Rhizoidal Tubers Research Articles

Rhizoidal tuber production in a non-native, male-biased population of Gemmabryum klinggraeffii (Schimper) J.R.Spence & H.P.Ramsay

ABSTRACT Introduction. It is unusual to encounter male-biased populations of dioicous mosses. We report a case of a non-native (to the USA) dioicous moss, Gemmabryum klinggraeffii, in male-biased populations established through tuber recruitment from the soil propagule bank in an urban park in the context of an invasive plant removal experiment. Methods. The mosses in this study originated from soil samples taken from an urban park in the Midwestern USA. Within the park, soils were taken from plots that underwent invasive species removal and control plots that did not undergo species removal. Mosses emerging from the soil samples were propagated and grown for 1 year, after which the density of Gemmabryum klinggraeffii plants per pot and the mean numbers of tubers and gametophores were computed. Key results. Gemmabryum klinggraeffii was more likely to occur in soil from control sites where invasive species had not been removed. The number of tubers per stem was dependent on the abundance of G. klinggraeffii in the pot, such that pots with more G. klinggraeffii produced more tubers per stem on average. Plants with and without gametophores produced similar numbers of tubers, and the only sex organs detected in the populations were antheridia. Conclusions. Gemmabryum klinggraeffii depends on rhizoidal tubers that persist in soil propagule banks and are important to local population persistence in the urban park studied. Potentially other populations in North America are also male, single-sex populations that deserve further attention.

Pterygoneurum papillosum Oesau, a distinct moss species, its occurrence in southern England, new to Britain, and the presence of rhizoidal tubers

Pterygoneurum papillosum Oesau (Pottiaceae: Bryophyta) is reported from several widely scattered sites in southern England. These are the first reported occurrences outside Germany, although the species had already been collected at three of the English sites in the 1960s. The species is described and illustrated and its diagnostic characters are discussed. Its status as a distinct species is strongly supported by our observations. Rhizoidal tubers are reported for the first time in this species and in P. ovatum. The habitats of P. papillosum in England are described. It is a winter ephemeral of open calcareous soils that are seasonally moist.

<i>Didymodon rigidulus</i> var. <i>subulatus</i> (Thér. & Bartram ex E.B. Bartram) R.H. Zander, new to the moss flora of Mongolia and Asia

Not available. Bangladesh J. Plant Taxon. 22(1): 63–66, 2015 (June)

Pohlia lutescens (Mielichhoferiaceae, Bryophyta) in Russia

Pohlia lutescens, a species with rhizoidal tubers, is found in Russia for the first time. It was simultaneously revealed in several points in Perm Province (Northern Ural Mountains), and in single localities in Amurskaya Province and Khabarovsk Territory. Description and illustrations based on specimens from Russia are provided, ecology and distribution of the species are discussed.

A new species of Fissidens with remarkable rhizoidal tubers and gemmae from Macao, China

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.

Studies of protonemal morphogenesis in mosses. XI. Bryum and allied genera: a plethora of propagules

Asexual propagules found in the genus Bryum include rhizoidal and chloronemal tubers, axillary bulbils, chloronemal brood cells, and foliar and protonemal gemmae. While tubers and, to a lesser extent, axillary bulbils have been described in detail and used widely in the taxonomy of the genus, reports on the occurrence and morphology of protonemal gemmae are at best patchy, thus explaining their exclusion from any taxonomic and ecological evaluations of Bryum. Reported here is the first systematic survey of the occurrence of protonemal gemmae in 36 Bryum species and several related genera based on both wild and in vitro-grown specimens. Protonemal gemmae are described for the first time in 19 species; indeed the majority of Bryum species analysed produced protonemal gemmae in culture and subsequently these were also found in nature in many of the species. Compared with tubers (19 species) and bulbils (five species) protonemal gemmae (32 species) are the most ubiquitous asexual propagule in the genus. Overall gemma morphology within Bryum is fairly uniform: the gemmae are filamentous chloronemal derivatives and separate from the parent filament by the formation of a tmema (abscission) cell. Notable exceptions are the critically endangered B. schleicheri where clusters of apical choronemal branches detach by schizolysis and the highly branched gemmiferous protonemata of B. radiculosum which form from axillary rhizoids. While in the latter two species these unique gemma morphologies can be used for identification, overall protonemal gemmae are of much more limited use in Bryum taxonomy than rhizoidal tubers. Scanning electron microscopy, however, reveals that the protonemal gemmae in some species are highly ornamented, thus suggesting their possible future use in taxonomy alongside rhizoid papillosity. Although most of the genera allied to Bryum have vegetative propagules, very few produce protonemal gemmae. In those that do, only the gemmae of Mielichhoferia bryoides and Rhodobryum roseum have tmema cells and are remarkably similar to those of Bryum capillare and associated species. Gemma detachment in Epipterygium, Plagiomnium, Rhizomnium and Mnium is via schizolysis. Consideration of these gemma liberation mechanisms in relation to recent phylogenies of the Bryaceae suggests that schizolysis may be a synapomorphy for the Mniaceae. In vitro, gemma production is intrinsically linked to high nutrient availability in the substratum and there are indications that the same may also be true in nature. Ecologically, protonemal gemmae, presumably less long lived and less tolerant to desiccation than tubers, function in increasing the potential for initial establishment and localized spread of a given taxon, especially in situations where sporophytes are rarely produced.

Interactions between parasitic fungi and mosses: pegged and swollen-tipped rhizoids in Funaria and Bryum

Two kinds of parasitic fungal infections are described in the rhizoidal systems of both wild and cultured materials of Funaria hygrometrica, Bryum capillare and B. pseudotriquetrum. Protonemal and rhizoidal cells of Funaria produce pegs of host wall materialaroundsites of hyphal penetration. Similar structures appear to be much more widespread in hepatics and in Monoclea have been misinterpreted as rudimentary pegs, the characteristic feature ofpeggedrhizoids.Swollen side branch initials and the tip cells of major rhizoidal axescontaina single rozellopsidalean (Oomycota formerly Chytridiomycota) zoosporangium in Bryum pseudotriquetrum and up to three similar structures in B. capillare. Each zoosporangium produces a single exit tube. Whereas the infected cells die the subapical cells remain alive and,afterzoospore discharge, produce side branches whose tip cells also become infected. Restriction of the parasites to sidebranchinitials and rhizoid tip cells is perhaps because these are the only cells that the zoospores are able to penetrate. Nutrients translocated along rhizoids to sustaintipgrowth are diverted to nurture the fungi in infected plants. Differences between the number of zoosporangia per host cell and the number of exit tubes between different mosses suggest that more than one species of rozellopsidalean fungus may form rhizoid galls in mosses and not just Pleotracheluswildemanidescribedpreviously.Rhizoid galls appear to be genuinely uncommon in mosses but, following clarification of the differences between these and rhizoidal tubers, further discoveries may be anticipated.

Didymodon erosus sp. nov. (Musci, Pottiaceae) from the Iberian Peninsula

Didymodon erosus is described and illustrated as a new species from two localities in Spain (Iberian Peninsula), growing on calcareous rocks. It is characterized mainly by its markedly erose and papillose-crenulate in the upper middle leaf margins and rhizoidal tubers underground or on rhizoids in the lower part of the stem.

Studies of protonemal morphogenesis in mosses. IX. Discelium nudum: exquisite pioneer of unstable clay banks

The protonemal system of Discelium nudum produces a sward of unicellular, colourless, starch-filled rhizoidal tubers ca 1 cm below the surface of unstable clay banks. These short-lived and desiccation-intolerant diaspores are exposed on new clay surfaces following winter exfoliation of the original substratum. Their abundance and rapid germination appears to be a reproductive strategy giving Discelium a competitive advantage in this highly unstable habitat. The rounded, thin-walled, non-gemmiferous chloronemal filaments and colourless rhizoids of Discelium suggest affinities with the Funariaceae and the Gigaspermaceae. An early report of multicellular tubers in Discelium is most probably due to misinterpretion of the large starch grains, up to 20 μm in diameter, as cells within the unicellular tubers.

<p><strong>Occurrence of the neotropical moss <em>Dicranella hilariana </em>(Mont.) Mitt. in the Antarctic</strong></p>

Dicranella hilariana (Mont.) Mitt., a pan-neotropical moss species, is reported for the first time from the Antarctic botanical zone. It was found on geothermally heated ground near fumaroles on Visokoi, Candlemas and Bellingshausen Islands in the volcanic archipelago of the South Sandwich Islands. Dicranella recurvata Ochyra, Arts & Lewis-Smith, nom. nud., is reduced to synonymy with D. hilariana. The Antarctic plants of D. hilariana are briefly described and illustrated, including the rhizoidal tubers which have not previously been reported in this species. The global distribution of D. hilariana is briefly reviewed and mapped. It is suggested that the species reached the Antarctic via long-distance dispersal from South America by the prevailing strong westerly winds.

<strong>A contribution to the moss flora of Ecuador</strong>

An annotated list of new records or otherwise interesting species from Ecuador is presented. The occurrence of rhizoidal tubers is reported for the first time in Anoectangium aestivum, Brachymenium chilense and Bryoerythrophyllum campylocarpum.

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

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.

Bryum stellituber sp. nov., a new species of the Bryum erythrocarpum complex from India

Bryum stellituber Arts sp. nov. is described from India. The plant belongs to the Bryum erythrocarpum complex, characterised by the occurrence of red star-shaped rhizoidal tubers with conical projecting outer cells. It was collected in a terrestrial moss community with Bryum sauteri B.,S.&G. and Dicranella staphylina Whiteh. The latter two are first records for India.

The genusSplachnobryumin Africa, with new combinations inBryumandGymnostomiella

A revision of the African species of Splachnobryum is presented. Only three species are accepted, viz. S. aquaticum C. Müll., S. gracile Besch. and S. obtusum (Brid.) C. Müll. The species are illustrated and .described. The occurrence of rhizoidal tubers in S. obtusum is reported. S. acutifolium Thér. is placed in Bryum. S. erosulum C. Müll. ex Dus. and S. tenerum C. Müll. ex Dus. are placed in Gymnostomiella. Seven other African Splachnobryum species and two varieties are reduced to synonomy with S. obtusum or S. gracile.

Pohlia integra(Card.) Shaw a neglected species, recorded from southern Africa and South America

Mniobryum bracteatum Bartr. from Ecuador is reduced to a synonym of Pohlia integra (Card.) Shaw, previously known only from Mexico. The species, characterized by the occurrence of rhizoidal tubers, is also recorded from Bolivia and southern Africa.

Rhizoidal tubers and protonemal gemmae in EuropeanDitrichumspecies

AbstractThe occurrence of rhizoidal tubers and protonemal gemmae in European Ditrichum species is described in plants collected in nature and compared with protonemal gemmae and tubers obtained in agar culture. Rhizoidal tubers are reported for the first time in D. pallidum, D. plumbicola, D. subulatum and D. zonatum and earlier reports on tubers in D. cylindricum, D. cornubicum, D. heteromallum, D. lineare and D. pusillum confirmed. Based on the occurrence and morphology of tubers, the European species of Ditrichum may be subdivided into four groups.

Rhizoidal tubers inArchidium indicumandA. yunnanensesp. nov., a new moss from China

Abstract Archidium yunnanense sp. nov. from China is described and illustrated. Its differences from the related species A. elatum Dix. & Sainsb., A. indicum Hampe & C. Mull. and A. subulatum are outlined. Rhizoidal tubers are reported in A. indicum and A. yunnanense.

Bryum demaretianum sp. nov.,a new species of theB. erythrocarpumcomplex from Belgium

Bryum demaretianum Arts sp. nov. is described from Belgium. The plant belongs to the B. erythrocarpum complex and is characterized by the occurrence of dense clusters of bright orange pyriform rhizoidal tubers.

The occurrece of rhizoidal tubers in two species of the family Ditrichaceae

The occurrece of rhizoidal tubers in two species of the family Ditrichaceae

Rhizoidal tubers of Ditrichum heteromallum in Japanese population

Rhizoidal tubers of Ditrichum heteromallum in Japanese population