Evidence for a Close Relationship Between Iostephane and Viguiera (Asteraceae: Heliantheae) Author(s): Edward E. Schilling and Jose L. Panero Source: American Journal of Botany, Vol. 78, No. 8 (Aug., 1991), pp. 1054-1062 Published by: Botanical Society of America Stable URL: http://www.jstor.org/stable/2444894 Accessed: 09/11/2009 13:53 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/action/showPublisher?publisherCode=botsam. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Botanical Society of America is collaborating with JSTOR to digitize, preserve and extend access to American Journal of Botany. http://www.jstor.org AmericanJournal of Botany 78(8): 1054-1062. 1991. EVIDENCE FOR A CLOSE RELATIONSHIP BETWEEN IOSTEPHANE AND VIGUIERA (ASTERACEAE: HELIANTHEAE)1 EDWARD E. SCHILLING2 AND JOSE L. PANERO Departmentof Botany, University of Tennessee, Knoxville, Tennessee 37996-1100; and Grinnell College, Grinnell,Iowa 50112-0806 The phylogeneticrelationship of Iostephaneisassessed using data from morphology, flavonoid chemistry, and chloroplastDNA and nuclear ribosomal DNA restrictionfragment analysis. Morphologicalevidence supportsplacement of Iostephanein subtribeHelianthinae, but fails to clarifythe placementof the genuswithin this assemblage.Further evidence for the placement of Iostephanein subtribeHelianthinae is provided by the presencein all species of the genus of floralflavonoids of the chalcone/auronetype, whichprovides a distinctivetrait for the subtribe within the tribe Heliantheae.Analysis of chloroplastDNA from two species of Iostephane,L heterophyllaand I. madrensis,in comparisonto Viguieraand relatedgenera indicates that the restrictionsite patternswith 16 enzymes for the Iostephanespecies are virtually identical to one another as well as to those of Viguierasect. Maculatae. Data from restrictionfragment patternsof nuclearrDNA are concordantwith the resultsfrom chloroplastDNA in suggesting a direct relationship between the two groups. The close phylogenetic relationship between Iostephaneand Viguierasect. Maculatae suggestedby the DNA restrictionfragment data was not suggestedby any other set of data. IostephaneBenth. is a small genus of about Viguieraand its related genera, including He- four species endemic to Mexico. The genus lianthusL., HeliomerisNutt., PappobolusS. F. forms a readily recognizableassemblage based Blake, Simsia Pers., and Tithonia Desf. ex on its subscapiform, heavy-rooted perennial Gmelin. In addition to morphological char- herbhabit and preferencefor pine, oak, or pine- acters, Viguieraand related genera have been oak forests between 1,500 and 3,000 m (Stro- shown to be characterizedby the shared pres- ther, 1983). Because there is variability be- ence of floral chalcone/auronepigments (Har- tween species for the presence or absence of a borne and Smith, 1978; Schilling, 1983; Rie- pappus, a characteroften consideredto be im- seberg and Schilling, 1985; Schilling and portant at the generic level in Asteraceae, the Panero, 1988; Schilling, Panero, and Bohm, genus has only recently been circumscribedin 1988; Schilling and Spooner, 1988), a type of its current constitution (Strother, 1983). The flavonoid that is otherwiseuncommon in tribe relationshipsof the genus have been suggested Heliantheae except in subtribe Coreopsidinae to lie with subtribe Helianthinae (Robinson, (Crawfordand Stuessy, 1981). Data from chlo- 1981; Strother, 1983) based on reproductive roplast DNA (cpDNA) restriction fragment characters,including the presenceof pales, her- variation provides furtherevidence for the re- maphroditic disk flowers, striate and carbon- latedness of this group, and suggests that Vi- ized achenes, sterile rays, a single stigmatic guiera as currentlyconstituted forms a para- surface,and style ducts outside the veins in the phyleticassemblage relative to the othergenera shaft (Robinson, 1981). (Schilling and Jansen, 1989). Robinson (1981) suggests that the subtribe The currentstudy is an attemptto determine Helianthinaeis one of the most concisely char- the phylogenetic relationships of Iostephane. acterized subtribes of the tribe Heliantheae. Initially, a single sample of the genus was an- The bulk of subtribe Helianthinae is formed alyzed as a possible outgroupto polarize chlo- by a group of species currently classified as roplast DNA restriction site changes within Viguieraand related genera. Additional sam- ' Received for publication 24 October 1990; revision ples were then analyzedto verify the somewhat accepted22 March 1991. surprisingresult that its chloroplast DNA re- The authorsthank John Strother,Robert K. Jansen,and striction site pattern is very similar to that of Mary Lou Schmid for assistance with various phases of Viguierasect. Maculatae (S. F. Blake) Panero the project;the StrybingArboretum for providinga sample & E. Schilling,a groupthat is pheneticallyvery of Iostephaneheterophylla; and Loren H. Rieseberg for rDNA restriction site map data from Helianthus. This different. Additional data from morphology, work was supportedby NSF grantBSR 88-06513 to EES. chemistry,and restrictionfragment analysis of 2Author for correspondence. a second molecule, nuclear ribosomal DNA 1054 August 1991] SCHILLING AND PANERO-IOSTEPHANE/VIGUIERA RELATIONSHIP 1055 (rDNA), were then sought to provide further TABLE 1. Charactersscored for cladisticanalysis of Vi- perspective on these results. guiera, lostephane, Helianthus,Tithonia and Simsia 1. Habit (Oa = woody; 1 = herbaceous) MATERIALSAND METHODS 2. Habit (Oa = not scapose; 1 = scapose) 3. Chromosome number (Oa = 18; 1 = 17; 9 = 8) The following samples of Iostephane were 4. Leaves lobed (Oa = absent; 1 = present) analyzed for DNA restriction site variation, 5. Leaf vein course (0 = straight/sinuous;1 = zigzag) using living plants grown at the University of 6. Leaf vein areolation (0 = well developed; 1 = im- Tennessee greenhouses (all originating from perfect) 7. Synflorescencestructure (0 = dichasial; 1 = mono- Mexico; vouchers at TENN): L heterophylla: chasial) Durango, Panero and Schilling 1549 (I1); 8. Head shape(0 = hemispherical;1 = campanulate/cy- Breedlove44199 (12;grown from seed provid- lindrical) ed by Strybing Arboretum);Guerrero, Schil- 9. Phyllaryshape (Oa = narrowedgradually; 1 = narrowed ling and Panero 86-A (13); Jalisco, Schilling abruptly) and Panero 88-53 (14);and L madrensis:Gua- 10. Pale apex shape (0 = entire; 1 = trifid) najuato, Schilling and Panero 88-22 (IM). 11. Ray corollaUV nectarguides (0 = absent;1 = present) 12. Disk corolla shape (Oa = straight;1 = bulbous at base Analysis of morphology and floral flavonoids of throat) utilized these samples, as well as the following, 13. Disk corolla lobe color (Oa = yellow; 1 = black) using material collected from natural popula- 14. Disk corolla lobe sclerified cells (0 = absent; 1 = tions: L papposa, Oaxaca, Panero et al. 617; present) L trilobata,Oaxaca, Schilling and Panero 88- 15. Disk corolla elongate moniliform glands (0 = rare; I = present) 34. 16. Disk corolla tube glands (0 = present; 1 = absent) For morphological studies, the 33 samples 17. Stamenconnective pubescence (0 = none; 1 = present) of Viguiera,Helianthus, Heliomeris, Simsia, 18. Crystalsin staminalfilaments (0 = few; 1 = abundant) and Tithonia (species names in Fig. 1; sources 19. Anther color (0 = black; 1 = orange) in Table 1 of Schilling and Jansen, 1989) an- 20. Anthercollar cells (0 = thickened; 1 = heavily thick- alyzed previously for cpDNA variation were ened) 21. Antherendothecial cells (0 = polarized;1 = partially consideredto be exemplarsof their respective polarized) taxa, and were analyzedtogether with samples 22. Style appendage(0 = minute; 1 = well developed) of Iostephanespecies. A total of 27 characters 23. Style branchshape (0 = deltoid; 1 = tapering) (Table 1) was scored for these samples, in- 24. Ray ovary (0 = short; 1 = long, narrow) cluding ones used traditionallyfor taxonomic 25. Disk achene pappus (0 = persistent; 1 = deciduous; delimitation as well as novel charactersfrom 9 = absent) leaf venation and floralmicromorphology (the 26. Disk achene pappus (0 = present; 1 = absent) 27. Disk (Oa = I = latter discussed fully in Panero, in press). De- achene type biconvex; very flattened) letion of sampleswith identical scoresfor these a Plesiomorphic character state, polarized relative to charactersresulted in a data set of 25 samples Flourensia. used for cladistic analysis (deleted samples in- cluded Helianthus giganteus, two samples of nol: acetic acid: water (3:1:1) and 15%acetic Viguieradentata, V. deltoidea, V. incana, V. acid.