Hedstroemia

{{Short description|Extinct genus of algae}}

{{for|the trilobite genus|Hedstroemia (trilobite)}}

{{Automatic taxobox

| fossil_range = {{fossil range|Llandovery|Upper Devonian|ref={{cite web|url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=68849|title=Fossilworks: Hedstroemia|author=|date=|website=paleodb.org|access-date=7 April 2018}}}}

| taxon = Hedstroemia

| authority = A. Rothpletz, 1913

| type_species = †Hedstroemia halimedoidea

| type_species_authority = A. Rothpletz, 1913

| subdivision_ranks = Species

| subdivision_ref = {{cite journal|first1=Lijing|last1=Liu|first2=Yasheng|last2=Wu|first3=Haijun|last3=Yang|first4=Robert|last4=Riding|year=2016|title=Ordovician calcified cyanobacteria and associated microfossils from the Tarim Basin, Northwest China: systematics and significance|url=http://www.robertriding.com/pdf/liu-etal-2016-tarim.pdf|journal=Journal of Systematic Palaeontology|volume=14|issue=3|pages=183–210|doi=10.1080/14772019.2015.1030128|s2cid=129684955}}

| subdivision = {{Species list

| †Hedstroemia bifilosa | A. Rothpletz, 1913

| †Hedstroemia halimedoidea | A. Rothpletz, 1913

}}

}}

The extinct genus Hedstroemia was once thought to be a rivulariacean cyanobacterium.{{update inline|?=yes|reason=It seems to be considered a cyanobacterium again judging by recent articles, including two that are used on this page as references.|date=March 2021}} It forms oval blobs composed of sinuous tubes that have rounded outlines and occurs in conjunction with Solenopora.{{Cite journal | last1 = Riding | first1 = R. | last2 = Watts | first2 = N. | title = Silurian algal reef crest in Gotland | journal = Naturwissenschaften | volume = 68 | issue = 2 | pages = 91 | year = 1981 | doi = 10.1007/BF01047229|bibcode = 1981NW.....68...91R | s2cid = 8834679 }}

Hedstroemia was formerly assigned to the now obsolete taxon porostromata.{{Cite book|last=Monty|first=C. L.|title=Phanerozoic Stromatolites |chapter=Spongiostromate vs. Porostromate Stromatolites and Oncolites |date=1981|editor-last=Monty|editor-first=Claude|chapter-url=https://link.springer.com/chapter/10.1007/978-3-642-67913-1_1|language=en|location=Berlin, Heidelberg|publisher=Springer|pages=1–4|doi=10.1007/978-3-642-67913-1_1|isbn=978-3-642-67913-1}} In 2020, the genus was assigned to the cyanobacteria order Nostocales.{{Cite journal|author1=Lijing Liu |author2=Yasheng Wu |author3=Hongping Bao |author4=Hongxia Jiang |author5=Lijing Zheng |author6=Yanlong Chen |year=2020 |title=Diversity and systematics of Middle-Late Ordovician calcified cyanobacteria and associated microfossils from Ordos Basin, North China |journal=Journal of Paleontology |volume=95 |pages=1–23 |doi=10.1017/jpa.2020.82 |s2cid=226349226 }}