Jepson Flora Project: Jepson Interchange for California Floristics    
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Spirodela punctata (G. Mey.) C. H. Thomps.
ARACEAE (genus previously included in Lemnaceae)
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Information from the Index of California Plant Names (ICPN)
Synonyms Cited in The Jepson Manual Spirodela oligorrhiza (Kurz) Hegelm.
Initial Editorial Analysis 23 Jul 2002; 20 Jan 2004
Notes on Authorship of Name both = Authors of Plant Names
Source of Report for California The Jepson Manual [Ed. 1]
Correspondence and Comments Subsequent to Initial Analysis
Correspondence 1 Preston e-mail of 5 Jul 2000, "Spirodela punctata G. Meyer = Landoltia punctata (G. Meyer) D.H. Les & D.J. Crawford; Les, D. H., and D. J. Crawford. 1999. Landoltia (Lemnaceae), a new genus of duckweed. Novon 9 see Comment 1
Editorial Comments 1 Correspondence 1 indicates treatment as Landoltia punctata (G. Meyer) D.H. Les & D.J. Crawford since The Jepson Manual [Ed. 1]. [Segregated from Spirodela to Landoltia by Les & D. J. Crawford since The Jepson Manual [Ed. 1] (Novon 9(4): 532. 1999), based on evidence from morphology, allozymes, and cpDNA (rbcL) sequences.]
Correspondence 2 25 Oct 2003 e-mail from Wayne P. Armstrong, The Jepson Manual [Ed. 1] author of Lemnaceae see Comment 2
Editorial Comments 2 Correspondence 1 indicates that, according to Wayne P. Armstrong, The Jepson Manual [Ed. 1] author of Lemnaceae, Landoltia represents an isolated clade distinct from both Lemna and Spirodela, based on evidence from morphology, anatomy, flavonoids, allozymes, and DNA sequences from chloroplast genes (rbcL, matK) and introns (trnK, rpl16) (Les, D. H. and D. J. Crawford. 1999. Landoltia (Lemnaceae), A New Genus of Duckweeds. Novon 9: 530-533. Les, et al. 2002. Phylogeny and Systematics of Lemnaceae, the Duckweed Family. Systematic Botany 27: 221-240), so that the correct name for Spirodela punctata (G. Meyer) C. Thompson is Landoltia punctata (G. Meyer) Les & Crawford. Armstrong also indicates that the changes are summarized at his websites http://waynesword.palomar.edu/1wayindx.htm#clad (cladogram), and http://waynesword.palomar.edu/1wayindx.htm#key (revised key).
Correspondence 3 20 Oct 2011 e-mail from Dave Keil see Comment 3
Editorial Comments 3 Correspondence 3 indicates that Ward (2011. J. Bot. Res. Inst. Texas 5(1):197-203) presented a strong case for treating Landoltia punctata as Spirodela oligorhiza (Kurz) Hegelm., neotypified Spirodela punctata as excluding the plants treated as Landoltia punctata in The Jepson Manual [Ed. 2], and downplayed the distinctiveness of Landoltia as a genus, arguing that it should not be separated from Spirodela; according to Keil, evidently a correct combination in Landoltia has not been made for this taxon, if one wishes to recognize that genus.
Correspondence 4 22 Jul 2012 e-mail from Wayne P. Armstrong, The Jepson Manual [Ed. 2] Author of Landoltia and Spirodela see Comment 4
Editorial Comments 4 Correspondence 4 includes reasons for Armstrong's rejection of Ward's position, and his recommendation that no changes to Jepson Flora Project be made in connection with it: [paragraph] "Dear Tom: [paragraph] Here is a shortened version of my objection to adopting Ward's (2011) nomenclatural changes. I can shorten it more if necessary. [paragraph] I recommend that the proposed change from Landoltia punctata to Spirodela oligorrhiza by Daniel B. Ward be rejected and that the existing binomial in the Jepson Manual (2nd Ed) Landoltia punctata (G. Mey.) Les & D.J. Crawford be retained in its present form. I have summarized my reasoning in more detail at the following URL, including input from Dr. Elias Landolt, the leading authority on the duckweed subfamily Lemnoideae: [paragraph] http://waynesword.palomar.edu/1wayindx.htm#Landoltia [paragraph] Ward uses the term "Lesser Greater Duckweed" ("LG Duckweed") to refer to the plant that we call Landoltia punctata. The original 1818 type specimen of "LG Duckweed" (Lemna punctata Meyer) was lost. Ward speculates that Meyer's original specimen from the Essequibo River, Guyana was not "LG Duckweed." Therefore, he neotypified Lemna punctata using a different species (Spirodela intermedia) collected from Surinam in 1951. How can we be certain beyond any shadow of a doubt that Meyer's original collection was not "LG Duckweed." Elias Landolt, who has examined specimens from these regions, concurs with my conclusions. Adopting Ward's 2011 neotypification will make Landoltia no longer available for the intended species it was named for. Landoltia punctata will [would] now be a synonym for the South American species known as Spirodela intermedia W. Koch. As Landolt explained to me in a message 4 July 2012, why cause "such terrible chaos in Spirodela nomenclature" by neotypifying Meyer's type specimen with a different species that he speculates might have occurred in the original type locality. [paragraph] The monotypic genus Landoltia is warranted based upon a comprehensive analysis of the Lemnaceae by Les et al. (2002). More than 4,700 characters were studied, including data from morphology and anatomy, flavonoids, allozymes, and DNA sequences from chloroplast genes (rbcL, matK) and introns (trnK, rpl16). The genus Landoltia is well substantiated in the article and phylogenetic cladograms by Les et al. (2002). This is consistent with the monophyletic objectives of the Jepson Manual (2nd. Ed.). Please refer to the above website for a more detailed explanation. [paragraph] Sincerely, [paragraph] Wayne P. Armstrong [paragraph] 22 July 2012." [Therefore, nomenclature as indicated in this Index retained, 18 Jan 2013.]
Correspondence 5 10 Jul 2014 e-mail from Wayne P. Armstrong, The Jepson Manual [Ed. 2] Author of Landoltia and Spirodela see Comment 5
Editorial Comments 5 Correspondence 5 includes reference to a recently published paper by John Wiersema (Plant Biology ISSN 1435-8603; doi:10.1111/plb.12209) in which he presents nomenclatural arguments against accepting the attempt by Ward (Correspondence 3) to re-neotypify Landoltia punctata, noting that if accepted it would disrupt the names of two duckweed species as well as that of Landoltia, and supports continued usage of names as supported by Armstrong in Correspondence 4. [Therefore, nomenclature as indicated in this Index again retained, 16 Jul 2014.]
Editorial Summary and Current Status
Editorial Summary rejection, new combination, different genus, since The Jepson Manual [Ed. 1]
Current Status JFP-1a, taxonomic or nomenclatural synonym for taxon native to CA
Current Name Landoltia punctata
Current Status Authority Wayne P. Armstrong, as Author, The Jepson Manual [Ed. 1]
Current Status Date 23 Jul 2002; 20 Jan 2004
List of names for this Current Status category
List of ICPN names in Spirodela
List of names from ICPN, Hrusa's Crosswalk, and Jepson Flora in Spirodela
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