Morphologie und Biologie der Algen

Oltmanns, Friedrich

doi:10.5962/bhl.title.44469

Cited by 246 publications

(40 citation statements)

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“…In agreement with several other writers (Oltmanns, 1922;Janet, 1914;Kniep, 1928; Smith, 1938a;Chadefaud, 1952;) I consider this a distinct somatic phase and a sporophyte. The carposporophyte develops from the zygote and its main function is spore formation.…”

Section: ( D ) the Carposporophyte Of The Florideaesupporting

confidence: 88%

Life Histories in the Algae With Special Reference to the Chlorophyta, Phaeophyta and Rhodophyta

Drew

1955

Biological Reviews

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SUMMARY The general essays on this subject which have appeared during the past two or three decades have dealt in the main with types of life history based on the nuclear phases, all algae being classed together. Speculation about the phylogenetical relationship of these types has occupied a prominent place. The aims of this article are somewhat different and are as follows: to consider what is meant by the life history of an alga, to interpret certain characteristic morphological phases present in some life histories, to classify types of life histories recognizable in Chlorophyta, Phaeophyta and Rhodophyta separately, using primarily somatic phases, to indicate the extent of our knowledge. Life history is denned as the recurring sequence of somatic and nuclear phases characteristic of the species under consideration. A life history of an alga should therefore give the reader a comprehensive account of the main features of the succeeding phases of growth and reproduction from a given stage, such as the zygote, until a similar stage is next reached, together with cytological information regarding the place of syngamy and meiosis. In interpreting life histories three considerations are kept in mind: the growth and development of the whole organism, the relation of the organism to its environment, the origin of the more highly specialized life histories which have arisen from the simpler types. The terminology used has been selected carefully to give freedom of thought and to avoid prejudging the interpretation. A nuclear phase is denned as that state of an organism characterized by mitotic divisions all showing the same chromosome number. It then follows that some life histories are monophasic, some diphasic, and so on. Monophasic life histories include haplonts and diplonts, and diphasic life histories diplohaplonts. Derivatives from, and elaboration of, diplohaplonts and their evolutionary significance are considered. A somatic phase is denned as a state of an organism recognizable by a characteristic morphological appearance independent of its chromosome number. Depending on the number of somatic phases recognizable, the life history is said to be mono‐, di‐, or trimorphic. Certain features of some algal life histories are considered in relation to the problem of deciding what is a recognizable somatic phase and it is concluded that: morphologically similar haploid and diploid thalli represent one somatic phase, the hypnozygospore of various Chlorophyta represents a somatic phase, the carposporophyte of the Florideae is a somatic phase. Adelophycean phases are considered, but interpretation in many cases is hampered by the imperfect state of our knowledge. Known monomorphic life histories include diplonts and diplohaplonts, and dimorphic life histories contain both diplohaplonts and haplonts. The only clearly established trimorphic life histories are haplonts. The designation of the individual somatic phases of mono‐, di‐ and trimorphic life histories is discussed. It is shown that the terms gametop...

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Section: ( D ) the Carposporophyte Of The Florideaesupporting

confidence: 88%

Life Histories in the Algae With Special Reference to the Chlorophyta, Phaeophyta and Rhodophyta

Drew

1955

Biological Reviews

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“…He considered light intensity as a major controlling factor for the development of hairs . Rosenvinge (1911) and Oltmanns (1922), working with certain red and brown algae respectively, had also shown light to be an important factor for production of hairs and found a reduction of the number of hairs in low light intensity . In contrast, the situation in green algae seems to be quite different .…”

Section: Discussionmentioning

confidence: 99%

Observations on the morphology, reproduction and cytology of stigeoclonium pascheri (vischer) cox et bold (chaetophorales-chlorophyceae) and their bearing on the validity of the genus caespitella vischer

Shyam

Sarma

1980

Hydrobiologia

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The present communication deals with the morphology, reproduction and cytology of Stigeoclonium pascheri (formerly described as Caespitella pascheri Vischer). Effects of various concentrations of nitrate and variations in intensity and duration of light period in 24 hr LD cycles were studied on cultures of this alga in relation to the type and extent of branching and occurrence or absence of hair formation .

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“…In material of C. areolata examined here the zoosporangia are solitary and terminal or subterminal and may be in the same part of an axis, although not in series. Stages in spermocarp and oospore development correspond to those described by Oltmanns (1922) and Fritsch (1935) for C. pulvinata, but the paired supporting filaments are unique to C. areolata. Mature spermocarps with oospores having pronounced areolate golden-brown thickening, are not described for other cushionforming Coleochaete species.…”

mentioning

confidence: 82%

Non-marine algae of Australia : 4. Floristic survey of some colonial green macroalgae (Chlorophyta)

Entwisle¹,

Skinner²

2002

Telopea

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Morphologie und Biologie der Algen

Cited by 246 publications

References 0 publications

Life Histories in the Algae With Special Reference to the Chlorophyta, Phaeophyta and Rhodophyta

Life Histories in the Algae With Special Reference to the Chlorophyta, Phaeophyta and Rhodophyta

Observations on the morphology, reproduction and cytology of stigeoclonium pascheri (vischer) cox et bold (chaetophorales-chlorophyceae) and their bearing on the validity of the genus caespitella vischer

Non-marine algae of Australia : 4. Floristic survey of some colonial green macroalgae (Chlorophyta)

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