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Hassallia

Generic name: HASSALLIA Berkeley ex Bornet et Flahault 1888. Ann. Sci. Nat. Bot., ser. 7, 5: 115.
Synonyms: [HASSALLIA Berkeley, in Hassall, History of the British fresh-water Algae, I, p. 231, 1845, pro parte ex Bornet et Flahault: Scytonema, Sirosiphon, Hapalosiphon, Tolypotrix spec.
Diagnosis:
Bornet et Flahault (1888): Fila fragilia pseudo-ramosa; pseudo-rami solitarii, eruptione laterali trichomatis formati, sub heterocysta ipsa, rarius inter heterocystas, egredientes. Vagina tenuis, sicca, fragilis. Algae crustaceo-tomentosae, minutae.
Type species: Hassallia byssoidea Hassall ex Bornet et Flahault 1888
Descriptions:
Komárek (1992): Filamentous; filaments heteropolar, with basal parts with heterocytes and free apical ends, commonly falsely branched with solitary lateral branches initiating at the heterocytes (mainly unipored) and fragile (sometimes liberating from the “mother” filament), united in fasciculate, caespitose, crustaceous, thin or woolly mats, sometimes creeping on a substrate; branches diverging from the main trichome, more or less short, usually arcuated. Sheaths thick, firm, lamellated, colourless or yellow-brown, open at the apex. Trichomes and branches with basal (rarely also with intercalar) heterocytes, cylindrical, not attenuated or slightly
attenuated at apexes, constricted at the cross walls. Cells barrel-shaped, shorter than wide up to discoid; end cells slightly narrowed and widely rounded, with granular content. Aerotopes and akinetes lacking.
Genotype differences, molecular data:
Reproduction strategies, life cycles, cell division:
Komárek (1992): Cells divide crosswise to the trichome axis, characteristic are the terminal meristematic zones. Reproduction by separated branches or hormogonia, which germinate at both sides, but later (after formation of heterocytes); they change in heteropolar growth.
Ultrastructure:
Taxonomic position, higher hierarchy: Cyanophyceae,
Nostocales, Microchaetaceae, Tolypotrichoideae
Notes to taxonomy, misinterpretations:
Ecology, ecophysiology, ecological significance:
Komárek (1992): Majority of species are aerophytic, growing on stones and bark of trees, several species occur rarely in submerse biotopes. Distribution of various species is not well known, mainly because of many misidentifications.
Bornet et Flahault (1888): Plantae terrestres.
Physiology and biochemistry:
Distribution, endemism, problematic citations:
Reference strain:
Infrageneric scheme, species concept:

List of species:
Hassallia bouteillei Bornet et Flahault 1888. Ann. Sci. Nat. Bot., ser. 7, 5: 116
Hassallia byssoidea Hassall ex Bornet et Flahault 1888. Ann. Sci. Nat. Bot., ser. 7, 5: 116
Hassallia californica Johansen et Flechtner in Flechtner, Johansen et Belnap 2008. Western North American Naturalist 68: 417

Hassallia discoidea Gardner 1927
Hassallia granulata Gardner 1927
Hassallia manginii Frémy 1927
Hassallia pseudoramosissima Johansen et Flechtner in Flechtner, Johansen et Belnap 2008. Western North American Naturalist 68: 417
Hassallia pulvinata Frémy 1930
Hassallia usambarensis Hieronymus in Engler et Prantl 1895

Unclear taxa:
Hassallia brevis Gardner 1927
Hassallia ceylonica Schmidle 1900
Hassallia fragilis Gardner 1927
Hassallia heterogenea Gardner 1927
Hassallia rechingeri Wille 1903
Hassallia scytonematoides Gardner 1927
Tolypothrix bouteillei "(Brébisson et Desmazières) Forti" sensu Desikachary 1959
Tolypothrix byssoidea var. polyclados Frémy 1928
Tolypothrix letestui Frémy 1930
Tolypothrix magna Bharadwaya 1934

Keys:

List of stains:

CCALA 823, CCALA 841

Drawings:
Komárek 1992
Application technology:
Literature:

  2.1 taxonomy: Bornet et Flahault 1888, Geitler 1942, Komárek 1992
  2.2 cytomorphology:
  2.3 16S rRNA sequencing:
  2.4 biology and life cycles:
  2.5 ecology: