Transfer of Dodecatheon to Primula (Primulaceae) Author(S) :Austin R
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Transfer of Dodecatheon to Primula (Primulaceae) Author(s) :Austin R. Mast and James L. Reveal Source: Brittonia, 59(1):79-82. 2007. Published By: The New York Botanical Garden DOI: 10.1663/0007-196X(2007)59[79:TODTPP]2.0.CO;2 URL: http://www.bioone.org/doi/full/10.1663/0007-196X %282007%2959%5B79%3ATODTPP%5D2.0.CO%3B2 BioOne (www.bioone.org) is a a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/ terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Transfer of Dodecatheon to Primula (Primulaceae) Austin R. Mast1 and James L. Reveal2 1 Department of Biological Sciences, Florida State University, Tallahassee, FL 32306, U.S.A.; e-mail: [email protected] 2 University of Maryland, College Park, Maryland 20742-5815, U.S.A. and The New York Botani- cal Garden, Bronx, New York 10458-5126, U.S.A.; mailing address: 18625 Spring Canyon Road, Montrose, Colorado 81401-7906, U.S.A.; e-mail: [email protected] Abstract. Phylogenies inferred from both chloroplast and nuclear DNA regions have placed the small genus Dodecatheon (the shooting stars; 17 spp.) among the descen- dants of the most recent common ancestor of Primula (the primroses; ca. 430 spp.). This is congruent with conclusions previously derived from morphology and cytol- ogy. We illustrate how failure to formalize this information in the circumscription of Primula might have impeded understanding of the evolution of distyly (as seen in Primula) and buzz-pollination (as seen in Dodecatheon). To avoid future confusion, we make new combinations for Dodecatheon in Primula, and erect Primula sect. Dodecatheon in Primula subgenus Auriculastrum for the taxa from Dodecatheon. Key words: Buzz-pollination, distyly, Dodecatheon, heterostyly, Primula, Primu- laceae. Recent molecular evidence from both the et al. (2003) represents the most complete chloroplast (cpDNA; Källersjö et al., 2000; sampling of nuclear DNA (in this case, the Mast et al., 2001, 2004, 2006; Trift et al., two internal transcribed spacers of the nu- 2002) and nuclear (Martins et al., 2003) clear ribosomal DNA) and subgenera of genomes is congruent with prior hypotheses Primula (five of seven) to date. In the nuclear based on morphological and cytological evi- DNA phylogeny inferred in that study, the dence (Thompson, 1953; Wendelbo, 1961; single sampled species of Dodecatheon is Richards, 1993; Holmgren, 1994) that Dode- sister to the single sampled species of P. sub- catheon L. (17 spp.) is most closely related to gen. Auriculastrum (100% bootstrap fre- one of the seven subgenera of Primula L. (ca. quency). Thus, DNA sampling of two in- 430 spp.; Primulaceae). The study by Mast et dependent ‘linkage partitions’ (sensu al. (2004) represents the most extensive sam- Slowinski & Page, 1999) is congruent in sup- pling of cpDNA characters (seven regions) port of the conclusion that Primula is para- and taxa within Dodecatheon (16 of the 17 phyletic with respect to Dodecatheon. spp. recognized here) and the closely related While the buzz-pollinated flowers of Do- Primula subgen. Auriculastrum Schott (all decatheon distinguish the lineage from others four sections sampled, three of them exhaus- in Primula, individuals of Dodecatheon in tively) to date. In the cpDNA phylogeny in- sterile, pre-anthetic, and fruiting stages are ferred in that study, sampled members of Do- strikingly similar to members of P. subgen. decatheon form a monophyletic group (97% Auriculastrum. Both groups have members bootstrap frequency) that is sister to the only that grow in moist alpine meadows and along species of Primula sect. Suffrutescens A. J. streamsides, have chromosome numbers of Richards (100% bootstrap frequency) of P. 2n = 44, and produce valvate capsules on long subgen. Auriculastrum. The study by Martins scapes arising from a rosette of fleshy, lance- Brittonia, 59(1), 2007, pp. 79–82. ISSUED: 30 March 2007 © 2007, by The New York Botanical Garden Press, Bronx, NY 10458-5126 U.S.A. 80 brittonia [VOL. 59 shaped leaves with involute vernation ula grandis Trautv. by Richards [2002]), are (Thompson, 1953). Furthermore, Thompson monomorphic. That is, they have a single flo- (p. 75) noted that D. jeffreyi Van Houtte and ral morphology within each species. Most P. parryi A. Gray (a member of P. subgen. monomorphic lineages in Primula are Auriculastrum) are “virtually indistinguish- thought to arise by a recombination of the able when the corollas and inserted anthers “heterostyly supergene” that is later fixed in a are removed.” Both Dodecatheon and P. sub- population and produces flowers in which the gen. Auriculastrum occur in western North anthers and stigma are both high in the America, though each is also found else- corolla tube and pollen is large (see Mast et where (one sp. of Dodecatheon extends al. [2006] for a recent review). However, across the Bering Strait; P. subgen. Auricu- flowers of Dodecatheon, Cortusa, and lastrum is also found in Pacific coastal Asia Sredinskya have their stigmas positioned well and in Europe). Some previous authors (e.g., above their anthers (by virtue of long styles Pax, 1889) grouped Dodecatheon at the tribal and filaments adnate low in the corolla tube), rank (as Cyclameae Dumort.) with another differing in the phenotype expected after the buzz-pollinated genus, the Mediterranean typical recombinational route to monomor- genus Cyclamen L., which was still then con- phy. Mast et al. (2004) marshaled evidence to sidered part of the family (c.f., Källersjö et suggest that Dodecatheon, and perhaps Cor- al., 2000). However, recent authors (Thomp- tusa and Sredinskya as well, represent an al- son, 1953; Wendelbo, 1961; Richards, 1993, ternate route to monomorphy in the descen- 2002; Holmgren, 1994) have taken the geo- dents of the MRCA of Primula: the fixation graphical, morphological, and cytological of the recessive alleles of the heterostyly su- similarities as evidence for a close phyloge- pergene and thus the “pin” morphology. netic relationship between Dodecatheon and The alternate route to monomorphy pro- Primula, and interpreted floral similarities posed by Mast et al. (2004) for descendants between Dodecatheon and Cyclamen as due of the MRCA of Primula was not previously to convergence on buzz-pollination. suggested, in part, because comparative biol- Dodecatheon is one of four genera com- ogists thinking about the function, genetics, posed of species that have been segregated and evolution of distyly confined their atten- from Primula but that are inferred to be de- tion to monomorphic species in genera that scended from the most recent common an- also contained distylous members. Thus, they cestor (MRCA) of Primula using morpholog- were not making potentially informative ical and cytological (Wendelbo, 1961), morphological comparisons involving Dode- cpDNA (Källersjö et al., 2000; Mast et al., catheon (e.g., pollen size between Dode- 2001, 2004, 2006; Trift et al., 2002), and nu- catheon and P. subgen. Auriculastrum; Mast clear DNA (Martins et al., 2003) evidence. et al., 2004). By making these comparisons, Like 92% of species in Primula, one of the Mast et al. (2004) placed the floral variation four segregated genera, Dionysia Fenzl (ca. seen between these groups into an evolution- 50 spp. of mostly cushion plants from the ary scenario that involves the co-opting of Middle East; Grey-Wilson, 1989; Trift et al., pre-existing features from the distylous an- 2004), is distylous. In distylous plants, a ge- cestor (e.g., the “pin” positioning of stigma netic polymorphism produces two floral and anthers), the genesis of new features with types: the “pin” morph has stigmas high and the origin of Dodecatheon (e.g., the enlarge- anthers low in the corolla tube and small ment of the anthers and delayed longitudinal pollen; the “thrum” morph has stigmas low dehiscence to produce “poricidal” anthers in and anthers high in the corolla tube and large the first days of anthesis), and the later fine- pollen (Darwin, 1877; Ganders, 1979; Bar- tuning of the buzz pollination syndrome (de- rett, 1992, 2002; Richards, 2002). Like the velopment of rugosity on the anther connec- remaining 8% of species in Primula, the tives). The study of Mast et al. (2004) clearly three other segregated genera, Dodecatheon, illustrates both the utility of recognizing phy- Cortusa L. (1[–3] spp. from Asia), and logenetic relationships in comparative biol- Sredinskya (Stein) Fedorov (1 sp. from the ogy, and the importance of maintaining Caucasus; most recently recognized as Prim- monophyly in our currently recognized taxa. 2007] mast & reveal: transfer of dodecatheon (primulaceae) 81 In this paper, we make new combinations redolens H. M. Hall, Bot. Gaz. 31: 392. for the currently accepted entities of Dode- 1901, non P. redolens Balf. f. & Kingdon- catheon in Primula, and establish Primula Ward, 1916. Replaces D. redolens (H. M. sect. Dodecatheon (L.) A. R. Mast & Reveal Hall) H. J. Thomps., Contr. Dudley Herb. as a member of P. subgen. Auriculastrum. 4: 143. 1953. This is a necessary step in making Primula Primula frenchii (Vasey) A. R. Mast & Re- monophyletic and produces a monophyletic veal, comb. nov., Dodecatheon meadia P. subgen. Auriculastrum. Although both var. frenchii Vasey, Gray’s Manual, ed. 6. Primula and Dodecatheon were proposed by 735b. 1891. Linnaeus in 1753, we choose to retain Prim- Primula frigida (Cham.