Studies on Antipodal Hepaticae: II. Archeophylla Schuster and Archeochaete Schuster,New Genera of Blepharostomaceae

Abstract

The two genera Archeophylla Schust. and Archeochaete Schust., briefly diagnosed in a key to antipodal Hepaticae (Schuster, 1963 b), are described in detail; for the fint genus a second, new species is described. Archeophylla differs from other genera assigned to the Blepbarostomaceae in broadly unispiral elaters and the development of conspicuous trigones of the leaf cells. Archeochaete shows a series of synthetic features, such as a contracted perianth mouth and quadrifid bracts that lack armed margins, suggestive of Lophochaete Schust.; other features of the genus strongly suggest Temnoma Mitt., e.g. the non-bisbifid leaves and the tendency for smaller underleaves. This last genus was recently erroneously assigned to the Trichocoleaceae by Fulford (1963).

The discovery of these genera strongly indicates that the Blepharostomaceae must be broadly delimited; hence the families Pseudolepicoleaceae and Herzogiariaceae are placed in synonymy. Chaetocolea Spruce is also shown to belong probably to the Blepharostomaccae, in which case the Chaetocoleaceae would also have to be relegated to synonymy.     

Die Namen der Familien und Unterfamilien der Lebermoose (Hepaticopsida)

Abstract

Part I deals briefly with the application of the Code rules to family and subfamily names.

In Part II full references are given for all family and subfamily names of Hepaticopsida, some with nomenclatural or taxonomic notes added. There are three lists, each in alphabetical order: A. legitimate names (78 f., 62 subf.), B. illegitimate names (21 f., 10 subf.), and C. invalid names (only those derived from generic names; 17 f., 11 subf.); in total 116 family and 83 subfamily names. Five family names (Choneoleaceae Schust., Conocephalaceae K. Müll., Exormothecaceae K. Müll., Oxymitraceae K. Müll., Perssoniellaceae Schust.) and three subfamily names (Allisonioideae Schust., Cololejeuneoideae Herz., Odontosehismatoideae Buch) are validated by Latin diagnosis. Five subfamily names (Hygrobielloideae (Joerg.) Schust., Isotaehidoideae (Hatch.) Grolle, Makinooideae (Nakai) Grolle, Mastigophoroideae (Nees) Grolle, Pallavicinioideae (Migula) (Grolle) are proposed by change of rank, whereas five other subfamily names (Acromastigoideae Grolle, Blepharostomatoideae Grolle, Cyathodioideae Grolle, Lethocoleoideae Grolle, Notothyladoideae Grolle) are newly proposed.

Part III is a taxonomic arrangement of the hepatic families and subfamilies. For each of the five orders of Hepaticopsida the accepted families (sixty-two in total) are listed alphabetically with full synonymy : Anthocerotales (1), Marchantiales (16), Metzgeriales (8), Calobryales (2), Jungermanniales (35). The accepted subfamilies with their synonyms are added to each family.     

Austral Hepaticae,IV. Notes on Lophozia subgenus Protoloplzozia Schust., with diagnosis of a new South American species

Abstract

The distinguishing features of Lophozia subg. Protolophozia are enumerated. A key is provided for the eleven species of this primarily cool antipodal and subantarctic subgenus. Lophozia gymnocoleopsis Schust. & Engel from southern Chile is described as new. This species and L. crispata, also of southern South America, are the only representatives of subg. Protolophozia in South America. Protolophozia sect. Notolophozia and sect. Gymnocoleopsis Schust. are described as new.     

Squash Techniques in the Cytological Investigation of Mosses

Abstract

Photosynthetic activity of attached sporophytes is very low (a few per cent or less) compared with that of associated gametophyte structures (perianth, bracts and uppermost leaves) in Cephalozia bicuspidata and Lophocolea heterophylla, or with even small areas of thallus in Pellia epiphylla. Photosynthetic uptake of ¹⁴CO₂ by developing sporophytes of P. epiphylla, C. bicuspidata and L. heterophylla is at most a few per cent of the ¹⁴C translocated subsequently from the gametophyte, and could be negligible. In L. heterophylla, the perianth, bracts and uppermost leaves appear to play only a limited role in nutrition of the sporophyte, the leafy shoots making a major contribution. In C. bicuspidata the perianth and leaves of the short archegonial shoot may provide a substantial part of the nutrition of the sporophyte. There is some indication in all three species that translocation from the gametophyte is most active when the sporophyte reaches full size but is still green, declining in the final stages of maturation of the capsule.     

Distribution Maps of Bryophytes in Britain

Abstract

The following species of Cheilolejeunea subgen. Strepsilejeunea are recognised from Africa and described: C. krakakammae (Lindenb.) Schust., C. pluriplicata (Pears.) Schust., C. usambarana (Steph.) Grolle, C. convexa S. Arn., C. pocsii E. Jones, sp. nov., C. camerunensis S. Arn. Strepsilejeunea georgensis S. Arn. is a synonym of C. krakakammae.     

Evolution de la structure plastidiale et des reserves polysaccharidiques au cours de la déshydratation des gamétophytes feuillés du Polytrichum formosum Hedw. (Polytrichales)

Abstract

The effects of a 24 h dehydration period on plastid ultrastructure and their starch content have been studied on the leafy gametophyte of a poikilohydrous moss Polytrichum formosum Hedw. It has been shown that desiccation induces a swift resorption of the starch grains in the plastids of the meristematic cells of the shoot apex without any major disorganisation of the thylakoids. However starch grains are preserved in the dehydrated tissues of the adult leaves. The starch hydrolysis is continued with a marked increase of the sucrose concentration to this may be attributed an osmoregulatory role in the first stages of the water loss. Upon rehydration the plastid ultrastructure is entirely restored with new starch inclusions appearing in less than 4 h.     

Pollen germination in Welwitschia mirabilis Hook. f.: differences between the polyplicate pollen producing genera of the Gnetales

Pollen grains of the seed plant genera Ephedra L. and Welwitschia Hook. f. (Gnetales) are of similar size, shape, and have a polyplicate exine with alternating thicker and thinner regions. Ephedra pollen is considered inaperturate and the exine is shed during germination, leaving the male gametophyte naked. The shed exine curls up and forms a characteristic structure with transverse striations. Such upcurled exines have been found in situ in Early Cretaceous seeds with affinities to Ephedra. The purpose of this study was to document the germination of Welwitschia pollen and investigate whether they also discard their exine during this process.

The pollen grains of Welwitschia are monoaperturate with a distinct, distal sulcus. During germination, the sulcus splits open and the gametophyte expands to a spherical form that extends out of the exine. The pollen tube starts to grow one or two hours later and as in Ephedra, it is displaced towards one side. The exine is not shed but remains as a “cap” that partly covers the male gametophyte. Thus, in this respect the germination process is distinctly different from that in Ephedra and this study demonstrates that discharging the exine during pollen germination is unique to Ephedra, among the polyplicate pollen producing genera in the Gnetales.     

Eine neue Taxilejeunea aus Madagaskar und Réunion

Abstract

Taxilejeunea furcicornuta sp.nov. from Madagascar and Réunion is described and figured in detail. Its affinities to T. conformis (Nees & Mont.) Steph. and Stenolejeunea Schust. are briefly discussed.     

Ricerche Embriologiche su Senecio Vulgaris L. var. Thyrrenus Fiori

Abstract

Embryological researches on SENECIO VULGARIS L. var. THYRRENUS Fiori. — Male gametophyte, development of tapetal cells and female gametophyte have been studied in Senecio vulgaris L. var thyrrenus Fiori.

1) The development of male gametophyte is normal. Divisions of the microspore mother cells are of the simultaneous type. The division of the generative nucleus has never been observed till the pollen grain was in the anther.

2) The tapetal cells follow a very simple development. The nucleus of each cell divides only twice starting at the same time with the meiotic divisions of pollen mother cells but ending much earlier; subsequently, as usually happens with the Asteraceae, the ameboid involution of the tapetum begins. Endomitosis or any other process which leads to a polyploidy not due to nuclear fusion, has never been observed.

3) The female gametophyte is eight nucleate of the normal type (Polygonum). At maturity it shows only three antipodal cells whose nucleus undergoes at first, two or three divisions. Only later these new nuclei, always within the antipodal cell, may fuse in a polyvalent one.     

Demographic population structure of a leafy epixylic hepatic Anastrophyllum hellerianum (Nees ex Lindenb.) R.M.Schust

Understanding the population processes is central when assessing proper conservation acts, especially in the case of species which inhabit temporal and patchy substrates, such as decaying wood. In epixylic bryophytes, however, only little is known of the demographic population structure and within-population dynamics. In this study on a leafy epixylic hepatic, Anastrophyllum hellerianum (Nees ex Lindenb.) R.M.Schust., a set of demographic traits is investigated, including colony area and size, proportions of the sterile, gemmiparous or sexual developmental stages, the shoot size class distribution among the developmental stages, and numbers of asexual propagules present on the shoots. The estimates of mortality are assessed on the basis of the proportions of dead shoots found in the colonies. The size distribution within the developmental stages of this species shows that a certain threshold size is required for both asexual and sexual reproduction. The shoot size is negatively correlated with density, whereas the numbers of asexual gemmae and the proportions of developmental stages are not affected by shoot density. Furthermore, provisional estimates are calculated for the transitions from early developmental stages to reproductively mature stages. The results indicate that the initial phases of the gametophyte development are the most vulnerable.     

Morphological adaptation to water uptake and transport in the poikilohydric moss Tortula ruralis

Abstract

In this paper different water-holding and transport adaptations to face the uneven and intermittent distribution of water in the ectohydric moss Tortula ruralis are referred to.

The external conduction of water is operated by different and efficient systems (spaces between adjacent shoots, between leaves, leaves and stems, leaves and rhizoids, life form, etc.) which facilitate absorption and transport of solutions.

Also epi-organ capillary systems (bases and revoluted margin of leaves, a groove, a close network of capillary channels determined by the papillae), intra-organ capillary systems (hyalocysts) and certain amount of internal conduction (conducting parenchyma, stereoma) co-operante to absorb and distribute water to the whole gametophyte.

In addition, some adaptations to xerophytism and heliophytism (life form, disposition of phylloids, hair-points) are discussed.     

A mixed stand of Sphagnum subsecundum var. auriculalum and var. inundatum in North Wales

Abstract

Schusterolejeunea nom. nov. is proposed to replace the mono typic Cladocolea Schust. 1963, non van Tieghem 1895. Sch. inundata (Spruce) comb. nov. (≡ Lejeunea inundata Spruce) is lectotypified and Potamolejeunea sprucei Steph. newly placed in its synonymy.     

Systematics value of stomata in some Nigerian hardwood species of Fabaceae

ABSTRACT

Epidermal morphology, and the structure and development of stomata in 10 species of Fabaceae are described. The epidermal cells varied from irregular to straight-walled and in some taxa sinuous patterns were observed. The leaves are hypostomatic. Anomocytic stomata follow an agenous ontogenetic pathway, while paracytic stomata are eumesogenously derived. These stomatal features are considered to be of systematic value in delimiting hardwood species in this family.     

Two new species of Lejeunea Lib. (Hepaticae: Lejeuneaceae) from Sikkim,India

Abstract

Two new species of Lejeunea Lib., L. kashyapii sp. nov. and L. mehrana sp. nov. are described from Sikkim, India. The former is characterized by sub-orbicular leaves; first tooth of leaf lobule, 1–3 cells long 1–2 cells wide at base; reniform underleaves slightly wider than long; monoicous sexuality; 2–3-paired male bracts; obcordate perianth with 4–5 smooth keels (2 lateral, auriculate; 2 ventral; 0–1 dorsal, indistinct). Whereas, the latter is characterized by oblong – ovate leaves; lobule 1/6–1/5 as long as lobe; distant – contiguous underleaves with 1–3 teeth on each lobe; dioicous (?) sexuality; 2–4-paired male bracts and 1–2 male bracteoles present near the base of androecia. A key to the Indian species of the genus are provided.     

The Arabidopsis SKP1-like genes present a spectrum of expression profiles

The yeast Skp1 protein is a component of the SCF complex, an E3 enzyme involved in the specific protein degradation pathway via ubiquitination. Skp1 binds to F-box proteins to trigger specific recognition of proteins targeted for degradation. SKP1-like genes have been found in a variety of eukaryotes including yeast, man, Caenorhabditis elegans and Arabidopsis thaliana. The Arabidopsis genome contains 20 SKP1-like genes called ASK (for Arabidopsis SKP1-like), among which only ASK1 has been characterized in detail. The analysis of the expression pattern of the ASK genes in Arabidopsis should provide key information for the understanding of the biological role of this family in protein degradation and in different cellular mechanisms. In this paper, we describe the expression profiles of 19 ASK promoter-GUS fusions in stable transformants of Arabidopsis, with a special emphasis on floral organ development. Four ASK promoters did not show any detectable expression in either inflorescences or seedlings. Our results on the ASK1 expression profile are consistent with previous reports. Several ASK promoters show clear tissue-specific expression (for instance in the connective of anthers or in the embryo). We also found that almost half (9/19) of ASK promoters direct a post-meiotic expression in the male gametophyte. Tight regulation of the expression of this gene family indicates a crucial role of the ubiquitin degradation pathway during development, particularly during male gametophyte development.     

A new Cheilolejeunea Marchantiopsida: Lejeuneaceae from montane forests in New Zealand

Abstract

Cheilolejeunea celata M.Renner & Glenny sp. nov., a minute species from high elevation (generally >600 m), high rainfall forests on the wetter, western side of New Zealand, is described and illustrated. It is similar to Cheilolejeunea novaezelandiae R.M. Schust. in its dome-shaped papillae on the lobe surface and its autoicous state, but differs in bearing papillae over the entire lobe surface and on the underleaves, in having narrower underleaves that are never imbricate and have a narrow sinus, and in growing primarily in forest, on the stems of other bryophyte species. In its combination of oblique lobes, strongly inflated keel, and bifid underleaves, the species provides further support for the recent merger of Cyrtolejeunea into Cheilolejeunea.     

Morphological and phytochemical studies of Plagiochila papillifolia Steph., a Neotropical liverwort new to Europe

Abstract

The Neotropical liverwort Plagiochila papillifolia Steph. is conspecific with P. caespiticia Spruce ex Herzog (nom. inval.), P . deciduifolia Steph., P . solmsii Steph. and P . verruculosa R.M.Schust.; it is reported from the Azores, new to Europe. Morphologically it shows affinity with sect. Bidentes Carl; phytochemically, several of its lipophilic secondary metabolites are the same as those of P . retrorsa Gottsche, another Neotropical species reported only recently from Macaronesia.     

Sull'embriologia di Leontopodium Nivale (Ten.) Huet ex Hand. Mazz.

Abstract

Embryology of « Leontopodium nivale » (Ten.) Huet ex Hand.-Mazz. — As in « Leontopodium alpinum » Cass. var. a typicum Fiori e Paoletti, from different alpine localities, no cases of apomixis have been observed (Maugini 1962) while Sokolowska-Kulczycka (1959) has noticed this phenomenon in the same species collected on the Tatra mountains, an embryological research on « Leontopodium nivale » (Ten.) Huet ex Hand. Mazz. has been undertaken. The material, collected in the alpine garden of Campo Imperatore (Abruzzo), has shown that the development of the female gametophyte occurs as in Leontopodium alpinum, according to the normal monomegasporial type which leads to the formation of an 8-nucleate gametophyte which at maturity is almost always poliantipodate. In « Leontopodium nivale » there is no trace of apomixix, but many cases of degeneration, particularly in the mature gametophyte, have been observed.     

Austral Hepaticae. XXI. Paracromastigum fiordlandiae (sp. nov.) and the delimitation of Paracromastigum and Hyalolepidozia (Lepidoziaceae)

Paracromastigum fiordlandiae Schust. & Engel from New Zealand is described. It approachesHyalolepidozia in the almost uniformly intercalary branching but differs from it in the intermingled 2–3-lobed leaves and the stem with 9–12 rows of cortical cells.Paracromastigum andHyalolepidozia are intimately allied toPseudocephalozia Schust., and one could argue that they could all be placed as subgeneric elements in a single genus. Whatever their status, these taxa fit reasonably well into Lepidoziacaae subfam. Zoopsidoideae.