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Hamburg, Germany

Hartmann H.E.K.,Biozentrum Klein Flottbek | Meve U.,University of Bayreuth | Liede-Schumann S.,University of Bayreuth
Plant Ecology and Evolution | Year: 2011

Background and aims - The genus Trianthema (Aizoaceae - Sesuvioideae) is poorly known. Identification of two well circumscribed subgenera is followed by a revision of T. subg. Papularia, presenting for the first time a list of all species identified as members of the subgenus. Methods - Normal practices of herbarium taxonomy have been applied to study all herbarium material available, mainly from AD, B, BRI, C, DNA, E, HBG, K, L, MO, UTB, WAG, and Z. Key results - Based on an extensive investigation into as many characters as possible, results permitted the identification of new character states, supporting the division of the genus Trianthema into the two subgenera, Trianthema and Papularia. In consequence, species limits can be reliably re-circumscribed, resulting in the recognition of 17 species in the latter subgenus, of which five are described as new here: T. corallicola, T. mozambiquensis, T. pakistanensis, T. ufoensis, and T. vleiensis. Raised to species rank are T. clavata and T. corymbosa, and emended and re-circumscribed are T. crystallina, T. hereroensis, T. parvifolia, T. salsoloides, T. sanguinea, T. sedifolia, T. sheilae, T. transvaalensis, and T. triquetra. Unaltered is the description of T. argentina, for which, however, the critical features are also described and figured in order to permit a sound identification of each species in T. subg. Papularia. Distribution patterns are discussed and possible evolutionary pathways are suggested on a morphological base. © 2011 National Botanic Garden of Belgium and Royal Botanical Society of Belgium-ISSN 2032-3921.

Hartmann H.E.K.,Biozentrum Klein Flottbek
Bradleya | Year: 2013

Initiated by the description of a new species in Delosperma closely resembling members of the genus Ectotropis, an investigation was begun again to determine the circumscription of Ectotropis. As a result, Ectotropis as a genus can be confirmed, based mainly on flower and fruit morphology, and two species are recognized: E. alpina N.E. Br, and E. seanii-hoganii (Niederle) H.K. Hartmann & C. Schroder, comb. nov.

Hartmann H.E.K.,Biozentrum Klein Flottbek | Liede-Schumann S.,University of Bayreuth
Bradleya | Year: 2013

In a comprehensive study of the genus Drosanthemum, material was detected that differs fundamentally in molecular and morphological character states from the genus proper. Since it can neither be placed in any of the existing genera of the tribe Ruschieae, a new genus is described here, Knersia H.E.K. Hartmann & Liede gen nov., with K. diversifolia (L. Bolus) H.E.K. Hartmann & Liede comb. nov. as the single species.

Hartmann H.E.K.,Biozentrum Klein Flottbek | Liede-Schumann S.,University of Bayreuth
Bradleya | Year: 2014

Based on extensive morphological studies in more than 1,000 populations, two new subgenera are established in the genus Drosanthemum: D. subg. Decidua H.E.K.Hartmann and subg. Quadrata H.E.K.Hartmann; in the latter, a new species is described: D. tetramerum H.E.K. Hartmann. A key and descriptions of the included species are provided. © 2014 BCSS.

Numerous detailed studies have been made of climatically and environmentally influenced macroalgal geographic distribution patterns. However, so far, there have been only a few intrinsic investigations of the geographic distributions of microalgae. In order to investigate the physiological differences among geographically different microalgal strains, six Cosmarium strains were collected from various climate areas and studied. They were grown under a constant light-temperature regime (16°C and 30 μmol photons m-2 s-1) and nutrient supply. The arctic representative, C. crenatum var. boldtianum, and the typical tropical desmid, C. beatum, behaved like algae adapted to high light intensities, as judged from the distinctly high values of photosynthetic capacity and saturating irradiance measured, in accordance with the high solar radiation prevailing in their sampling areas. The arctic taxon appeared more optimally suited to the low cultivation temperature, as evidenced by the relatively high values of growth rates, maximum quantum yield and photosynthetic efficiency measured. The cosmopolitan taxa, C. meneghinii and C. punctulatum var. subpunctulatum, exhibited a high maximum quantum yield and photosynthetic efficiency concomitantly during growth, which explained their ubiquitous distribution. Nevertheless, two clones belonging to C. punctulatum var. subpunctulatum, collected from polar and mountainous tropical regions, differed significantly with regard to cell volume, growth rates, surface area to volume ratio and photosynthetic parameters. The physiological differences between the Cosmarium strains were in accordance with their geographic origin; they are discussed in detail in this study. Moreover, these differences were maintained despite the long-term cultivation under identical and constant laboratory conditions. © 2011 Springer Science+Business Media B.V.

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