Abstract
A new subgenus, Sonchus subg. Palustres, is established to accommodate S. erzincanicus endemic to Turkey and former Sonchus ser. Palustres including S. palustris and S. sosnowskyi. Although the exclusive placement of S. palustris has already been documented by previous studies based on molecular phylogenetic analyses without morphological evidence, there has not been any study of S. erzincanicus above the specific level. The present study proposes a new subgenus based on chiefly molecular data, and contribute macro- and micro-morphological features (i.e. pollen grains and achenes) of the studied species together with the phylogenetic position based on nrITS and matK with multiple sampling. Further literature and morphological studies evidently showed that S. erzincanicus and S. palustris have slightly heteromorphic achenes which is a subtle character and underestimated up to now in the infrageneric classification of the genus Sonchus. Besides, the molecular analyses revealed that S. erzincanicus and S. palustris are sister taxa, forming an exclusive clade of their own within the genus. Moreover, the Palustres clade is the first diverged one among the clades of the genus Sonchus based on the nrITS
data. Consequently, S. erzincanicus, S. palustris and S. sosnowskyi are treated as members of the suggested new subgenus. Therefore, the slightly heteromorphic achene feature could be taken into consideration for species delimitation in the genus Sonchus as a supportive morphological character. Furthermore, S. araraticus is suggested as a synonym of S. erzincanicus based on its morphological and ecological characteristics.
References
<p>Aslay, M. & Kandemir, A. (2009) The Study of Conservation of <em>Sonchus erzincanicus</em> Matthews (Asteraceae). <em>Fen Bilimleri Enstitüsü Dergisi</em> 2 (1): 1–15.</p>
<p>Babcock, E.B. (1947) <em>The genus Crepis, Part 1: the taxonomy, phylogeny, distribution and evolution of Crepis</em>. University of California Publications in Botany, Berkeley-Los Angeles, 198 pp.</p>
<p>Barthlott, W. (1981) Epidermal and Seed Surface Characters of Plants: Systematic Applicability and Some Evolutionary Aspects. <em>Nordic Journal of Botany</em> 3: 345–355. https://doi.org/10.1111/j.1756-1051.1981.tb00704.x</p>
<p>Blattner, F.R. (1999) Direct amplification of the entire ITS region from poorly preserved plant material using recombinant PCR. <em>Biotechniques </em>27: 1180–1186. https://doi.org/10.2144/99276st04</p>
<p>Boulos, L. (1960) Cytotaxonomic studies in the genus <em>Sonchus</em> 2. The genus <em>Sonchus</em>, a general treatment. <em>Botaniska Notiser</em> 113: 400–420.</p>
<p>Boulos, L. (1972) Révision systématique du genre <em>Sonchus</em> L. s.l. I. Introduction et classification. <em>Botaniska Notiser</em> 125: 287–305.</p>
<p>Boulos, L. (1973) Révision systématique du genre <em>Sonchus</em> L. s.l. IV. Sousgenre 1. <em>Sonchus</em>. <em>Botaniska Notiser</em> 126: 155–196.</p>
<p>Boulos, L. (1974) Révision systématique du genre <em>Sonchus</em> L. s.l. VI. Sousgenre 3. Origosonchus. Genres Embergeria, Babcockia et Taeckholmia. <em>Botaniska Notiser</em> 127: 402–451.</p>
<p>Bremer, K. (1994) <em>Asteraceae: Cladistics and classification</em>. Timber Press, Portland, Oregon, 752 pp.</p>
<p>Cho, M.-S., Kim, S.-H., Yang, J.Y., Crawford, D.J., Stuessy, T.F., López-Sepúlveda, P. & Kim, S.-C. (2020) Plastid phylogenomics of <em>Dendroseris (Cichorieae; Asteraceae)</em>: insights into structural organization and molecular evolution of an endemic lineage from the Juan Fernández Islands. <em>Frontiers in Plant Science</em> 11: e594272. https://doi.org/10.3389/fpls.2020.594272</p>
<p>Cunningham, C.W. (1997) Can three incongruence tests predict when data should be combined? <em>Molecular Biology and Evolution</em> 14: 733–740. https://doi.org/10.1093/oxfordjournals.molbev.a025813</p>
<p>Diez, M.J. & Meijas, J.A. & Moreno-Socías, E. (1999) Pollen morphology of <em>Sonchus</em> and related genera, and a general discussion. <em>Plant Systematics and Evolution</em> 214: 91–102. https://doi.org/10.1007/BF00985733</p>
<p>Doyle, J.J. & Doyle, J.L. (1987) A rapid DNA Isolation Procedure for Small Quantities of Fresh Leaf Tissue. <em>Phytochemical Bulletin</em> 19: 11–15.</p>
<p>Edgar, R.C. (2004) MUSCLE: Multiple Sequence Alignment with High Accuracy and High Throughput. <em>Nucleic Acids Research</em> 32: 1792–1797. https://doi.org/10.1093/nar/gkh340</p>
<p>Enke, N. & Gemeinholzer, B. (2008) Babcock revisited: new insights into generic delimitation and character evolution in <em>Crepis</em> L. (Compositae: Cichorieae) from ITS and <em>mat</em>K sequence data. <em>Taxon</em> 57: 756–768. https://doi.org/10.1002/tax.573008</p>
<p>Erdtman, G. (1952) <em>Pollen Morphology and Plant Taxonomy</em>. Almqvist and Wiksells, Uppsala, pp. 133–134. https://doi.org/10.1080/11035895209453507</p>
<p>Farris, J.S., Källersjö, M., Kluge, A.G. & Bult, C. (1994) Testing significance of congruence. <em>Cladistics</em> 10: 315–319. https://doi.org/10.1111/j.1096-0031.1994.tb00181.x</p>
<p>Fehrer, J., Gemeinholzer, B., Chrtek, J. & Bräutigam, S. (2007) Incongruent plastid and nuclearDNA phylogenies reveal ancient intergeneric hybridization in <em>Pilosella</em> hawkweeds (<em>Hieracium</em>, Cichorieae, Asteraceae). <em>Molecular Phylogenetics and Evolution</em> 42: 347–361. https://doi.org/10.1016/j.ympev.2006.07.004</p>
<p>Jeffrey, C. (1966) Notes on Compositae: I. The Cichorieae in east tropical Africa. <em>Kew Bulletin</em> 18: 427–486. https://doi.org/10.2307/4115797</p>
<p>Johnson, L. & Soltis, D. (1995) Phylogenetic Inference in Saxifragaceae Sensu Stricto and Gilia (Polemoniaceae) Using matK Sequences. <em>Annals of the Missouri Botanical Garden</em> 82 (2): 149–175. https://doi.org/10.2307/2399875</p>
<p>JSTOR (2000) [continuously updated] Global Plants. Available from: http://plants.jstor.org (accessed 29 June 2021)</p>
<p>Kandemir, A., Makbul, S., Türkme, Z. & Yılmaz, M. (2006) Morphological, Anatomical and Palynological Investigation on <em>Sonchus erzincanicus</em> Matthews (Asteraceae). <em>Turkish Journal of Botany</em> 30: 405–411.</p>
<p>Kavak, S. (2014) <em>Sonchus erzincanicus</em>. The IUCN Red List of Threatened Species e.T19617539A19620981.</p>
<p>Kilian, N. (1997) Revision of <em>Launaea</em> Cass. (Compositae, Lactuceae, Sonchinae). <em>Englera</em> 17: 1–448. https://doi.org/10.2307/3776755</p>
<p>Kilian, N., Gemeinholzer, B. & Lack, H.W. (2009a) Tribe Cichorieae. <em>In</em>: Funk, V.A., Susanna, A., Steussy, T.F. & Bayer, R.J. (Eds.) <em>Systematics, Evolution, and Biogeography of Compositae</em>. IAPT, Vienna, pp. 343–383.</p>
<p>Kilian, N., Hand, R. & Raab-Straube, E von (Eds.) (2009b) [continuously updated] <em>Cichorieae Systematics Portal</em>. Available from: http://cichorieae.etaxonomy.net/portal/ (accessed 29 June 2021)</p>
<p>Kim, S.-C., Crawford, D.J., Francisco-Ortega, J. & Santos-Guerra, A. (1996) A common origin for woody <em>Sonchus</em> and five related genera in the Macaronesian islands: molecular evidence for extensive radiation. <em>Proceedings of the National Academy of Sciences of the United States of America</em> 93: 7743–7748. https://doi.org/10.1073/pnas.93.15.7743</p>
<p>Kim, S.-C., Crawford, D.J. & Jansen, R.K. (1997) Phylogenetic relationships among the genera of the subtribe Sonchinae (Asteraceae): evidence from ITS sequences. <em>Systematic Botany</em> 21: 417–432. https://doi.org/10.2307/2419668</p>
<p>Kim, S.-C., Crawford, D.J., Francisco-Ortega, J. & Santos-Guerra, A. (1999a) Adaptive radiation and genetic differentiation in the woody <em>Sonchus</em> alliance (Asteraceae: Sonchinae) in the Canary Islands. <em>Plant Systematics and Evolution</em> 215: 101–118. https://doi.org/10.1007/BF00984650</p>
<p>Kim, S.-C., Crawford, D.J., Jansen, R.K. & Santos-Guerra, A. (1999b) The use of a non-coding region of chloroplast DNA in phylogenetic studies of the subtribe Sonchinae (Asteraceae: Lactuceae). <em>Plant Systematics and Evolution</em> 215: 85–99. https://doi.org/10.1007/BF00984649</p>
<p>Kim, S.-C., Lu, C.T. & Lepschi, B.J. (2004) Phylogenetic positions of Actites megalocarpa and Sonchus hydrophilus (Sonchinae: Asteraceae) based on ITS and chloroplast non-coding DNA sequences. <em>Australian Systematic Botany</em> 17: 73–81. https://doi.org/10.1071/SB03019</p>
<p>Kim, S.-C., Lee, C. & Mejías, J.A (2007) Phylogenetic analysis of chloroplast DNA matK gene and ITS of nrDNA sequences reveals polyphyly of the genus <em>Sonchus</em> and new relationships among the subtribe Sonchinae (Asteraceae: Cichorieae). <em>Molecular Phylogenetics and Evolution</em> 44: 578–597. https://doi.org/10.1016/j.ympev.2007.03.014</p>
<p>Kim, S.-C., Mejías, J.A. & Pesach, L. (2008) Molecular confirmation of the hybrid origin of the critically endangered western Mediterranean endemic <em>Sonchus pustulatus </em>(Asteraceae: Sonchinae). <em>Journal of Plant Research</em> 121: 357–364. https://doi.org/10.1007/s10265-008-0166-8</p>
<p>Kirpicznikov, M.E. (1964a) <em>Sonchus</em> L. <em>In</em>: Bobrov, E.G. & Tzevlev, N.N. (Eds.) <em>Flora of the USSR</em>, vol. 29, Akademiya Nauk SSSR, Moscow, Leningrad, pp. 243–259.</p>
<p>Kirpicznikov, M.E. (1964b) The system of <em>Sonchus</em> as accepted in the Flora of the USSR. <em>Novosti Sistematiki Vysshikh Rastenii</em> 1: 341–342.</p>
<p>Lee, C., Kim, S.-C., Lundy, K. & Santos-Guerra, A. (2005) Chloroplast DNA phylogeny of the woody <em>Sonchus </em>alliance (Asteraceae: Sonchinae) in the Macaronesian Islands. <em>American Journal of Botany</em> 92: 2072–2085. https ://doi.org/10.3732/ajb.92.12.2072</p>
<p>Matthews, V.A. (1974) <em>Sonchus erzincanicus</em> V. A. Matthews. <em>Notes from the Royal Botanic Garden, Edinburgh</em> 33: 429.</p>
<p>Matthews, V.A. (1975) <em>Sonchus</em> L. <em>In</em>: Davis, P.H. (Ed.) <em>Flora of Turkey and the East Aegean Islands</em>, vol. 5. Edinburgh Univ. Press, Edinburgh, pp. 690–693.</p>
<p>Mejías, J.A. (1992) Reproductive biology in the Iberian taxa of the genera <em>Sonchus</em> and <em>Aetheorhiza</em> (Asteraceae: Lactuceae). <em>Flora Mediterranea</em> 2: 15–32.</p>
<p>Mejías, J.A. (2017) <em>Sonchus</em> L. <em>In</em>: Talavera, S., Buira, A., Quintanar, A., García, M.Á., Talavera, M., Fernández Piedra, P. & Aedo, C. (Eds.) <em>Flora Iberica XVI (II), Compositae (partim)</em>. Real Jardín Botánico, CSIC, Madrid, pp. 871–891.</p>
<p>Mejías, J.A. & Kim, S.-C. (2012) Taxonomic treatment of Cichorieae (Asteraceae) endemic to the Juan Fernandez and Desventuradas Islands (SE Pacific). <em>Annales Botanici Fennici</em> 49 (3): 171–178. https://doi.org/10.5735/085.049.0303</p>
<p>Mejías, J.A. & Valdes, B. (1987) Karyological studies in <em>Sonchus</em> section <em>Maritimi</em> (Asteraceae) from the Iberian Peninsula. <em>Botanical Journal of the Linnean Society</em> 98: 61–69.</p>
<p>Mejías, J.A., Chambouleyron, M., Kim, S.H., Infante, M.D., Kim, S.-C. & Léger, J.F. (2018) Phylogenetic and morphological analysis of a new cliff-dwelling species reveals a remnant ancestral diversity and evolutionary parallelism in <em>Sonchus</em> (Asteraceae). <em>Plant Systematics and Evolution</em> 304: 1023–1040. https://doi.org/10.1007/s00606-018-1523-2</p>
<p>Miller, M.A., Pfeiffer, W. & Schwartz, T. (2010) <em>Creating the CIPRES Science Gateway for inference of large phylogenetic trees</em>.<em> In: Proceedings of the Gateway Computing Environments Workshop (GCE), New Orleans, Louisiana, 14 Nov 2010.</em> pp. 45–52. [Piscataway: IEEE] https://doi.org/10.1109/GCE.2010.5676129</p>
<p>Müller, K. (2004) PRAP-Computation of Bremer Support for Large Data Sets. <em>Molecular Phylogenetics and Evolution</em> 31: 780–782. https://doi.org/10.1016/j.ympev.2003.12.006</p>
<p>Müller, K. (2005a) SeqState: Primer design and sequence statistics for phylogenetic DNA datasets. <em>Applied Bioinformatics</em> 4 (1): 65–69. https://doi.org/10.2165/00822942-200504010-00008</p>
<p>Müller, K. (2005b) The efficiency of different search strategies in estimating parsimony jackknife, bootstrap, and Bremer support. <em>BMC Evolutionary Biology</em> 5: 58.</p>
<p>Müller, K., Müller, J. & Quandt, D. (2010) PhyDE: Phylogenetic Data Editor, version 0.9971. Available from: http://www.phyde.de/index.html (accessed 20 January 2022)</p>
<p>Nazarova, E.A. & Barsegyan, A.M. (1983) <em>Sonchus araraticus</em> (Asteraceeae) – A New Species From Armenia. <em>Botanicheskii Zhurnal</em> 68: 950–952.</p>
<p>Nixon, K.C. (1999) The parsimony ratchet, a new method for rapid parsimony analysis. <em>Cladistics</em> 15: 407–414. https://doi.org/10.1111/j.1096-0031.1999.tb00277.x</p>
<p>Nylander, J.A.A. (2004) MrModeltest, version 2. Evolutionary Biology Centre, Uppsala University. [https://www.abc.se/~nylander/mrmodeltest2/mrmodeltest2.html]</p>
<p>Punt, W., Hoen, P.P., Blackmore, S., Nilsson, S. & Thomas, L.A. (2007) Glossary of pollen and spore terminology. <em>Review of Palaeobotany and Palynology</em> 143: 1–81. https://doi.org/10.1016/j.revpalbo.2006.06.008</p>
<p>Ronquist, F., Teslenko, M., Mark, P.V.D., Ayres, D.L., Darling, A., Hohna, S., Larget, B., Liu, L., Suchard, M.A. & Huelsenbeck, J.P. (2012) MrBayes 3.2: efficient Bayesian phylogenetic inference and model choice across a large model space. <em>Systematic Biology</em> 61: 539–542. https://doi.org/10.1093/sysbio/sys029</p>
<p>Saad, S.I. (1961) Pollen morphology in the genus <em>Sonchus</em>. <em>Pollen & Spores</em> 3: 247–260.</p>
<p>Sennikov, A.N. & Illarionova, I.D. (2001) Morphological and anatomical structure of achenes in some species of the genus <em>Sonchus</em> (Asteraceae). <em>Botanicheskii Zhurnal</em> 86 (5): 65–79, Tab. I–II. [in Russian]</p>
<p>Stebbins, G.L. (1953) A new classification of the tribe Cichorieae, family Compositae. <em>Madroño</em> 12: 65–81.</p>
<p>Simmons, M.P. & Ochoterena, H. (2000) Gaps as characters in sequence-based phylogenetic analyses. <em>Systematic Biology</em> 49: 369–381. https://doi.org/10.1093/sysbio/49.2.369</p>
<p>Stamatakis, A. (2006) RAxML-VI-HPC: Maximum Likelihood-Based Phylogenetic Analyses with Thousands of Taxa and Mixed Models. <em>Bioinformatics</em> 22: 2688–2690. https://doi.org/10.1093/bioinformatics/btl446</p>
<p>Stöver, B.C. & Müller, K.F. (2010) TreeGraph 2: Combining and visualizing evidence from different phylogenetic analyses. <em>BMC Evolutionary Biology</em> 11: 7. https://doi.org/10.1186/1471-2105-11-7</p>
<p>Sullivan, J. (1996) Combining data with different distributions of among-site variation. <em>Systematic Biology</em> 45: 375–380. https://doi.org/10.1093/sysbio/45.3.375</p>
<p>Swofford, D.L. (2003) PAUP*: Phylogenetic Analysis Using Parsimony (*and other methods), version 4.0b 10. Sunderland, Massachusetts, Sinauer.</p>
<p>Tamanyan, K. (2014) <em>Sonchus sosnowskyi</em>. <em>The IUCN Red List of Threatened Species</em> 2014: e.T200516A2665823. http://dx.doi.org/10.2305/IUCN.UK.2014-1.RLTS.T200516A2665823.en</p>
<p>Turland, N.J., Wiersema, J.H., Barrie, F.R., Greuter, W., Hawksworth, D., Herendeen, P.S., Knapp, S., Kusber, W.H., Li, D.Z. & Marhold, K. (2018) <em>International code of nomenclature for algae, fungi, and plants (Shenzhen Code) adopted by the Nineteenth International Botanical Congress Shenzhen, China, July 2017</em>. Koeltz Botanical Books, Glashütten. https://doi.org/10.12705/Code.2018</p>
<p>Wang, Z.H., Peng, H. & Kilian, N. (2013) Molecular phylogeny of the <em>Lactuca</em> alliance (Cichorieae subtribe Lactucinae, Asteraceae) with focus on their Chinese centre of diversity detects potential events of reticulation and chloroplast capture. <em>Plos One</em> 8: 1–20. https://doi.org/10.1371/journal.pone.0082692</p>
<p>Zhang, J.W., Boufford, D.E. & Sun, H. (2013) Systematic significance of achene morphology in <em>Soroseris</em>, <em>Syncalathium</em> and <em>Parasyncalathium</em> (Asteraceae: Cichorieae). <em>Botanical Journal of the Linnean Society</em> 173 (3): 476–486. https://doi.org/10.1111/boj.12046</p>
<p>Zhu, S.X., Qin, H.N. & Shih, C. (2006) Achene wall anatomy and surface sculpturing of <em>Lactuca</em> L. and related genera (Compositae: Lactuceae) with notes on their systematic significance. <em>Journal of Integrative Plant Biology</em> 48: 390–399. https://doi.org/10.1111/j.1744-7909.2006.00245.x</p>
<p>Babcock, E.B. (1947) <em>The genus Crepis, Part 1: the taxonomy, phylogeny, distribution and evolution of Crepis</em>. University of California Publications in Botany, Berkeley-Los Angeles, 198 pp.</p>
<p>Barthlott, W. (1981) Epidermal and Seed Surface Characters of Plants: Systematic Applicability and Some Evolutionary Aspects. <em>Nordic Journal of Botany</em> 3: 345–355. https://doi.org/10.1111/j.1756-1051.1981.tb00704.x</p>
<p>Blattner, F.R. (1999) Direct amplification of the entire ITS region from poorly preserved plant material using recombinant PCR. <em>Biotechniques </em>27: 1180–1186. https://doi.org/10.2144/99276st04</p>
<p>Boulos, L. (1960) Cytotaxonomic studies in the genus <em>Sonchus</em> 2. The genus <em>Sonchus</em>, a general treatment. <em>Botaniska Notiser</em> 113: 400–420.</p>
<p>Boulos, L. (1972) Révision systématique du genre <em>Sonchus</em> L. s.l. I. Introduction et classification. <em>Botaniska Notiser</em> 125: 287–305.</p>
<p>Boulos, L. (1973) Révision systématique du genre <em>Sonchus</em> L. s.l. IV. Sousgenre 1. <em>Sonchus</em>. <em>Botaniska Notiser</em> 126: 155–196.</p>
<p>Boulos, L. (1974) Révision systématique du genre <em>Sonchus</em> L. s.l. VI. Sousgenre 3. Origosonchus. Genres Embergeria, Babcockia et Taeckholmia. <em>Botaniska Notiser</em> 127: 402–451.</p>
<p>Bremer, K. (1994) <em>Asteraceae: Cladistics and classification</em>. Timber Press, Portland, Oregon, 752 pp.</p>
<p>Cho, M.-S., Kim, S.-H., Yang, J.Y., Crawford, D.J., Stuessy, T.F., López-Sepúlveda, P. & Kim, S.-C. (2020) Plastid phylogenomics of <em>Dendroseris (Cichorieae; Asteraceae)</em>: insights into structural organization and molecular evolution of an endemic lineage from the Juan Fernández Islands. <em>Frontiers in Plant Science</em> 11: e594272. https://doi.org/10.3389/fpls.2020.594272</p>
<p>Cunningham, C.W. (1997) Can three incongruence tests predict when data should be combined? <em>Molecular Biology and Evolution</em> 14: 733–740. https://doi.org/10.1093/oxfordjournals.molbev.a025813</p>
<p>Diez, M.J. & Meijas, J.A. & Moreno-Socías, E. (1999) Pollen morphology of <em>Sonchus</em> and related genera, and a general discussion. <em>Plant Systematics and Evolution</em> 214: 91–102. https://doi.org/10.1007/BF00985733</p>
<p>Doyle, J.J. & Doyle, J.L. (1987) A rapid DNA Isolation Procedure for Small Quantities of Fresh Leaf Tissue. <em>Phytochemical Bulletin</em> 19: 11–15.</p>
<p>Edgar, R.C. (2004) MUSCLE: Multiple Sequence Alignment with High Accuracy and High Throughput. <em>Nucleic Acids Research</em> 32: 1792–1797. https://doi.org/10.1093/nar/gkh340</p>
<p>Enke, N. & Gemeinholzer, B. (2008) Babcock revisited: new insights into generic delimitation and character evolution in <em>Crepis</em> L. (Compositae: Cichorieae) from ITS and <em>mat</em>K sequence data. <em>Taxon</em> 57: 756–768. https://doi.org/10.1002/tax.573008</p>
<p>Erdtman, G. (1952) <em>Pollen Morphology and Plant Taxonomy</em>. Almqvist and Wiksells, Uppsala, pp. 133–134. https://doi.org/10.1080/11035895209453507</p>
<p>Farris, J.S., Källersjö, M., Kluge, A.G. & Bult, C. (1994) Testing significance of congruence. <em>Cladistics</em> 10: 315–319. https://doi.org/10.1111/j.1096-0031.1994.tb00181.x</p>
<p>Fehrer, J., Gemeinholzer, B., Chrtek, J. & Bräutigam, S. (2007) Incongruent plastid and nuclearDNA phylogenies reveal ancient intergeneric hybridization in <em>Pilosella</em> hawkweeds (<em>Hieracium</em>, Cichorieae, Asteraceae). <em>Molecular Phylogenetics and Evolution</em> 42: 347–361. https://doi.org/10.1016/j.ympev.2006.07.004</p>
<p>Jeffrey, C. (1966) Notes on Compositae: I. The Cichorieae in east tropical Africa. <em>Kew Bulletin</em> 18: 427–486. https://doi.org/10.2307/4115797</p>
<p>Johnson, L. & Soltis, D. (1995) Phylogenetic Inference in Saxifragaceae Sensu Stricto and Gilia (Polemoniaceae) Using matK Sequences. <em>Annals of the Missouri Botanical Garden</em> 82 (2): 149–175. https://doi.org/10.2307/2399875</p>
<p>JSTOR (2000) [continuously updated] Global Plants. Available from: http://plants.jstor.org (accessed 29 June 2021)</p>
<p>Kandemir, A., Makbul, S., Türkme, Z. & Yılmaz, M. (2006) Morphological, Anatomical and Palynological Investigation on <em>Sonchus erzincanicus</em> Matthews (Asteraceae). <em>Turkish Journal of Botany</em> 30: 405–411.</p>
<p>Kavak, S. (2014) <em>Sonchus erzincanicus</em>. The IUCN Red List of Threatened Species e.T19617539A19620981.</p>
<p>Kilian, N. (1997) Revision of <em>Launaea</em> Cass. (Compositae, Lactuceae, Sonchinae). <em>Englera</em> 17: 1–448. https://doi.org/10.2307/3776755</p>
<p>Kilian, N., Gemeinholzer, B. & Lack, H.W. (2009a) Tribe Cichorieae. <em>In</em>: Funk, V.A., Susanna, A., Steussy, T.F. & Bayer, R.J. (Eds.) <em>Systematics, Evolution, and Biogeography of Compositae</em>. IAPT, Vienna, pp. 343–383.</p>
<p>Kilian, N., Hand, R. & Raab-Straube, E von (Eds.) (2009b) [continuously updated] <em>Cichorieae Systematics Portal</em>. Available from: http://cichorieae.etaxonomy.net/portal/ (accessed 29 June 2021)</p>
<p>Kim, S.-C., Crawford, D.J., Francisco-Ortega, J. & Santos-Guerra, A. (1996) A common origin for woody <em>Sonchus</em> and five related genera in the Macaronesian islands: molecular evidence for extensive radiation. <em>Proceedings of the National Academy of Sciences of the United States of America</em> 93: 7743–7748. https://doi.org/10.1073/pnas.93.15.7743</p>
<p>Kim, S.-C., Crawford, D.J. & Jansen, R.K. (1997) Phylogenetic relationships among the genera of the subtribe Sonchinae (Asteraceae): evidence from ITS sequences. <em>Systematic Botany</em> 21: 417–432. https://doi.org/10.2307/2419668</p>
<p>Kim, S.-C., Crawford, D.J., Francisco-Ortega, J. & Santos-Guerra, A. (1999a) Adaptive radiation and genetic differentiation in the woody <em>Sonchus</em> alliance (Asteraceae: Sonchinae) in the Canary Islands. <em>Plant Systematics and Evolution</em> 215: 101–118. https://doi.org/10.1007/BF00984650</p>
<p>Kim, S.-C., Crawford, D.J., Jansen, R.K. & Santos-Guerra, A. (1999b) The use of a non-coding region of chloroplast DNA in phylogenetic studies of the subtribe Sonchinae (Asteraceae: Lactuceae). <em>Plant Systematics and Evolution</em> 215: 85–99. https://doi.org/10.1007/BF00984649</p>
<p>Kim, S.-C., Lu, C.T. & Lepschi, B.J. (2004) Phylogenetic positions of Actites megalocarpa and Sonchus hydrophilus (Sonchinae: Asteraceae) based on ITS and chloroplast non-coding DNA sequences. <em>Australian Systematic Botany</em> 17: 73–81. https://doi.org/10.1071/SB03019</p>
<p>Kim, S.-C., Lee, C. & Mejías, J.A (2007) Phylogenetic analysis of chloroplast DNA matK gene and ITS of nrDNA sequences reveals polyphyly of the genus <em>Sonchus</em> and new relationships among the subtribe Sonchinae (Asteraceae: Cichorieae). <em>Molecular Phylogenetics and Evolution</em> 44: 578–597. https://doi.org/10.1016/j.ympev.2007.03.014</p>
<p>Kim, S.-C., Mejías, J.A. & Pesach, L. (2008) Molecular confirmation of the hybrid origin of the critically endangered western Mediterranean endemic <em>Sonchus pustulatus </em>(Asteraceae: Sonchinae). <em>Journal of Plant Research</em> 121: 357–364. https://doi.org/10.1007/s10265-008-0166-8</p>
<p>Kirpicznikov, M.E. (1964a) <em>Sonchus</em> L. <em>In</em>: Bobrov, E.G. & Tzevlev, N.N. (Eds.) <em>Flora of the USSR</em>, vol. 29, Akademiya Nauk SSSR, Moscow, Leningrad, pp. 243–259.</p>
<p>Kirpicznikov, M.E. (1964b) The system of <em>Sonchus</em> as accepted in the Flora of the USSR. <em>Novosti Sistematiki Vysshikh Rastenii</em> 1: 341–342.</p>
<p>Lee, C., Kim, S.-C., Lundy, K. & Santos-Guerra, A. (2005) Chloroplast DNA phylogeny of the woody <em>Sonchus </em>alliance (Asteraceae: Sonchinae) in the Macaronesian Islands. <em>American Journal of Botany</em> 92: 2072–2085. https ://doi.org/10.3732/ajb.92.12.2072</p>
<p>Matthews, V.A. (1974) <em>Sonchus erzincanicus</em> V. A. Matthews. <em>Notes from the Royal Botanic Garden, Edinburgh</em> 33: 429.</p>
<p>Matthews, V.A. (1975) <em>Sonchus</em> L. <em>In</em>: Davis, P.H. (Ed.) <em>Flora of Turkey and the East Aegean Islands</em>, vol. 5. Edinburgh Univ. Press, Edinburgh, pp. 690–693.</p>
<p>Mejías, J.A. (1992) Reproductive biology in the Iberian taxa of the genera <em>Sonchus</em> and <em>Aetheorhiza</em> (Asteraceae: Lactuceae). <em>Flora Mediterranea</em> 2: 15–32.</p>
<p>Mejías, J.A. (2017) <em>Sonchus</em> L. <em>In</em>: Talavera, S., Buira, A., Quintanar, A., García, M.Á., Talavera, M., Fernández Piedra, P. & Aedo, C. (Eds.) <em>Flora Iberica XVI (II), Compositae (partim)</em>. Real Jardín Botánico, CSIC, Madrid, pp. 871–891.</p>
<p>Mejías, J.A. & Kim, S.-C. (2012) Taxonomic treatment of Cichorieae (Asteraceae) endemic to the Juan Fernandez and Desventuradas Islands (SE Pacific). <em>Annales Botanici Fennici</em> 49 (3): 171–178. https://doi.org/10.5735/085.049.0303</p>
<p>Mejías, J.A. & Valdes, B. (1987) Karyological studies in <em>Sonchus</em> section <em>Maritimi</em> (Asteraceae) from the Iberian Peninsula. <em>Botanical Journal of the Linnean Society</em> 98: 61–69.</p>
<p>Mejías, J.A., Chambouleyron, M., Kim, S.H., Infante, M.D., Kim, S.-C. & Léger, J.F. (2018) Phylogenetic and morphological analysis of a new cliff-dwelling species reveals a remnant ancestral diversity and evolutionary parallelism in <em>Sonchus</em> (Asteraceae). <em>Plant Systematics and Evolution</em> 304: 1023–1040. https://doi.org/10.1007/s00606-018-1523-2</p>
<p>Miller, M.A., Pfeiffer, W. & Schwartz, T. (2010) <em>Creating the CIPRES Science Gateway for inference of large phylogenetic trees</em>.<em> In: Proceedings of the Gateway Computing Environments Workshop (GCE), New Orleans, Louisiana, 14 Nov 2010.</em> pp. 45–52. [Piscataway: IEEE] https://doi.org/10.1109/GCE.2010.5676129</p>
<p>Müller, K. (2004) PRAP-Computation of Bremer Support for Large Data Sets. <em>Molecular Phylogenetics and Evolution</em> 31: 780–782. https://doi.org/10.1016/j.ympev.2003.12.006</p>
<p>Müller, K. (2005a) SeqState: Primer design and sequence statistics for phylogenetic DNA datasets. <em>Applied Bioinformatics</em> 4 (1): 65–69. https://doi.org/10.2165/00822942-200504010-00008</p>
<p>Müller, K. (2005b) The efficiency of different search strategies in estimating parsimony jackknife, bootstrap, and Bremer support. <em>BMC Evolutionary Biology</em> 5: 58.</p>
<p>Müller, K., Müller, J. & Quandt, D. (2010) PhyDE: Phylogenetic Data Editor, version 0.9971. Available from: http://www.phyde.de/index.html (accessed 20 January 2022)</p>
<p>Nazarova, E.A. & Barsegyan, A.M. (1983) <em>Sonchus araraticus</em> (Asteraceeae) – A New Species From Armenia. <em>Botanicheskii Zhurnal</em> 68: 950–952.</p>
<p>Nixon, K.C. (1999) The parsimony ratchet, a new method for rapid parsimony analysis. <em>Cladistics</em> 15: 407–414. https://doi.org/10.1111/j.1096-0031.1999.tb00277.x</p>
<p>Nylander, J.A.A. (2004) MrModeltest, version 2. Evolutionary Biology Centre, Uppsala University. [https://www.abc.se/~nylander/mrmodeltest2/mrmodeltest2.html]</p>
<p>Punt, W., Hoen, P.P., Blackmore, S., Nilsson, S. & Thomas, L.A. (2007) Glossary of pollen and spore terminology. <em>Review of Palaeobotany and Palynology</em> 143: 1–81. https://doi.org/10.1016/j.revpalbo.2006.06.008</p>
<p>Ronquist, F., Teslenko, M., Mark, P.V.D., Ayres, D.L., Darling, A., Hohna, S., Larget, B., Liu, L., Suchard, M.A. & Huelsenbeck, J.P. (2012) MrBayes 3.2: efficient Bayesian phylogenetic inference and model choice across a large model space. <em>Systematic Biology</em> 61: 539–542. https://doi.org/10.1093/sysbio/sys029</p>
<p>Saad, S.I. (1961) Pollen morphology in the genus <em>Sonchus</em>. <em>Pollen & Spores</em> 3: 247–260.</p>
<p>Sennikov, A.N. & Illarionova, I.D. (2001) Morphological and anatomical structure of achenes in some species of the genus <em>Sonchus</em> (Asteraceae). <em>Botanicheskii Zhurnal</em> 86 (5): 65–79, Tab. I–II. [in Russian]</p>
<p>Stebbins, G.L. (1953) A new classification of the tribe Cichorieae, family Compositae. <em>Madroño</em> 12: 65–81.</p>
<p>Simmons, M.P. & Ochoterena, H. (2000) Gaps as characters in sequence-based phylogenetic analyses. <em>Systematic Biology</em> 49: 369–381. https://doi.org/10.1093/sysbio/49.2.369</p>
<p>Stamatakis, A. (2006) RAxML-VI-HPC: Maximum Likelihood-Based Phylogenetic Analyses with Thousands of Taxa and Mixed Models. <em>Bioinformatics</em> 22: 2688–2690. https://doi.org/10.1093/bioinformatics/btl446</p>
<p>Stöver, B.C. & Müller, K.F. (2010) TreeGraph 2: Combining and visualizing evidence from different phylogenetic analyses. <em>BMC Evolutionary Biology</em> 11: 7. https://doi.org/10.1186/1471-2105-11-7</p>
<p>Sullivan, J. (1996) Combining data with different distributions of among-site variation. <em>Systematic Biology</em> 45: 375–380. https://doi.org/10.1093/sysbio/45.3.375</p>
<p>Swofford, D.L. (2003) PAUP*: Phylogenetic Analysis Using Parsimony (*and other methods), version 4.0b 10. Sunderland, Massachusetts, Sinauer.</p>
<p>Tamanyan, K. (2014) <em>Sonchus sosnowskyi</em>. <em>The IUCN Red List of Threatened Species</em> 2014: e.T200516A2665823. http://dx.doi.org/10.2305/IUCN.UK.2014-1.RLTS.T200516A2665823.en</p>
<p>Turland, N.J., Wiersema, J.H., Barrie, F.R., Greuter, W., Hawksworth, D., Herendeen, P.S., Knapp, S., Kusber, W.H., Li, D.Z. & Marhold, K. (2018) <em>International code of nomenclature for algae, fungi, and plants (Shenzhen Code) adopted by the Nineteenth International Botanical Congress Shenzhen, China, July 2017</em>. Koeltz Botanical Books, Glashütten. https://doi.org/10.12705/Code.2018</p>
<p>Wang, Z.H., Peng, H. & Kilian, N. (2013) Molecular phylogeny of the <em>Lactuca</em> alliance (Cichorieae subtribe Lactucinae, Asteraceae) with focus on their Chinese centre of diversity detects potential events of reticulation and chloroplast capture. <em>Plos One</em> 8: 1–20. https://doi.org/10.1371/journal.pone.0082692</p>
<p>Zhang, J.W., Boufford, D.E. & Sun, H. (2013) Systematic significance of achene morphology in <em>Soroseris</em>, <em>Syncalathium</em> and <em>Parasyncalathium</em> (Asteraceae: Cichorieae). <em>Botanical Journal of the Linnean Society</em> 173 (3): 476–486. https://doi.org/10.1111/boj.12046</p>
<p>Zhu, S.X., Qin, H.N. & Shih, C. (2006) Achene wall anatomy and surface sculpturing of <em>Lactuca</em> L. and related genera (Compositae: Lactuceae) with notes on their systematic significance. <em>Journal of Integrative Plant Biology</em> 48: 390–399. https://doi.org/10.1111/j.1744-7909.2006.00245.x</p>