American Azaleas, Part II Misinformation, Unanswered Questions, and Future Research Needs By Charlie Andrews—Cumming,

Editor's Note: This is Part II based from the keynote presentation So; given at the ASA Convention in Little Rock, AR, April 7, 2018. Part I is in the Summer 2018 issue of The Azalean, p. 40-45. t,:• Ni... - -e? '-'4,,e* , • - .1h '-'4* Re Misinformation Much misinformation on our native azaleas exists in the literature and has since the beginning. Let me give just a few examples:

The Name Azalea a) Linnaeus first coined the term Azalea as a new species back in 1735 because he thought his new species required a a ) dry, arid habitat.1 )

O Azalea from new Latin from ancient Greek (azaleos, 0 dry) because it grows in dry soil. C Wiktionary, 3/22/2018 • Photo 1—This is the typical of what Frederick Pursh called the -colored blossoms of R. arborescens. Linnaeus found these high in the treeless Lapland The can occasionally have a yellow throat or blotch, and be flushed with some pink, usually as buds are opening. Alps in what he said were sandy, rocky, dry places. Since half Pink and light yellow blossoms are found on rare occasions of the ground was still covered in snow in July with water and may be a sign of hybridization. running in rivulets through the snow, how he determined it was arid is unclear.2 With his limited exposure to azaleas, V Map 1—Note the supposed but doubtful distribution Linnaeus did not realize that almost every azalea prefers of R. canescens in . This southeastern constantly moist, not wet soil. species is sometimes called the mountain azalea possibly because it has been confused with the more Rose Colored arborescens northern and higher elevation R. prinophyllum. Frederick Pursh introduced R. arborescens, perhaps our best white deciduous azalea, as a new species in 1814 and stated he had seen it in the wild and in Bartram's garden outside Philadelphia. He described the species as having rose-colored flowers.3 [See Photo 1] This flower color description was repeated by other botanical authors for almost 100 years, including the well- respected John Torrey, Asa Gray, John Claudius Loudon, and Alphonso Wood. Do you think these authors had actually seen a living in bloom? It is not a rare species. Both Michauxs, Andre and son, Francois Andre, had earlier described the fragrant white azalea that each found on mountain stream sides, but neither gave it a botanical name.4

R. canescens, the Mountain Azalea Pursh introduced another point of confusion when he took Michaux's southeastern R. canescens and applied it to 1812. Loiseleur's species is now named R. prinophyllum. high elevation plants in the Blue Mountains of Pennsylvania. It is generally not heat tolerant and resides mostly in This confusion lasted for over 100 years.3 [See Map 1] 5 northern climes or high elevations from western He apparently was not aware of the new species northeastward. There are, as you may know, disjunct Azalea rosea named by Loiseleur-Deslongchamps in populations in and southeastern . It

52 • The Azalean / Fall 2018 periclymenoides When aHybridisNot .TocallthisspeciestheFloridapinxteras because, withlittleornoverification,themappersrelyon pink intheflowerstoHenry Skinner,andhethoughttheywere previous publishedfloraandherbariumspecimens. York, butnoonecanorhaspointedtoindigenousplants. R. , andcollected and propagatedopenpollinated Bowers suggestedisquitemisleading.Manyifnotmostof Bowers arguedthat Handbook yellow azaleaonpropertytheHudsonRiver.Nooneelse above theCoastalPlain. and broughttotheColdenhamestateinNewYork? the pinkazaleasinFloridaaretetraploids,probablya that misinformation originatedfroma1749Latindescriptionof the mountainazalea. R. canescens, Carolina southwardandwestward.?ThisNewYorkerdid hybrids of headwaters oftheChoptankRiver. have misidentifiedplantsashybridswhentheyare just he wouldhaveknownaverylargeportionofthebiomass not havemuchfieldexperienceintheSoutheast.Ifhehad, has beenabletoofferevidenceof northern distributionofthespecies.Thisrepeatedpiece original plantscamefrombetweenDover,Delaware, and the of . Sheshowedaparticularly attractiveformwithsome suffice. PollyHillintroducedtheChoptankHybrids. The species showingofftheirvariability.Twoexamples will directions, incompleteandfalsepositives.Youwillfind, canescens thatyoumaysometimessee color formof common azaleaintheSoutheastPiedmontfromTexasto common namePiedmontazalea. 1960 revisionaswellinlettersforthe1952 is becauseofthisconfusionbetweenprinophyllumand identification difficulttoimpossible,itisalsotruethat we for far northasNewYork.Wasayellowazaleadugelsewhere for example, I, wasahorticulturistfromNewYork.Inhis1936bookand Species maps Calendulaceum R. He assertedtimeandagain,intotalerrorIhavetosay, Clement Bowers,whomImentionedpreviouslyinPart canescens We nowknowthat While thepossibilityofnaturalhybridsmakesspecies She transplantedthemin hergardeninWilmington, Species distributionmapsoftencontainerrorsinboth I amgladtoseethatthemostusedcommonnametoday arborescens R. R. calendulaceum canescens canescens R. and FredericLee's1958 atlanticum R. resides inGeorgia,,andTennessee R. on theAlabamaCoast.Theseerrorsoccur Not inthePiedmont austrinum. is rareeveninPennsylvania,themost is adiploid,and theoffspringarealmost is thePiedmontAzalea,whichmost calendulaceum is limitedtotheCoastalPlainfromSouth R. is oftenreportedinthestateofNew canescens crossed with atlanticum should notbecalledbythe calendulaceum throughout Alabamaand R. R. The AzaleaBook, periclymenoides. is atetraploid, canescens The Azalea growing as 6

called All FlowerBudsareChestnutBrown Will theRealTetraploidsPleaseStand? buds aregloboseandlooklikemusketballs.Somehave because Ihavelookedatflowerbudsasoneofmany portion oftheCoastalPlain. pubescence. Somehaveciliaalongthebudscales,andin R. with thenumberofsetschromosomesaplantoranimal with Hybrids tobetetraploids,andwehavemorefieldexperience accurately. and labresearchdiscoveringanewtetraploidspecies, and othersdoubtingthisfinallywithenoughfieldwork always triploid.RecentteststodatehaveshownChoptank and today atCallawayGardensinfrontof that werecalled tetraploid. Pinkdoesnotautomaticallymeanhybridization to bean to knowpinkisnotuncommonin twice thenormalnumberofchromosomes. Even thentheyareextremelydifficulttovisuallycount colemanii. canadense has. Youhavetwo.Plantscantwo,three,four,five, of course,knowthestoryJohnThornton,RonMiller, so smalltheycanonlybeseenwithanelectronmicroscope. six, ormore.Rhododendronchromosomesareverysmall, some casestheciliaareglandular.Somehavedarkbands statements onazaleaflowerbuds.Thiscaughtmyeye characters tohelpdistinguishonespeciesfromanother. Some arelanceolate;somequiteovoid. austrinum, colemanii, flower budsareovoid.Some,like V Photo2—Toomany canadense With advancedtechnologywenowknow I havementionedploidyseveraltimes.Ploidyhastodo In southernAlabamaandintoGeorgiathereareazaleas In Kron'srevisionof The firststudiesmademistakes. `Snowbird', acultivarattheBiltmoreEstatewassaid R. R. austrinum periclymenoides, atlanticum-canescens is diploid. However, therearestill were declaredtetraploids,meaningtheyhad R. were saidtobediploid. alabamense ovoid thanothers. and references simplystatenativeazalea or with calendulaceum Pentanthera The Azalean / cross, yettestsshowittobe or R. R. alabamense atlanticum. canescens canescens R. R. R. calendulaceum alabamense colemanii are tetraploid. are interesting are muchmore in thesouthern Fall 2018 • R. Vaseyi hybrids. You, atlanticum, atlanticum plants. flower labels and 53 R. R.

photo Charlie Andrews "chestnut brown." be thebestdivisionofourazaleasintospecies,westill have Yet, ineverycase,Krondescribestheflowerbudsas along thetopof always eglandular.Iwillexplainthealmostpartlater. many otherunansweredquestions. things wedon'tknoworunderstandaboutthiscomplex to distinguish however, withthisoldwivestale.Howoftenhaveyouheard sheets ofdriedspecimens.[SeePhotos4&5] group ofplants.Inadditiontothepuzzlementwhat should glandular. Newgrowthontypical chestnut brownnativeazaleaflowerbudsisonherbarium 54 •The Azalean/ is simpleandeasy.Newgrowthon it saidwhentheplantisnotinbloomalmostimpossible Can't Tell ► For Now,WeSeeThroughaGlassDarkly: fine softhairs. More examplesofmisinformationexist.Weshallend, We nowmovefrommisinformationtoanotherissue: I findavarietyofcolors,fairlyconsistenttothespecies. How did Highway. Yet,itwasnotrecognized asaspeciesuntil and manysettlementsupthe coastandalongtheKing's acre ormorewithits'runners. to Georgia.Thisisanearlyblooming,low-growing, the CoastalPlainfromsouthernNewJerseydown highly colonizing,fire-adaptingplantthatcancoveran R. viscosum. settlers andsoldiersfrom Jamestown,Charlestown, 1917, probablybeingconfused withthelater-blooming ♦ Of historicinterestis It hadtohavebeenstepped onbythousandsof Photo 3—R. austrinum Unanswered Questions atlanticum R. austrinum R. and usuallynotpubescent. 8 periclymenoides TheonlyplaceIhaveconsistentlyseen canescens Fall 2018 bud scales.[SeePhotos2&3] hide solong? From from is alsousuallycoveredwith R. atlanticum. buds areusuallynotasfat R. canescens? canescens canescens austrinum It growsin In fact,it is almost is always

Photo Charlie Andrews viscosum ► ► ♦ Where are Why does triploid hybrids? V Photo4&5—.Thesedistinctivewinterflowerbudsof with ayellowblotch,thereareveryattractivemulti- Almost notriploidsinareas of are tetraploid,andwhenthey pollinateadiploidazalea as high9,000feetatDonnerPass.Intheeast,wefail triploid hybridswith the resultisalmostalways atriploid.Manynatural have beendiscovered. Isthisbecause of adifference need? GreatBritainseemstosucceedwiththisspecies. north andsouth.Soil?Whatspecialconditionsmight it grow thisspeciesintheeast.Thereasonremains occidentale. colored forms.Wehaveneverbeenabletosuccessfully elusive. Climate?Inthewest,itgrowsoncoastand We know The onlynativeazaleaontheWestCoastis and Winter budscanaidinspeciesidentification. R. R. occidentalefail calendulaceum R. austrinum calendulaceum, austrinum, Though thetypicalformisawhiteflower calendulaceum (below) arenotchestnutbrown. and austrinum on theEastCoast? R. atlanticum have beenfound. and and atlanticum atlanticum R. R.

Photo Charlie Andrews Photo Bethany Plyler in the tetraploids? Is it because we simply have yet to recognize a possible natural hybrid and send a sample for testing? Notes on Introgression

► Yellow River vs. Escambia River R. austrinum Introgression is the infiltration of the genes of one In the lower section of the Yellow River in , species into the gene pool of another, usually through the tetraploids are all pink. Going up river, a transition backcrossing of an interspecific hybrid with one of its eventually occurs with a mixed area of pink, white, parents. and yellow. Farther up only yellow austrinum are Upward introgression: Introgression from diploids found. The Escambia River is not far away, but the into species of higher ploidy, commonly thought of from situation is quite different. Here, austrinum occurs in diploids to tetraploids (via fertile triploids). mixed colors all along the river: yellow, pink, white, and multicolored. Change in acidity does not seem to explain this difference.

► Is R. canadense really an azalea (or is it even a Rhododendron)? We have always known the delightful Rhodora, popularized by Emerson in his poem, was unique. Alarm bells went off at the 2013 joint ASA/ARS convention in Asheville when Jason Lattier, one of Dr. Tom Ranney's graduate students presented

results showing R. canadense appears to have a base ws

chromosome number of 12, not the uniform base dre number of 13. The sampling covered multiple locations An across the geographic distribution. If this holds true, it les

begs the question: Should canadense be considered an Char azalea? Is it even a Rhododendron? to Pho ♦ ► Should vaseyi be considered one of our azaleas? Photo 6—Above is an example of possible upward R. vaseyi is another plant that we know is different. In introgression, from diploid to tetraploid. DNA analysis may be the 2005 revision of Rhododendron, Loretta Goetsch et able to verify the conjecture. al. moved R. vaseyi out of Pentanthera. In their analysis, Downward introgression: Introgression from vaseyi was more closely related to plants formerly in polyploids into species of lower ploidy, commonly Menziesia than our other American azaleas.9 If true, thought of from tetraploids to diploids (via fertile this places some doubt on our even calling vaseyi an triploids). azalea. ► How does color relate to species? When is a blotch a sign of hybridization or introgression? Is the pink tetraploid in north Georgia R. calendulaceum? Is the pink tetraploid in the Florida Panhandle R. austrinum? Recent Research/Discoveries Since we have known about our native azaleas for over 300 years, we may tend to think we know them well. While

questions remain as we still see through a glass darkly, in ws fact, we are learning more every day. dre An

New Species les R. eastmanii was declared a new species in 1999. For Char years it was said to be a disjunct group of R. alabamense. to

The aforementioned R. colemanii sat quietly in the Red Pho Hills section of Alabama until someone finally realized R. ♦Photo 7—Above is a Cherokee County Georgia diploid alabamense grows in different habitats. It became a new (repeatedly tested) that has morphological features of R. species in 2008. calendulaceum, a tetraploid: large flowers, wide petals, flat open face, blotch. There were many triploids in the immediate area, a sign of R. calendulaceum x R. Pink Tetraploids = R. austrinum? canescens hybridization, thus suggesting possible downward In Florida, John Kunkle Small, Henry Skinner, and all introgression from tetraploid to diploid. others have assumed any Deep South pink azalea was R.

The Azalean / Fall 2018 • 55 canescens. Detailed field examination recently has revealed not and cannot accurately represent the entire populations of them to be wrong. Ron Miller discovered the pink tetraploids live plants. that in every other aspect are identical to R. austrinum. Applied Multimedia Technology Canl and Can2, Two Southern Pink Diploids We need a modern replacement for herbarium specimens Even more recently as Ron Miller explores the rivers, as the primary source of data. Using dried specimens was fields, and woods with an eagle eye, he has discovered that advanced technology in the 16th century. They show only there are two types of southern pink diploids. We call these a snapshot or two in the annual cycle of the plant. Much Canl and Can2. is lost in the dried evidence. A specimen may not represent Canl: This is the typical R. canescens. It has pink to white the typical population or the peak bloom and thus may be flowers with glandular hairs on the flower tubes and often misleading. With such scant evidence, the plant may be twisted, revolute petals. New growth is eglandular, distinct misidentified by the author and those who examine it. from R. austrinum. I am not suggesting we eliminate herbarium specimens but Can 2: Then in eastern , Ron discovered pink supplement them with 21st century multimedia technology azaleas with glandular new growth. To his surprise, ploidy with databases of morphological characters and habitat, GPS tests showed these plants to be diploid. Looking much like records, and digital habit, landscape, and both macro-lens canescens, these Can2 plants reside in a moister habitat, tend and microscopic images. to have broader petals, and are quite stoloniferous. Can2 More Ploidy Testing plants are predominant to the west in eastern Texas and We need much more ploidy testing, especially on wild northern . They occur only rarely eastward where plants, to better understand what is happening between Canl dominates. Should Can2 be considered a new species? our tetraploids and diploids. We need to find more fertile triploids and analyze the population around them to better Ploidy Research understand how these triploids naturally occurred. We need Recent ploidy research has opened our eyes to a better to fmd further evidence of downward introgression and understanding of possible species and hybrid relationships. upward introgression from tetraploid to diploid and vice It was the 2007 research of Jeff Jones, another of Dr. Tom versa. (See sidebar examples.) Ranney's graduate students, that revealed atlanticum, austrinum, and calendulaceum are tetraploids with twice the Hybridization Research usual number of chromosomes.10 Soon, the aforementioned We need more hybridization research. Systematic colemanii was added to the list. hybridization by humans can help us better understand what John and Sally Perkins joined with a team at the University has been and is going on in nature. of Coimbra in Portugal in an ongoing multi-year study of Rhododendron ploidy. By testing hundreds of and wild plants, and the Perkinses making crosses with parents Extensive DNA testing of known ploidy, they have come up with some general Finally, and perhaps most importantly, we need extensive ploidy rules. Their ploidy research is a presentation in itself, DNA research on our native azaleas. Such studies will require and I am anxiously awaiting their publications. Here are just careful controls to assure large quantities of samples, known a few derived observational rules: provenance of the samples, known character differences among and within populations, and geographically diverse • diploid x diploid = usually diploid populations. It is my hope that from these studies we can • tetraploid x tetraploid = usually tetraploid learn how related our 17 species really are. • diploid x tetraploid = usually sterile triploid Our ASA Research Fund can help support such studies. • tetraploid x diploid = usually failure Your contribution can help. See information on the ASA website: https://www.azaleas.org/research/arf-mission/ • fertile triploids can occur but are rare I hope you now see our native azaleas are indeed a very • triploids can produce diploids, triploids, tetraploids, complex group. We still have much to learn about them. pentaploids Thank you for indulging me with my love of these beautiful • In diploid x tetraploid Fi's, offspring tend to look azaleas. more like the tetraploid parent Notes and References New Research Needed 1. Linnaeus, Carl. Systema Natura. 1735. Lugduni That was an overview of recent research. So, what is Batavorum [Leiden]: Theodorum Haak. p. needed to better understand these wonderful plants? 8; Linnaeus, Carl. Flora Lapponica, 1737. Amstelaedami [Amsterdam]: Solomon= Field research Schouten. p. 56-9. We need more field research. We need boots on the ground, studying populations in situ. Too much of the previous 2. Lirme, Carl von (Linnaeus). Smith, James research results was based on herbarium specimens that do Edward, translator. Lachesis Lapponica or A

56 • The Azalean / Fall 2018 Tour in Lapland. vol. 1. 1811. London: White American Province of .] Acta Societatis and Cochrane. p. 284-5, 291, 299-301. Project Regiae Scientiarum Upsaliensis, 1749. p. 93.] Gutenberg eBook < https://www.gutenberg.org/ ebooks/34779 >. 7. See for example, Bowers, Clement Gray. and Azaleas: Their Origins, 3. Pursh, Frederick. Flora Americae Septentrionalis, Cultivation and Development. 2nd ed. New York: or A Systematic Arrangement and Description of The Macmillan Company. 1960. p. 249. the Plants of North America. vol. 1. 1814. London: White, Cochrane, and Co. p. 152-3.] 8. Kron, Kathleen A. "A Revision of Rhododendron Section Pentanthera." Edinburgh Journal of 4. Michaux, Andre. Sargent, Charles Sprague, ed. Botany. 1993. 50(3): 249-365. Journal of Andre Michaux 1787-1796. Proceedings American Philosophical Society. 1889. 26(129): 9. Goetsch, Loretta, Eckert, Andrew J., Hall, 116; Michaux, Francois Andre. Travels to the West Benjamin D., and Hoot, Sara B. "The Molecular of the Alleghany Mountains. in Early Western Systematics of Rhododendron (): A Travels 1748-1846. vol 3. Thwaites, Ruben Gold, Phylogeny Based Upon rpb2 Gene Sequences." ed. 1904. Cleveland OH: Arthur H. Clark Co. Systematic Botany, July 2005. 30(3): 616-26. (Reprint from London edition 1805.) p. 151. 10.Jones, Jeff R. Ranney, Thomas G. Lynch, Nathan 5. Map used by permission: The Biota of North P., & Krebs, Stephen L. "Ploidy Levels and America Program, North American Plant Atlas Relative Genome Sizes of Diverse Species, (US County-level Species Maps: List by Genus). Hybrids, and Cultivars of Rhododendron." Journal Kartesz, J.T. The Biota of North America Program American Rhododendron Society. Fall 2007. 61(4): (BONAP). 2015. Taxonomic Data Center. (http:// 220-7. www.bonap.net/tdc). Chapel Hill, NC. [Maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of Charles Andrews of Cumming, Georgia, is vice president of the North America Program (BONAP). (in press).] ASA, a member of the Vaseyi Chapter of the ASA, and a former member of the Oconee Chapter. He is a plant lover in general, 6. Colden, Cadwallader. "Plantae Coldenhamiae but his heart is with azaleas. He enjoys writing and speaking on in provincia noveboracensi americes sponte azalea topics, contributes articles to The Azalean, and serves on crescentes." [Plants of Coldenhamia in the the journal's Editorial Advisory Board. He is also immediate past president of the Azalea Chapter of the ARS. For over 35 years, Charles has been studying American deciduous azaleas. He and like-minded "azaleaphiles" spend many hours hiking in the field each year trying to better understand the distribution, habitat, characteristics, and dynamics of this amazing plant complex, primarily found in eastern North America. He believes these plants deserve more scientific study and horticultural emphasis. Charles is working to make accurate information on the history, identification, distribution, and culture of native azaleas more available. Deadlines for input for The Azalean April 1- bON'T You are cordially invited to join the Summer 2018 Issue MISS THE American Rhododendron Society `)EADLINE! Benefits: quarterly journal, exchange, July 1- chapter affiliation, conventions Fall 2018 Issue Email: [email protected] Postal: P.O. Box 214, Great River, NY 11739 October 15-Winter 2018 Issue

ARS Website: http://www.rhododendron.org December 1-Spring 2019 Issue

The Azalean / Fall 2018 • 57