John C. Semple WAT

Solidago L.: Goldenrods

Goldenrods are members of the genus Solidago L. (Compositae: Astereae), which includes about 100 species of North American wildflowers and more than a dozen species native South America, Europe and Asia. The latter are derived from North American taxa. All species are herbaceous perennials ranging from 5 cm to 2 m tall. These usually have small heads with yellow pistillate ray and perfect disc florets aggregated into flat-topped, wand-shaped or pyramidal inflorescences. The phyllaries are generally lanceolate to ovate, present in 2-4 graduated series, and have a translucent midrib. All goldenrods have a chromosome base number of x=9 and many include several different ploidy levels. The genus was once thought to include the Grass-leaved Goldenrods, but these belong in the genus Euthamia Nutt., with about seven species native to eastern North America and one native to western North America. Studies based on chloroplast DNA restriction fragment length polymorphisms clearly show that Solidago is related to Chrysoma native to the southeastern United States, Oreochrysum, Chrysothamnus, Petradoria, Tonestus and Hesperadoria) native to western North America (Lane et al. 1996; Zhang 1996, Ph.D., U.Waterloo; Brouillet et al. 2001a,b; Beck et al., pers. comm.) and Bigelowia native to the southeastern United States.The white-rayed "aster" genus Sericocarpus is also related to goldenrods. Euthamia is not as closely related to Solidago as these genera.

The monotypic genus Brintonia E.L. Greene has been sometimes included in Solidago (e.g., Nesom 1993) and sometimes not (e.g. Cronquist 1980). During preparation of the treatments of the goldenrods for Flora North America (Semple 2006; Semple and Cook 2008), B. discoidea was found to be sufficiently different in involucre, floret and pappus traits to be excluded from Solidago. DNA sequence studies also indicate Brintonia does not belong within Solidago but is closely related (Beck et al., 2004).

Zhang (1996, Ph.D.; summarized in Semple, et al. 1999) showed that the flat-topped goldenrods (S. sect. Corymbosae; treated as the genus Oligoneuron by some authors) were nested within other lines of goldenrods included in Solidago by all recent authors. A cladistic analysis based on goldenrod morphology reached the same conclusion (Semple and Duc Minh Le, unpublished honors thesis). Recent DNA sequence studies indicated the there is a very low level of variation (< 1%) in ITS and other sequences within Solidago (Shilling et al. 2008).

Goldenrods are sometimes treated unkindly.

Goldenrods do not cause hayfever! Ragweed, Ambrosia spp., does; it has inconspicuous green flowers and blooms at the same time as the insect-pollinated, showy-flowered goldenrods.

Systematics and Some Illustrations of Goldenrods

Publications on goldenrods by John C. Semple

Brouillet, L. and J.C. Semple. 1981. A propos du status taxonomique de Solidago ptarmicoides (Nees) Boivin. Canad. J. Bot. 58: 17-21.

Semple, J.C., R. A. Brammall and J.G. Chmielewski. 1981. Chromosome numbers of goldenrods, Euthamia and Solidago, (Compositae-Astereae) Canad. J. Bot. 59: 1167-1173.

Semple, J.C. and G. Ringius. 1983. The goldenrods of Ontario: Solidago L. and Euthamia Nutt. Univ. Waterloo Biol. Ser. 26: 1-84.

Semple, J.C. and G. Ringius. 1983. Treatment of Solidago. In: G.W. Argus and D.J. White, eds. Atlas of the rare vascular plants of Ontario. Part 2. National Museums of Canada, Ottawa.

Semple, J.C., G. Ringius, C. Leeder and G. Morton. 1984. Chromosome number of goldenrods, Euthamia and Solidago (Compositae-Astereae). II. Additional counts with comments on cytogeography. Brittonia 36: 280-292. Erratum. 37: 121.

Semple, J.C. 1985a. Chromosome number determinations in Fam. Compositae tribe Astereae. Rhodora 87: 517-527.

Chmielewski, J. and J.C. Semple. 1985b. The cytogeography and post glacial migration of Solidago flexicaulis (Compositae) in southern Ontario. Naturaliste Canadien 112: 307-311.

Semple, J.C. 1985c. New names and combinations in Astereae. Phytologia 58: 429-431.

Chmielewski, J.G., R.S. Ringius and J.C. Semple. 1987. The cytogeography of Solidago uliginosa Nutt. (Compositae: Astereae) in the Great Lakes region. Canad. J. Bot. 65: 1045-1046.

Ringius , G. S. and J.C. Semple. 1987. Cytogeography of the Solidago spathulata -- glutinosacomplex (Compositae: Astereae). Canad. J. Bot. 65: 2458-2462.

Semple, J.C. and J.G. Chmielewski. 1987. Chromosome numbers in Fam. Compositae, Tribe Astereae. II. Additional Counts. Rhodora 89: 319-325.

Brunton, D. F., and J.C. Semple. 1987. Treatment of Solidago nemoralis ssp. decemflora. In: G.W. Argus, K. Pryer, D. White, and C. J. Keddy, eds. Atlas of the rare vascular plants of Ontario. Fascicle 4. National Museums of Canada, Ottawa.

Heard, S.B. and J.C. Semple. 1988. The Solidago rigida complex (Compositae: Astereae): a multivariate morphometric analysis and chromosome numbers. Canad. J. Bot. 66: 1800-1807.

Chmielewski, J.G., J.C. Semple, L.M. Burr, and W.R. Hawthorn. 1989. Comparison of achene characteristics within and among diploid and tetraploid clones of Solidago flexicaulis and their significance in germination and resource allocation studies. Canad. J. Bot. 67: 1821-1832.

Semple, J.C. and J. G. Chmielewski, AND M. Lane. 1989. Chromosome numbers in Fam. Compositae, Tribe Astereae. III. Additional counts and comments on some generic limits limits and ancestral base numbers. Rhodora 91: 296-314.

BrammallL, R.A. and J.C. Semple. 1990. The cytotaxonomy of Solidago nemoralis (Compositae: Astereae). Canad. J. Bot. 68: 2065-2069.

Semple, J.C., J.G. Chmielewski, and R.A. Brammall. 1990. A multivariate study of Solidago nemoralis (Compositae: Astereae) and comparison with S. californica and S. sparsiflora. Canad. J. Bot. 68: 2070-2082.

Ringius, G.S. and J.C. Semple. 1991. New combinations in Solidago simplex (Compositae: Astereae). Phytologia 70: 396-399.

Semple, J.C. 1992. A geographic summary of chromosome number reports for North American asters and goldenrods (Compositae: Astereae). Ann. Missouri Bot. Garden 79: 95-109. [Based on invited paper presented at the W.H. Lewis Tribute Symposium, St. Louis, 7 Oct 1990]

Semple, J.C., J.G. Chmielewski, and ChunSheng Xiang. 1992. Chromosome numbers in Fam. Compositae, Tribe Astereae. IV. Additional reports and comments on the cytogeography and status of some species of Aster and Solidago. Rhodora 94: 48-62.

Semple, J.C. 1992. The goldenrods of Ontario: Solidago L. and Euthamia Nutt. Revised Edition. Univ. Waterloo Biol. Ser. 36: 1-82.

Semple, J.C., Jie Zhang and ChunSheng Xiang. 1993. Chromosome numbers in Fam. Compositae, Tribe Astereae. V. Eastern North American taxa. Rhodora 95: 234-253.

Semple, J.C., G.S. Ringius and Jie Zhang. 1999. The goldenrods of Ontario: Solidago L. and Euthamia Nutt. 3rd Edition. Univ. Waterloo Biol. Ser. 39: 1-90. [abstract]

Semple, J.C., ChunSheng Xiang, Jie Zhang, M. Horsburgh and R.E. Cook. 2001. Chromosome number determinations in Fam. Compositae, Tribe Astereae. VI. Western North American taxa and comments on generic treatments of North American asters. Rhodora 103: 202-218.

Hood, J.L.A. and J.C. Semple. 2003. Pappus variation in Solidago (Asteraceae: Astereae). Sida 20(4): 1617–1630. [abstract]

Semple, J.C. 2003. New names and combinations in Solidago (Asteraceae: Astereae). Sida 20(4): 1605–1616. [abstract]

Wieboldt, T.F. and J.C. Semple. 2003. Solidago fauciba (Asteraceae: Astereae), a new mesic forest goldenrod from the Appalachian Mountains. Sida 20(4): 1605–1616. [abstract]

Cook, R.E. and J.C. Semple. 2004. A new name and a new combination in Solidago subsect. Glomeruliflorae (Asteraceae: Astereae). Sida 21: 221-224.

Semple, J.C.,and R.E. Cook. 2004. Chromosome numbers in Fam. Compositae, Tribe Astereae. VII. Some eastern North American and Eurasian taxa. Rhodora 106: 253-272.

Semple, J.C. 2004. Miscellaneous nomenclatural changes in Astereae (Asteraceae). Sida 21(2): 759-765.

Semple, J.C. 2006. Brintonia E.L. Greene. pp. 106. In Flora North America Editorial Committee, eds. Flora of North America. Vol. 20. Asteraceae, Part. 2. Astereae and Senecioneae. Oxford University Press.

Semple, J.C. and R.E. COOK. 2006. Solidago. pp. 107-166. In Flora North America Editorial Committee, eds. Flora of North America. Vol. 20. Asteraceae, Part. 2. Astereae and Senecioneae. Oxford University Press.

Semple, J.C. 2007. (1775) Proposal to conserve the name Solidago elongata Nutt. against S. elongata Pépin (Compositae). Taxon 56: 605-606.

Schlaepfer, D.R., P.J. Edwards, J.C. Semple, and R. Billeter. 2008. Cytogeography of Solidago gigantea Ait. (Asteraceae) and its invasive ploidy level. J. Biogeography 35: 2119-2127.

Cook, R.E. and J.C. Semple. 2008. The cytogeography of Solidago subsect. Glomeruliflorae (Asteraceae: Astereae). Botany 86: 1488-1496.

Semple, J.C. and K. Watanabe. 2008, in press. Chapter 4. A review of chromosome numbers in the Asteraceae with hypotheses on chromosomal base number evolution. Pp. 21-32. In Systematics, Evolution and Biogeography of the Compositae, Funk, V.A., A. Susanna, T. Stuessy, and R. Bayer (eds.). IAPT, Vienna, Austria.

Brouillet, L., T. Lowrey, L. Urbatsch, V. Karaman-Castro, G. Sancho, S. Wagstaff, and J.C. Semple. 2009, in press. Chapter 37. Phylogeny and evolution of the Astereae (Compositae or Asteraceae). Pp. 449-490. In Systematics, Evolution and Biogeography of the Compositae, Funk, V.A., A. Susanna, T. Stuessy, and R. Bayer (eds.). IAPT, Vienna, Austria.

Cook, R.E., J.C. Semple and B. Baum. 2009. A multivariate morphometric study of Solidago subsect. Glomeruliflorae (Asteraceae: Astereae). Botany. 87: 97-111.