Solidago

{{Short description|Genus of plants in the family Asteraceae}} {{Automatic taxobox |image = Solidago virgaurea var. leiocarpa 02-2.jpg |image_caption = ''Solidago virgaurea'' var. ''leiocarpa'' |display_parents = 3 |taxon = Solidago |authority = L. 1753 not Mill. 1754 |synonyms_ref = <ref name=fna/> |synonyms = *''Actipsis'' Rafinesque *''Aster'' Linnaeus subg. ''Solidago'' (Linnaeus) Kuntze *''Leioligo'' Rafinesque }}

'''''Solidago''''', commonly called '''goldenrod''', is a genus of about 100<ref name=fna>{{cite web|url=http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=130659|title=''Solidago''|work=Flora of North America}}</ref> to 120<ref name=china>[http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=130659 ''Solidago''.] Flora of China.</ref> species of flowering plants in the family Asteraceae. Most are herbaceous perennial species found in open areas such as meadows, prairies, and savannas. They are mostly native to North America, including Mexico; a few species are native to South America and Eurasia.<ref name=fna/> Some American species have also been introduced into Europe and other parts of the world.

==Description== [[File:Bombus cryptarum - Solidago virgaurea - Keila2.jpg|thumb|left|European goldenrod is pollinated by ''Bombus cryptarum'']] ''Solidago'' species are perennials growing from woody caudices or rhizomes. Their stems range from decumbent (crawling) to ascending or erect, with a range of heights going from {{convert|5|cm|abbr=on}} to over a meter. Most species are unbranched, but some do display branching in the upper part of the plant. Both leaves and stems vary from glabrous (hairless) to various forms of pubescence (strigose, strigillose, hispid, stipitate-glandular or villous). In some species, the basal leaves are shed before flowering. The leaf margins are most commonly entire, but often display heavier serration. Some leaves may display trinerved venation rather than the pinnate venation usual across Asteraceae.<ref name=fna/>

The flower heads are usually of the radiate type (typical daisy flower heads with distinct ray and disc florets) but sometimes discoid (with only disc florets of mixed, sterile, male and types). Only ray florets are female, others are male, hermaphroditic or entire sterile. Head involucres are campanulate to cylindric or attenuate. Floret corollas are usually yellow, but white in the ray florets of a few species (such as ''Solidago bicolor''); they are typically hairless. Heads usually include between 2 and 35 disc florets, but in some species this may go up to 60. Filaments are inserted closer to the base of the corolla than its middle. Numerous heads are usually grouped in complex compound inflorescences where heads are arranged in multiple racemes, panicles, corymbs, or secund arrays (with florets all on the same side).<ref name=fna/>

''Solidago'' cypselae are narrowly obconic to cylindrical in shape, and they are sometimes somewhat compressed. They have eight to 10 ribs usually and are hairless or moderately hispid. The pappus is very big with barbellate bristles.<ref name=fna/> [[Image:Goldenrodbee.jpg|thumb|right|Goldenrod and visiting ''Cerceris'' wasp]] The many goldenrod species can be difficult to distinguish, due to their similar bright, golden-yellow flower heads that bloom in late summer. Propagation is by wind-disseminated seeds or by spreading underground rhizomes which can form colonies of vegetative clones of a single plant. They are mostly short-day plants and bloom in late summer and early fall. Some species produce abundant nectar when moisture is plentiful, or when the weather is warm and sunny.

The section ''Ptarmicoidei'' is sometimes treated as a separate genus ''Oligoneuron'',<ref name=fna_ptarmicoidei>{{cite web|url=http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=316945|title=''Solidago'' Linnaeus sect. ''Ptarmicoidei'' (House) Semple & Gandhi|work=Flora of North America}}</ref> and is dropped by flat-topped to rounded corymbiform flowerheads.

==Taxonomy== ''Solidago'' is in the family Asteraceae (formerly known as Compositae), a diverse and widespread clade containing approximately 23,000 species and 12 tribes, which inhabit all continents except Antarctica. Within Asteraceae, ''Solidago'' is in the tribe Astereae and the subtribe Solidagininaeae.<ref name="springer.com">{{Cite book|url=https://www.springer.com/series/1306|title=The Families and Genera of Vascular Plants|language=en}}</ref>

The genus ''Solidago'' is monophyletic as indicated by morphological characters<ref name="Hood-2003">{{Cite journal|last1=Hood|first1=Jennifer L.A.|last2=Semple|first2=John C.|title=Pappus Variation in ''Solidago'' (Asteraceae: Astereae)|date=2003|jstor=41961022|journal=SIDA, Contributions to Botany|volume=20|issue=4|pages=1617–1630}}</ref> and molecular evidence.<ref name="Zhang-1996">{{Cite thesis |last=Zhang |first=Jie J. |year=1996 |title=A Molecular Biosystematic Study on North American ''Solidago'' and Related Genera (Asteraceae: Astereae) Based on Chloroplast DNA RFLP Analysis [microform]. |url=https://www.researchgate.net/publication/35258075 |publisher=University of Waterloo}}</ref><ref name="Semple-2016">{{Cite journal|last=Semple|first=John|date=2016-05-11|title=An Intuitive Phylogeny and Summary of Chromosome Number Variation in the Goldenrod genus ''Solidago'' (Asteraceae: Astereae)|url=https://www.researchgate.net/publication/303366007|journal=Phytoneuron|volume=2016-32|pages=1–9}}</ref> All ''Solidago'' species are herbaceous perennials, growing from approximately 2 cm to 2.5 m tall. Yellow to white, pistillate ray flowers and yellow, perfect disc florets are characteristic of ''Solidago'' inflorescences, which have a wide range of shapes.<ref name="springer.com"/> Molecular studies<ref name="Schilling-2008" /><ref name="Zhang-1996" /> using nuclear rDNA have hypothesized boundaries on the genus ''Solidago'', but there have been difficulties in parsing out evolutionary relationships at the sub-genus scale and defining which should be included and separated from ''Solidago''.

===''Solidago'' and related taxa=== Related Asteraceae genera, such as ''Chrysoma'', ''Euthamia'', and ''Oreochrysum'', have been included within ''Solidago'' at one point or another,<ref name="Anderson-1975">{{Cite journal|last1=Anderson|first1=Loran C.|last2=Creech|first2=Jessica B.|date=1975|title=Comparative Leaf Anatomy of ''Solidago'' and Related Asteraceae|jstor=2441956|journal=American Journal of Botany|volume=62|issue=5|pages=486–493|doi=10.2307/2441956}}</ref> but morphological evidence<ref name="Phytologia-1994">{{Cite journal|date=1994|title=Subtribal Classification of the Astereae (Asteraceae)|last1=Nesom|first1=Guy L.|url=http://biostor.org/reference/131828|journal=Phytologia|language=en|volume=76|issn=0031-9430}}</ref><ref name="Anderson-1975" /><ref name="Rhodora-1981">{{Cite journal|date=1981|title=The Taxonomy of the Genus ''Euthamia'' |url=http://biostor.org/reference/138608|journal=Rhodora|language=en|volume=83|issue=836|issn=0035-4902}}</ref> has suggested otherwise. In a study comparing morphological characters of ''Solidago'' and related subgroups, the authors consider the subjectivity of classifying a genus and how to define it within broader tendencies concerning the taxonomy of North American Asteraceae. Little to no differences were observed between ''Solidago'' and the subgroups in terms of karyotype. However, external morphological characters such as habit, or the general appearance of the plant and how a suite of traits contribute to its phenotype; pappus size; and the point of freeing of stamen filaments from the corolla tube, are useful classification schemes for ''Solidago'', since they are applied to differentiating between Asteraceae taxa. One school of Asteraceae taxonomy thought unites all taxa sharing similar floral head structure and subsequently ignores deviation from this morphology, while another places greater weight on these morphological deviations. The authors argue that the latter opinion should be applied. Since there is no theoretical foundation for relative taxonomic importance of traits, they assert that habit should be a central trait when defining taxa, and subsequently that all the subgroups considered in their study (''Brachychaeta'', ''Chrysoma'', ''Euthamia'', ''Oligoneuron'', and ''Petradoria'') should be segregated from ''Solidago''.<ref name="Kapoor-1966">{{Cite journal|last1=Kapoor|first1=B. M.|last2=Beaudry|first2=J. R.|date=1966-09-01|title=Studies on ''Solidago''. Vii. the Taxonomic Status of the Taxa ''Brachychaeta'', ''Brintonia'', ''Chrysoma'', ''Euthamia'', ''Oligoneuron'' and ''Petradoria'' in Relation to ''Solidago''|journal=Canadian Journal of Genetics and Cytology|volume=8|issue=3|pages=422–443|doi=10.1139/g66-053|issn=0008-4093}}</ref>

Results from a leaf anatomy study comparing differences in mesophyll, bundle sheath extensions, and midvein structure, among others in a suite of leaf traits,<ref name="Anderson-1975" /> are incongruent with those in an earlier study.<ref name="Kapoor-1966" /> Based on the lack of bundle sheath extensions, it is suggested that ''Chrysoma'', ''Euthamia'', ''Gundlachia'', and ''Petradoria'' should be distinct taxa and outside of ''Solidago''.<ref name="Anderson-1975" /> However, ''Brachychaeta'', ''Brintonia'', ''Oligoneuron'', ''Oreochrysum'', and ''Aster ptarmicoides'' should be considered as components of ''Solidago''. To summarize, the relation of ''Brachychaeta'' and ''Oligoneuron'' to ''Solidago'' is inconsistent based on these results.<ref name="Kapoor-1966" /><ref name="Anderson-1975" /> Both support the separation of ''Chrysoma'', ''Euthamia'', and ''Petradoria'' from ''Solidago''. A study reviews the taxonomic position of ''Oligoneuron'' relative to ''Solidago'', as based on taxonomic evidence, treats it as separate from ''Solidago'',<ref name="Phytologia-1994" /> similarly to Kapoor & Beaudry (1966). The first molecular phylogeny based on chloroplast DNA treats ''Brachychaeta'', ''Brintonia'', ''Oligoneuron'', and ''Oreochrysum'' as constituents of ''Solidago''.<ref name="Zhang-1996" /> Using consensus trees from ITS data, another study found support for ''Oligoneuron'' as part of ''Solidago'',<ref name="Beck-2004">{{Cite journal|last1=Beck|first1=James B.|last2=Nesom|first2=Guy L.|last3=Calie|first3=Patrick J.|last4=Baird|first4=Gary I.|last5=Small|first5=Randall L.|last6=Schilling|first6=Edward E.|date=2004|title=Is Subtribe Solidagininae (Asteraceae) Monophyletic?|jstor=4135444|journal=Taxon|volume=53|issue=3|pages=691–698|doi=10.2307/4135444 |bibcode=2004Taxon..53..691B }}</ref> and the findings of Zhang (1996). More recently, an analysis of combined ITS and ETS data provided additional support for the inclusion of ''Oligoneuron'' as part of ''Solidago''.<ref name="Schilling-2008" />

Until the 1980s, the genus ''Euthamia'' was largely considered to be a part of ''Solidago'' due to morphological similarities between species in both genera, and a history of synonymy of ''Solidago lanceolata'' and ''Euthamia graminifolia''.<ref name="Rhodora-1981" /> As mentioned, the lack of bundle sheath extensions in ''Euthamia'' compared to ''Solidago'',<ref name="Anderson-1975" /> and deviations in floral morphology<ref name="Kapoor-1966" /> present evidence for separation of these taxa. A taxonomy of ''Euthamia'' as a genus was presented, providing a detailed description of distinguishing external morphological characters, such as fibrous-roots, sessile leaves, and mostly corymbiform inflorescences.<ref name="Rhodora-1981" />

===Evolutionary relationships within ''Solidago''=== Chromosome counts and advances in molecular systematics have enabled greater understanding of evolutionary relationships within ''Solidago''. At the time a taxonomy of ''Solidago'' was published,<ref name="Phytologia-1994" /> related taxa causing contention, such as ''Chrysoma'', ''Euthamia'', ''Oligoneuron'', and ''Petradoria'', were excluded from this genus. The number of ''Solidago'' species has remained relatively stable, around 120, with approximately 80 in North America.<ref name="Semple-2016" /><ref name="Phytologia-1994" /> Due to monophyletic support for the New World taxa<ref name="Beck-2004" /><ref name="Hood-2003" /> and taxonomic difficulties with Old World taxa, the taxonomy provided in the 1990s<ref name="Phytologia-1994" /> only includes North American taxa and thus treats ''Solidago'' as non-monophyletic. Existing molecular-based phylogenies provide monophyletic support for ''Solidago''<ref name="Schilling-2008" /><ref name="Beck-2004" /><ref name="Semple-2016" /><ref name="Zhang-1996" /> given its inclusion of ''Oligoneuron''.

Chromosome counts have proven to be a valuable character in ''Solidago'' taxonomy and in elucidating the cytogeographic history of the genus. Similar chromosome counts may indicate close evolutionary relationships, while different chromosome numbers may suggest distant relationships through reproductive isolation. Chromosome counts have been studied extensively in North America;<ref>{{Cite journal|last1=Cook|first1=Rachel E.|last2=Semple|first2=John C.|date=2008-11-13|title=Cytogeography of ''Solidago'' subsect. ''Glomeruliflorae'' (Asteraceae: Astereae)|journal=Botany|volume=86|issue=12|pages=1488–1496|doi=10.1139/B08-087|bibcode=2008Botan..86.1488C |issn=1916-2790}}</ref><ref>{{Cite journal|last1=Semple|first1=John|last2=Watanabe|first2=Kuniaki|date=2013-03-02|title=A Review of Chromosome Numbers in Asteraceae with Hypotheses on Chromosomal Base Number Evolution|url=https://www.researchgate.net/publication/48460015}}</ref> all ''Solidago'' species have a base chromosome number of x=9, but the following ploidy levels have been observed: 2x, 3x, 4x, 6x, 8x, 10x, 12x, and 14x.

Though negligible differences in karyotype among ''Solidago'' and related genera were found,<ref name="Kapoor-1966" /> ''Solidago'' taxa with multiple cytotypes are more common than those with one.<ref name="Semple-2016" /> Although chromosome count is a useful metric for differentiating among ''Solidago'' taxa, it may be problematic due to the frequent variation in ploidy levels. Cytogeographic patterns in the ''Solidago gigantea'' complex, with tetraploids occurring in eastern North America and hexaploids in Oregon and Washington, were observed.<ref>{{Cite journal|last1=Semple|first1=John C.|last2=Ringius|first2=Gordon S.|last3=Leeder|first3=Colleen|last4=Morton|first4=Gary|date=1984-07-01|title=Chromosome Numbers of Goldenrods, ''Euthamia'' and ''Solidago'' (Compositae: Astereae). II. Additional Counts with Comments on Cytogeography|journal=Brittonia|language=en|volume=36|issue=3|pages=280–292|doi=10.2307/2806528|issn=0007-196X|jstor=2806528|bibcode=1984Britt..36..280S |s2cid=186241866}}</ref> Cytogeographic patterns are also observed in the ''Solidago canadensis'' complex: hexaploids within ''S. canadensis'' have been observed east of the Great Plains and are treated as ''Solidago altissima'', and diploids and tetraploids occurring in the Great Plains are treated as ''Solidago gilvocanescens''. The taxonomic status of ''Solidago ptarmicoides'' created an extensive debate due to frequency hybridization of ''S. ptarmicoides'' with members of the ''Ptarmicoidei'' section of ''Solidago''.<ref name=fna/> It was asserted that ''S. ptarmicoides'' should be united with ''Solidago'' rather than the genus ''Aster'' due to external morphological features such as similar pappus length as well as the same chromosome base (x=9). Information about chromosome number is still a crucial part of current understanding and phylogenies of ''Solidago''.<ref name="Semple-2016" />

== Ecology == Goldenrod is considered a keystone species, and has been called the single most important plant for North American pollinator biodiversity.<ref>{{cite web |last1=Perkins |first1=Deborah |title=Goldenrods: Top Plant for Boosting Biodiversity |url=https://www.nrcm.org/blog/first-light-wildlife-habitats/goldenrods-top-plant-boosting-biodiversity/ |website=ncrm.org |date=23 September 2019 |publisher=Natural Resources Council of Maine}}</ref><ref>{{cite web |title=Goldenrod (Solidago) Is Trending! |url=https://www.nurturenativenature.com/post/goldenrod-solidago-is-trending |website=nurturenativenature.com|date=29 December 2020 }}</ref> Goldenrod species are used as a food source by the larvae of many Lepidoptera species. As many as 104 species of butterflies and moths use it as a host plant for their larvae, and 42 species of bees are goldenrod specialists, visiting only goldenrod for food.<ref>{{cite web |title=Keystone Native Plants Eastern Temperate Forests - Ecoregion 8 |url=https://www.nwf.org/-/media/Documents/PDFs/Garden-for-Wildlife/Keystone-Plants/NWF-GFW-keystone-plant-list-ecoregion-8-eastern-temperate-forests.ashx?la=en&hash=1E180E2E5F2B06EB9ADF28882353B3BC7B3B247D |website=nwf.org |publisher=National Wildlife Federation}}</ref> Some lepidopteran larvae bore into plant tissues and form a bulbous tissue mass called a gall around it, upon which the larva then feeds. Various parasitoid wasps find these galls and lay eggs in the larvae, penetrating the bulb with their ovipositors. Woodpeckers are known to peck open the galls and eat the insects in the center.<ref>{{cite journal|title=Foraging patterns of Eastern gray squirrels (''Sciurus carolinensis'') on goldenrod gall insects, a potentially important winter food resource|author=Shealers, D. A.|pages=102–109|journal=The American Midland Naturalist|volume=142|issue=1|date=July 1999|doi=10.1674/0003-0031(1999)142[0102:FPOEGS]2.0.CO;2|s2cid=85741057 |issn=0003-0031|display-authors=etal}}</ref>

Goldenrods have become invasive species in many parts of the world outside their native range, including China, Japan, Europe and Africa.<ref>{{cite journal |last1=Popay |first1=I. |last2=Parker |first2=C. |url=https://www.cabi.org/isc/datasheet/50599 |title=Solidago canadensis (Canadian goldenrod) |journal=Invasive Species Compendium |date=2014 |volume=CABI Compendium |publisher=CAB International |doi=10.1079/cabicompendium.50599 }}</ref><ref>{{cite journal | last1=Meyer | first1=G. | url=https://www.cabi.org/isc/datasheet/50575 | title=Solidago gigantea (Giant goldenrod) | journal=CABI Compendium | date=2014 | volume=CABI Compendium | doi=10.1079/cabicompendium.50575 | doi-access=free }}</ref> ''Solidago canadensis'', which was introduced as a garden plant in Central Europe, has become common in the wild, and in Germany is considered an invasive species that displaces native vegetation from its natural habitat.

==Use and cultivation== Young goldenrod leaves are edible.<ref>[http://nhguide.dbs.umt.edu/index.php?c=plants&m=desc&id=263 ''Solidago missouriensis'', Missouri goldenrod.] {{webarchive|url=https://web.archive.org/web/20130927231934/http://nhguide.dbs.umt.edu/index.php?c=plants&m=desc&id=263 |date=2013-09-27 }} Northern Rockies Natural History Guide. University of Montana, Missoula.</ref> Traditionally, Native Americans use the seeds of some species for food.<ref>[http://herb.umd.umich.edu/herb/search.pl?searchstring=Solidago+nemoralis ''Solidago nemoralis''.] Native American Ethnobotany. University of Michigan, Dearborn.</ref> Herbal teas are sometimes made with goldenrod.<ref>[http://umm.edu/health/medical/altmed/herb/goldenrod Goldenrod.] Complementary and Alternative Medicine Guide. University of Maryland Medical Center.</ref>

Goldenrod often is inaccurately said to cause hay fever in humans.<ref name="Corporation2001"/> The pollen causing this allergic reaction is produced mainly by ragweed (''Ambrosia'' sp.), blooming at the same time as the goldenrod and pollinated by wind. Goldenrod pollen is too heavy and sticky to be blown far from the flowers, and is pollinated mainly by insects.<ref name="Corporation2001">{{cite book|author=Marshall Cavendish Corporation|title=Endangered Wildlife and Plants of the World: Fra-Igu|url=https://books.google.com/books?id=40jA0MOWejIC&pg=PA632|year=2001|publisher=Marshall Cavendish|isbn=978-0-7614-7199-8|pages=632–}}</ref> Frequent handling of goldenrod and other flowers, however, can cause allergic reactions, sometimes irritating enough to force florists to change occupation.<ref>{{cite journal|pmid=9534922|date=Feb 1998|author=de Jong, N. W.|title=Occupational allergy caused by flowers|volume=53|issue=2|pages=204–9|issn=0105-4538|journal=Allergy|doi=10.1111/j.1398-9995.1998.tb03872.x|s2cid=41094680|display-authors=etal}}</ref> Goldenrods are attractive sources of nectar for bees, flies, wasps, and butterflies. Honey from goldenrods often is dark and strong because of admixtures of other nectars. However, when honey flow is strong, a light (often water-clear), spicy-tasting monofloral honey is produced. While the bees are ripening the honey produced from goldenrods, it has a rank odour and taste; the finished honey is much milder.

Goldenrods are, in some places, considered a sign of good luck or good fortune.<ref name="Silverthorne2002"/> They are considered weeds by many in North America, but they are seen as invasive plants in Europe, where British gardeners adopted goldenrod as a garden subject.{{citation needed|date=November 2022}} Goldenrod began to gain some acceptance in U.S. gardening (other than wildflower gardening) during the 1980s.{{citation needed|date=November 2022}}

Goldenrods are used to make yellow dyes and lake pigments.

===Cultivated species=== Cultivated goldenrods include ''S. bicolor'', ''S. caesia'', ''S. canadensis'', ''S. cutleri'', ''S. riddellii,'' ''S. rigida'', ''S. shortii'', and ''S. virgaurea''.<ref name="JelittoSchacht1995">{{cite book|author1=Jelitto, L.|author2=Schacht, W.|title=Hardy Herbaceous Perennials: A–K ; Vol. 2, L–Z|url=https://books.google.com/books?id=efFzRAAACAAJ|access-date=4 October 2010|year=1995|publisher=Timber Press|isbn=978-0-88192-159-5|page=629}}</ref>

A number of cultivars have been selected, including several of hybrid origin. A putative hybrid with aster, known as ×''Solidaster'' is less unruly, with pale yellow flowers, equally suitable for dried arrangements. Molecular and other evidence points to ×''Solidaster'' (at least the cultivar 'Lemore') being a hybrid of ''Solidago ptarmicoides'' and ''Solidago canadensis'', the former now in ''Solidago'', but likely the "aster" in question.<ref name="Schilling-2008">{{cite journal|url=http://web.utk.edu/~rsmall/Solidaster.pdf|last1=Schilling|first1=E. E.|year=2008|title=Molecular Analysis of ''Solidaster'' cv. Lemore, a Hybrid Goldenrod (Asteraceae)|journal=Journal of the Botanical Research Institute of Texas|volume=2|pages=7–18|display-authors=etal}}</ref>

The cultivars 'Goldenmosa'<ref>{{cite web|title=RHS Plant Selector - ''Solidago'' 'Goldenmosa'|url=http://apps.rhs.org.uk/plantselector/plant?plantid=1848|access-date=10 June 2013}}</ref> and ''S.'' × ''luteus'' 'Lemore'<ref>{{cite web|title=RHS Plant Selector - ''Solidago'' × ''luteus'' 'Lemore'|url=http://apps.rhs.org.uk/plantselector/plant?plantid=2054|access-date=10 June 2013}}</ref> have gained the Royal Horticultural Society's Award of Garden Merit.<ref>{{cite web | url = https://www.rhs.org.uk/plants/pdfs/agm-lists/agm-ornamentals.pdf | title = AGM Plants - Ornamental | date = July 2017 | page = 98 | publisher = Royal Horticultural Society | access-date = 12 November 2018}}</ref>

===Industrial use=== Inventor Thomas Edison experimented with goldenrod to produce rubber, which it contains naturally.<ref>{{cite magazine|url=https://content.time.com/time/subscriber/article/0,33009,881890,00.html|author=|title=Goldenrod Rubber|date=December 16, 1929|magazine=Time|access-date=June 6, 2017}}</ref> Edison created a fertilization and cultivation process to maximize the rubber content in each plant.<ref>{{Cite web |title=SL345/SS548: Fertilizer Experimentation, Data Analyses, and Interpretation for Developing Fertilization Recommendations—Examples with Vegetable Crop Research |url=https://edis.ifas.ufl.edu/publication/SS548 |access-date=2022-06-13 |website=edis.ifas.ufl.edu |language=en}}</ref> His experiments produced a {{convert|12|ft|m|adj=mid|-tall|abbr=on}} plant that yielded as much as 12% rubber, and the new variant was named ''Solidago edisoni'',<ref>{{cite news |title=Phonograph exhibit hints at rubber invention |url=https://www.orlandosentinel.com/1992/10/04/phonograph-exhibit-hints-at-rubber-invention/ |access-date=19 December 2024 |publisher=The Orlando Sentinel |date=4 October 1992}}</ref><ref>{{cite book |last1=Thulesius |first1=Olav |title=Edison in Florida: the Green Laboratory |date=1997 |publisher=University Press of Florida |location=Gainesville |isbn=0-8130-1521-9 |pages=83–93}}</ref> also called ''Solidago edisoniana''.<ref>{{cite news |last1=Vargues |first1=Lisa |title=In Search of Thomas Edison's Botanical Treasures |url=https://www.nybg.org/blogs/science-talk/2013/10/in-search-of-thomas-edisons-botanical-treasures/ |access-date=19 December 2024 |publisher=The New York Botanical Garden |date=30 October 2013}}</ref> The tires on the Model T given to him by his friend Henry Ford were made from goldenrod. Like George Washington Carver, Henry Ford was deeply interested in the regenerative properties of soil and the potential of alternative crops such as peanuts and soybeans to produce plastics, paint, fuel and other products.<ref>{{Cite web |last=Harris |first=Karen |title=George Washington Carver And Henry Ford Worked On Experimental Projects Together |url=https://historydaily.org/george-washington-carver-henry-ford-experiments |access-date=2022-06-13 |website=History Daily |language=en}}</ref>

Ford had long believed that the world would eventually need a substitute for gasoline, and supported the production of ethanol (or grain alcohol) as an alternative fuel.<ref>{{Cite web |date=2012-11-25 |title=Henry Ford, Charles Kettering and the fuel of the future |url=https://environmentalhistory.org/people/henry-ford-charles-kettering-and-the-fuel-of-the-future/ |access-date=2022-06-13 |website=Environmental history |language=en-US}}</ref> In 1942, he would showcase a car with a lightweight plastic body made from soybeans. Ford and Carver began corresponding via letter in 1934, and their mutual admiration deepened after George Washington Carver made a visit to Michigan in 1937. As Douglas Brinkley writes in ''Wheels for the World'',<ref>{{Cite book |last=Brinkley |first=Douglas |url=https://cmc.marmot.org/Record/.b21749760 |title=Wheels for the world : Henry Ford, his company, and a century of progress, 1903-2003 / |date=2003 |publisher=Viking |isbn=978-0-670-03181-8}}</ref> his history of Ford, the automaker donated generously to the Tuskegee Institute, helping finance Carver's experiments, and Carver in turn spent a period of time helping to oversee crops at the Ford plantation in Ways, Georgia.

By the time World War II began, Ford had made repeated journeys to Tuskegee to convince George Washington Carver to come to Dearborn and help him develop a synthetic rubber to help compensate for wartime rubber shortages. Carver arrived on July 19, 1942, and set up a laboratory in an old water works building in Dearborn. He and Ford experimented with different crops, including sweet potatoes and dandelions, eventually devising a way to make the rubber substitute from goldenrod, a plant weed commercially viable.<ref>{{cite web|url=http://www.history.com/this-day-in-history/george-washington-carver-begins-experimental-project-with-henry-ford|title=George Washington Carver Begins Experimental Project with Henry Ford – Jul 19, 1942 |author=|date=13 November 2009 |publisher=History (U.S. TV channel)|access-date=20 May 2015}}</ref> Carver died in January 1943, Ford in April 1947, but the relationship between their two institutions continued to flourish: As recently as the late 1990s, Ford awarded grants of $4 million over two years to the George Washington Carver School at Tuskegee.<ref>{{Cite web |title=George Washington Carver |url=https://www.acs.org/content/acs/en/education/whatischemistry/landmarks/carver.html |access-date=2022-06-13 |website=American Chemical Society |language=en}}</ref>

Extensive process development was conducted during World War II to commercialize goldenrod as a source of rubber.<ref>{{cite web |url=https://search.nal.usda.gov/discovery/search?query=lds35,contains,CAT30868499-01nal_inst,AND&tab=LibraryCatalog&search_scope=MyInstitution&vid=01NAL_INST:MAIN&mode=advanced&offset=0|title=Extraction, Characterization, and Utilization of Goldenrod Rubber|publisher=US Department of Agriculture|date=9 September 1944|access-date=27 Sep 2011}}</ref> The rubber is only contained in the leaves, not the stems or blooms.<ref>{{Cite journal |title=What Is Natural Rubber and Why Are We Searching for New Sources? |year=2019 |language=en |doi=10.3389/frym.2019.00100|doi-access=free |last1=Arias |first1=Marina |last2=Van Dijk |first2=Peter J. |journal=Frontiers for Young Minds |volume=7 |article-number=100 }}</ref> Typical rubber content of the leaves is 7%. The resulting rubber is of low molecular weight, resulting in an excessively tacky compound with poor tensile properties.<ref>{{Cite web |title=weakest rubber compounds: Topics by Science.gov |url=https://www.science.gov/topicpages/w/weakest+rubber+compounds |access-date=2022-06-13 |website=www.science.gov |language=en}}</ref>

===Traditional medicine=== ''Solidago virgaurea'' is used in a traditional kidney tonic by practitioners of herbal medicine to counter inflammation and irritation caused by bacterial infections or kidney stones.<ref>{{cite journal | pmid = 15638071 |date=November 2004 | author = Melzig, M. F. | title = Goldenrod – a Classical Exponent in the Urological Phytotherapy | volume = 154 | issue = 21–22 | pages = 523–527 | issn = 0043-5341 | journal = Wiener Medizinische Wochenschrift | doi = 10.1007/s10354-004-0118-4|s2cid=20348306 }}</ref><ref name="campion" >Campion, K. (1995). ''Holistic Woman's Herbal – How to Achieve Health and Well-Being at Any Age''. Barnes & Noble, Inc. 1995. pp. 65, 96. {{ISBN|978-0-7607-1030-2}}</ref> Goldenrod is also used in some formulas for cleansing of the kidney or bladder during a healing fast, in conjunction with potassium broth and specific juices.<ref name="campion" /> Some Native American cultures traditionally chew the leaves to relieve sore throats, and the roots to relieve toothaches.<ref name="Silverthorne2002">{{cite book|author=Silverthorne, E.|title=Legends and Lore of Texas Wildflowers|url=https://books.google.com/books?id=w_hKCayJzOoC&pg=PA61|access-date=4 October 2010|year=2002|publisher=Texas A&M University Press|isbn=978-1-58544-230-0|pages=61–}}</ref>

===Medicinal exploration=== In various assessments by the European Medicines Agency with respect to ''Solidago virgaurea'', non-clinical data shows diuretic, anti-inflammatory, antioxidant, analgesic and spasmolytic, antibacterial, antifungal, anticancer and immunomodulatory activity. However, as no single ingredient is responsible for these effects, the whole herbal preparation of ''Solidago'' inflorescences must be considered as the active ingredient.<ref>European Medicines Agency, ''Assessment Report on ''Solidago Virgaurea'' L., Herba'', European Medicines Agency Evaluation of Medicines for Human Use London, 4 September 2008 [https://www.ema.europa.eu/en/documents/herbal-report/assessment-report-solidago-virgaurea-l-herba_en.pdf Doc. Ref. EMEA/HMPC/285759/2007]</ref>

==Cultural significance== The goldenrod is the state flower of the U.S. states of Kentucky (adopted 1926) and Nebraska (adopted 1895). ''Solidago altissima'', tall goldenrod, was named the state wildflower of South Carolina in 2003.<ref>{{Cite web|title=Tall Goldenrod - South Carolina State Wildflower|url=https://www.sciway.net/facts/goldenrod-sc-state-wildflower.html|access-date=2021-05-01|website=www.sciway.net}}</ref> The sweet goldenrod (''Solidago odora'') is the state herb of Delaware.<ref>[https://delcode.delaware.gov/title29/c003/index.html State Seal, Song and Symbols of Delaware]</ref> Goldenrod was the state flower of Alabama, but it was later rejected in favor of the camellia.<ref>{{Cite web |last=Wilson |first=Sue |date=2016-05-07 |title=Remember when: Camellia wasn't always our state flower |url=https://m.andalusiastarnews.com/2016/05/07/camellia-wasnt-always-our-state-flower/ |access-date=2022-06-13 |website=The Andalusia Star-News |language=en}}</ref>

===Accepted species=== Source<ref name=hymenocallis>[http://www.theplantlist.org/tpl1.1/search?q=Solidago The Plant List, search for ''Solidago'']</ref>{{better source needed|reason=Searches are volatile and poorly verifiable. Better to cite individual species using a named source for that specific species|date=May 2022}} *''Solidago albopilosa'' E.L.Braun – whitehair goldenrod *''Solidago altiplanities'' C.E.S. Taylor & R.J.Taylor – high plains goldenrod *''Solidago altissima'' L. – Canada goldenrod, late goldenrod *''Solidago amplexicaulis'' Torr. & A.Gray *''Solidago arenicola'' B.R. Keener & Kral – southern racemose goldenrod *''Solidago argentinensis'' López Laphitz, Rita María & Semple *''Solidago arguta'' Ait. – Atlantic goldenrod, forest goldenrod, toothed goldenrod, cut-leaf goldenrod *''Solidago aurea'' Spreng. *''Solidago auriculata'' Shuttlw. ex Blake – eared goldenrod, clasping goldenrod *''Solidago bartramiana'' Fernald *''Solidago bicolor'' L. – white goldenrod, silverrod *''Solidago brachyphylla'' Chapman – Dixie goldenrod *''Solidago brendiae'' Semple *''Solidago buckleyi'' Torr. & Gray – Buckley's goldenrod *''Solidago caesia'' L. – wreath goldenrod, axillary goldenrod, bluestem goldenrod, woodland goldenrod *''Solidago calcicola'' (Fernald) Fernald *''Solidago californica'' Nutt. - California goldenrod *''Solidago canadensis'' L. – Canada goldenrod, Canadian goldenrod, common goldenrod *''Solidago capulinensis'' Cockerell & Andrews L. – Capulin goldenrod *''Solidago chilensis'' Meyen *''Solidago compacta'' Turcz. *''Solidago confinis'' A.Gray *''Solidago coreana'' (Nakai) H.S.Pak *''Solidago correllii'' Semple L. – Guadalupe Mountains goldenrod *''Solidago curtisii'' Torr. & A.Gray – mountain decumbent goldenrod, Curtis' goldenrod *''Solidago dahurica'' (Kitagawa) Kitagawa ex Juzepczuk *''Solidago decurrens'' Loureiro *''Solidago delicatula'' Small – elmleaf goldenrod, smooth elm-leaf goldenrod *''Solidago drummondii'' Torr. & A.Gray. – Drummond's goldenrod *''Solidago durangensis'' G.L.Nesom *''Solidago elongata'' Nutt. – West Coast Canada goldenrod, Cascade Canada goldenrod *''Solidago erecta'' Nutt. – showy goldenrod, slender goldenrod *''Solidago ericamerioides'' G.L.Nesom *''Solidago faucibus'' Wieboldt – gorge goldenrod *''Solidago fistulosa'' P.Mill. – pine-barren goldenrod *''Solidago flexicaulis'' L. – zigzag goldenrod, broadleaf goldenrod *''Solidago gattingeri'' Chapman – Gattinger's goldenrod *''Solidago gigantea'' Ait. – giant goldenrod, tall goldenrod, early goldenrod, smooth goldenrod *''Solidago glabra'' Desf. *''Solidago glomerata'' Michx. – clustered goldenrod, skunk goldenrod *''Solidago guiradonis'' A.Gray – Guirado's goldenrod *''Solidago gypsophila'' G.L.Nesom *''Solidago hintoniorum'' G.L.Nesom *''Solidago hispida'' Muhl. ex Willd. – hairy goldenrod *''Solidago houghtonii'' Torr. & A.Gray ex A.Gray – Houghton's goldenrod *''Solidago humilis'' Mill. *''Solidago inornata'' Lunell *''Solidago juliae'' G.L.Nesom – Julia's goldenrod *''Solidago juncea'' Ait. – early goldenrod *''Solidago kralii'' Semple – Kral's goldenrod *''Solidago kuhistanica'' Juz. *''Solidago kurilensis'' Juz. *''Solidago lancifolia'' Torr. & A.Gray – lance-leaf goldenrod *''Solidago latissimifolia'' P.Mill. – Elliott's goldenrod *''Solidago leavenworthii'' Torr. & A.Gray – Leavenworth's goldenrod *''Solidago leiocarpa'' DC. in DC. &. A.DC. – Cutler's alpine goldenrod *''Solidago lepida'' DC. – western Canada goldenrod *''Solidago ludoviciana'' (Gray) Small – Louisiana goldenrod *''Solidago macrophylla'' Pursh – largeleaf goldenrod *''Solidago macvaughii'' G.L.Nesom *''Solidago microglossa'' DC. *''Solidago minutissima'' (Makino) Kitam. *''Solidago missouriensis'' Nutt. – Missouri goldenrod, prairie goldenrod, Tolmie's goldenrod *''Solidago mollis'' Bartl. – velvety goldenrod, soft goldenrod, woolly goldenrod *''Solidago multiradiata'' Ait. – Rocky Mountain goldenrod, alpine goldenrod, northern goldenrod, manyray goldenrod *''Solidago nana'' Nutt. – baby goldenrod, dwarf goldenrod, gray goldenrod *''Solidago nemoralis'' Ait. – gray goldenrod, dyersweed goldenrod, old-field goldenrod *''Solidago nitida'' Torr. & A.Gray – shiny goldenrod *''Solidago odora'' Ait. – anise-scented goldenrod, sweet goldenrod, fragrant goldenrod *''Solidago ohioensis'' Riddell – Ohio goldenrod *''Solidago orientalis'' G.L.Nesom *''Solidago ouachitensis'' C.E.S.Taylor & R.J.Taylor – Ouachita Mountains goldenrod *''Solidago ovata'' Friesner *''Solidago pacifica'' Juzepczuk *''Solidago paniculata'' DC. *''Solidago patagonica'' Phil. *''Solidago patula'' Muhl. ex Willd. – roundleaf goldenrod, roughleaf goldenrod *''Solidago petiolaris'' Ait. – downy ragged goldenrod *''Solidago perornata'' Lunell *''Solidago pilosa'' Mill. *''Solidago pinetorum'' Small – Small's goldenrod *''Solidago plumosa'' Small – plumed goldenrod, plumose goldenrod, Yadkin River goldenrod *''Solidago pringlei'' Fernald *''Solidago procera'' Aiton *''Solidago ptarmicoides'' (Torr. & A.Gray) B.Boivin – white flat-top goldenrod, upland white aster *''Solidago puberula'' Nutt. – downy goldenrod *''Solidago pulchra'' Small – Carolina goldenrod *''Solidago radula'' Nutt. – western rough goldenrod *''Solidago riddellii'' Frank ex Riddell – Riddell's goldenrod *''Solidago rigida'' L. – rigid goldenrod, stiff-leaf goldenrod *''Solidago roanensis'' Porter – Roan Mountain goldenrod *''Solidago rugosa'' P.Mill. – wrinkleleaf goldenrod, rough-stemmed goldenrod *''Solidago rupestris'' Raf. – rock goldenrod *''Solidago satanica'' Lunell *''Solidago sciaphila'' Steele – shadowy goldenrod *''Solidago sempervirens'' L. – seaside goldenrod, salt-marsh goldenrod *''Solidago serotina'' Retz. *''Solidago shortii'' Torr. & A.Gray – Short's goldenrod *''Solidago simplex'' Kunth : Mt. Albert goldenrod, sticky goldenrod *''Solidago spathulata'' DC. – coast goldenrod *''Solidago speciosa'' Nutt. – showy goldenrod, noble goldenrod *''Solidago spectabilis'' (D.C.Eat.) A.Gray – Nevada goldenrod, basin goldenrod *''Solidago sphacelata'' Raf. – autumn goldenrod, false goldenrod *''Solidago spithamaea'' M.A.Curtis – Blue Ridge goldenrod, skunk goldenrod *''Solidago spiraeifolia'' Fisch. ex Herder *''Solidago squarrosa'' Nutt. – stout goldenrod *''Solidago stricta'' Ait. – wand goldenrod, willow-leaf goldenrod *''Solidago tarda'' Mack. – Atlantic goldenrod *''Solidago tortifolia'' Ell. – twistleaf goldenrod *''Solidago uliginosa'' Nutt. – bog goldenrod, fall goldenrod *''Solidago ulmifolia'' Muhl. ex Willd. – elmleaf goldenrod *''Solidago velutina'' DC. – threenerve goldenrod, velvety goldenrod *''Solidago verna'' M.A.Curtis – springflowering goldenrod *''Solidago villosicarpa'' LeBlond – glandular wand goldenrod, hairy-seed goldenrod *''Solidago virgaurea'' L. – European goldenrod *''Solidago vossii'' J.S.Pringle & Laureto – Voss's goldenrod *''Solidago wrightii'' A.Gray – Wright's goldenrod *''Solidago yokusaiana'' Makino

===Natural hybrids=== *''Solidago'' × ''asperula'' Desf. (''S. rugosa'' × ''S. sempervirens'')<ref name=hymenocallis/> *''Solidago'' × ''beaudryi'' Boivin (''S. rugosa'' × ''S. uliginosa'')<ref name=hymenocallis/> *''Solidago'' × ''calcicola'' (Fernald) Fernald – limestone goldenrod<ref name=hymenocallis/> *''Solidago'' × ''erskinei'' Boivin (''S. canadensis'' × ''S. sempervirens'')<ref name=hymenocallis/> *''Solidago'' × ''niederederi''<ref name="EPPO-GD-niederederi" /><ref name="CABI-ISC-niederederi" /><ref name="Skokanova-et-al-2020" /><ref name="Pliszko-et-al-2017" /> Khek<ref name="CABI-ISC-niederederi" /><ref name="Skokanova-et-al-2020" /><ref name="Pliszko-et-al-2017" /> (''S. canadensis'' × ''S. virgaurea'')<ref name="EPPO-GD-niederederi" /><ref name="Skokanova-et-al-2020" /><ref name="Pliszko-et-al-2017" /> *''Solidago'' × ''ovata'' Friesner (''S. sphacelata'' × ''S. ulmifolia'')<ref name=hymenocallis/> *''Solidago'' × ''ulmicaesia'' Friesner (''S. caesia'' × ''S. ulmifolia'')<ref name=hymenocallis/>

===Formerly included=== Numerous species formerly considered members of ''Solidago'' are now regarded as better suited to other genera, including ''Brintonia'', ''Duhaldea'', ''Euthamia'', ''Gundlachia'', ''Inula'', ''Jacobaea'', ''Leptostelma'', ''Olearia'', ''Psiadia'', ''Senecio'', ''Sphagneticola'', ''Symphyotrichum'', and ''Trixis''.<ref name=hymenocallis/>

==References== {{Reflist|30em|refs=

<ref name="CABI-ISC-niederederi">{{cite web | title=''Solidago'' × ''niederederi'' | website=Invasive Species Compendium (ISC) | publisher=CABI (Centre for Agriculture and Bioscience International) | date=2019-11-19 | url=http://www.cabi.org/ISC/datasheet/120068 | access-date=2021-02-22}}</ref>

<ref name="Skokanova-et-al-2020">{{cite journal | last1=Skokanová | first1=Katarína | last2=Šingliarová | first2=Barbora | last3=Španiel | first3=Stanislav | last4=Hodálová | first4=Iva | last5=Mereďa | first5=Pavol | title=Tracking the Expanding Distribution of ''Solidago'' ×''niederederi'' (Asteraceae) in Europe and First Records from Three Countries Within the Carpathian Region | journal=BioInvasions Records | publisher=Regional Euro-Asian Biological Invasions Centre Oy (REABIC) | volume=9 | issue=4 | year=2020 | issn=2242-1300 | doi=10.3391/bir.2020.9.4.02 | pages=670–684| doi-access=free }}</ref>

<ref name="EPPO-GD-niederederi">{{cite journal | title=Updated Distribution of ''Solidago'' x ''niederederi'' in Poland | publisher=European and Mediterranean Plant Protection Organization (EPPO) | date=2018-12-11 | url=http://gd.eppo.int/reporting/article-6259 | journal=EPPO Reporting Service | volume=03 - 2018 | number=2018/065 | access-date=2021-02-22}}</ref>

<ref name="Pliszko-et-al-2017">{{cite journal | last1=Pliszko | first1=Artur | last2=Łazarski | first2=Grzegorz | last3=Kalinowski | first3=Paweł | last4=Adamowski | first4=Wojciech | last5=Rutkowski | first5=Lucjan | last6=Puchałka | first6=Radosław | title=An Updated distribution of ''Solidago'' × ''niederederi'' (Asteraceae) in Poland | journal=Acta Musei Silesiae, Scientiae Naturales | publisher=Walter de Gruyter GmbH | volume=66 | issue=3 | date=2017-12-20 | issn=2336-3207 | doi=10.1515/cszma-2017-0026 | pages=253–258| doi-access=free }}</ref>

}}

==External links== *{{Commons category-inline|Solidago}} *{{Wikispecies-inline|Solidago}} *[http://www.ontariowildflower.com/goldenrods.htm Goldenrod identification.] Andy's Northern Ontario Wildflowers. *[http://ontariowildflowers.com/main/group.php?id=2 Goldenrods Group.] Ontario Wildflowers. *[http://www.jcsemple.uwaterloo.ca/goldenrods.htm ''Solidago'': Goldenrods.] Astereae Lab. University of Waterloo (Canada).

Category:Solidago Category:Asteraceae genera Category:Botanical taxa named by Carl Linnaeus Category:Plant dyes