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A Mediterranean population of Spongites fruticulosus (Rhodophyta, Corallinales), the type species of Spongites, and the taxonomic status of S. stalactitica and S. racemosa
No full textTetrasporangial male and female/carposporangial plants of a Mediterranean population of Spongites fruticulosus are described and compared with the type material of S. fruticulosus, Spongites racemosa and Spongites stalactitica. The three species were established by Kutzing on the basis of Mediterranean collections. The type material of S. fruticulosus is a rhodolith composed of a tetrasporangial plant possessing uniporate conceptacles, multistratose noncoaxial hypothallium and ovoid epithallial cells, growing on another unidentified sterile coralline with different vegetative characters. Spongites fruticulosus is lectotypified here with the tetrasporangial plant. The original material of S. racemosa represents a male plant of Neogoniolithon, here identified as Neogoniolithon racemosum (Kutzing) comb. nov. The type material of S. stalactitica is a rhodolith composed of a mixture of two species belonging to different genera: one, here selected as lectotype of S. stalactitica, is a female plant regarded as conspecific with S. fruticulosus. The second is the tetrasporophyte of a Neogoniolithon species. Detailed morphological-anatomical accounts of the species are presented, and their features are documented and discussed. The comparison between the Mediterranean types and new collections and the Australian population of S. fruticulosus revealed that Mediterranean plants have smaller sexual and asexual conceptacles and lack trichocytes. However, overlap in conceptacle dimensions and the rarity of trichocytes in the Australian specimens do not allow us to separate the Mediterranean and the Indo-Pacific populations into different species at this time
Valutazione del tasso di crescita in coltura delle alghe calcaree Lithophyllum stictaeforme e Mesophyllum lichenoides: primi risultati
No full textThe growth of the calcareous algae Lithophyllum stictaeforme (J.E. Areschoug) Hauck and Mesophyllum lichenoides (J. Ellis) M. Lemoine (Rhodophyta, Corallinales), two common Mediterranean coralligenous builders, ha sbeen estimated under controlled conditions in laboratory cultures, by marking the thalli with Alizarin-S. Preliminary results of marginal growth of M. lichenoides ranges from 1290 to 3260 μm/yr, with thickness increment from 10 to about 97 μm/yr. The thallus thickening in L. stictaeforme is 21-80 μm/yr
A re-description of Lithothamnion crispatum and the status of Lithothamnion superpositum (Rhodophyta, Corallinales)
No full textAfter re-examination of the original Hauck's collection, a buried, empty multiporate tetrasporangial conceptacle was detected in the lectotype material of Lithothamnion crispatum. The morphology and anatomy of the type material were compared to freshly collected representative plants from the Mediterranean. In L. crispatum, the five to seven rosette cells surrounding each pore of the tetra/bisporangial conceptacle roof are larger than the normal epithallial cells and undergo degeneration. As a consequence of the disintegration of the outermost cells in filaments surrounding the pore canals, the tetra/bisporangial conceptacle roofs appear pitted with depressions, each one hosting a pore and the surrounding rosette cells. A previous revision of the type material of Lithothamnion superpositum from South Africa showed this same tetra/bisporangial conceptacle roof structure and development, and corresponding vegetative and reproductive characters. These taxa are thus conspecific; therefore, L. superpositum is a younger heterotypic synonym of L. crispatum, the latter having nomenclatural priority. While the type specimen lacked gametangial plants, these are described for representative freshly collected material and found to be dioecious
Demografia e dinamica di popolazioni di Drosera presenti nella Riserva Regionale di Pian di Gembro (SO), SIC IT2040025
No full textRiordino e catalogazione delle raccolte floristiche di Ferdinando Sordelli depositate presso l’Herbarium Universitatis Mediolanensis (MI)
No full textA comparative study between Lithotamnion minervae and the type material of Millepora fasciculata (Corallinales, Rhodophyta)
No full textLithothamnion minervae is a crustose coralline alga recognized as a common rhodolith-forming species in the western Mediterranean basin. The species was erected in order to give a correct name and an unequivocal definition to the coralline misidentified for a long time as Lithothamnion fruticulosum. Details of the plant, such as the epithallial cells and the tetrasporangial or bisporangial and uniporate conceptacles are described on recently collected samples. It is shown that the two plants in the original collection of Millepora fasciculata belong to different taxa, and therefore a previous lectotypification (Woelkerling in Woelkerling & Lamy 1998) is superseded. The smaller of the two plants, which belongs to an undescribed species of Clathromorphum, is selected here as the new lectotype of M. fasciculata. The larger plant in the collection belongs to a species of Lithothamnion; it differs from L. minervae in having a smaller range of chamber diameters of multiporate conceptacles, embedded multiporate conceptacles filled with palisade cells and smaller perithallial cells
Trichocytes in Lithophyllum kotschyanum and Lithophyllum spp. (Corallinales, Rhodophyta) from the NW Indian Ocean
No full textThe current diagnosis of the genus Lithophyllum includes absent or rare trichocyte occurrence. After examining holotype material, single trichocytes have been revealed to occur abundantly in Lithophyllum kotschyanum Unger, and in freshly collected specimens of Lithophyllum spp. from the Red Sea, Gulf of Aden and Socotra Island (Yemen). Trichocyte occurrence is not considered a diagnostic character at specific or supraspecific levels in the Lithophylloideae, and the ecological significance of trichocyte formation is discussed. The generitype species, L. incrustans Philippi, does not show trichocytes nor do many other Lithophyllum species from diverse geographic localities, but the presence of abundant trichocytes in other congeneric taxa requires emendation of the genus diagnosis. Therefore, the diagnosis of Lithophyllum is here emended by eliminating the adjective "rare" in the sentence concerning trichocyte occurrence, as follows: "Trichocytes present or absent, if present occurring singly
Life history in Drosera L. (Droseraceae) emphasizing the natural hybrid Drosera x obovata Mert. And Koch
No full textThe genus Drosera L. in northern Italy: pollen morphology as a taxonomic tool
No full textThe pollen morphology of Drosera L. belonging to the Italian flora was studied by investigating alpine populations of D. intermedia, D. rotundifolia, D. anglica, and a natural hybrid, D. x obovata. Studies were carried out on fresh material by light microscopy and scanning electron microscopy. Features of the distal face seem to represent an important diagnostic element.
A pollen key, based on micro-morphological data, is presente
Life History in Drosera L. (Droseraceae) emphasizing the natural hybrid Drosera x obovata Mert. and Koch
No full textA study about the sporogenesis and gametogenesis of the hybrid Drosera x obovata and its parental species (D. rotundifolia and D. anglica) was carried on. D. x obovata, even if sterile, produces pollen tetrads and a male gametophyte structurally the same as the parental species’ one. However the pollen grains appear poor of protoplasmic papillae, which indicates low vitality. The investigations on the ovules allowed to follow the megasporogenesis and the megagametogenesis till the development of the embryos in the parental plants whereas in D. x obovata it has never been possible to observe an embryo
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