这为梨蒴珠藓的人工扩繁提供了发育学基础资料。