VASCULAR PLANTS ON A GYPSUM OUTCROP IN SOUTHERN NEW MEXICO: A LISTING, A NEW VARIETY AND TAXONOMIC REALIGNMENTS IN THE ANULOCAULIS LEIOSOLENUS COMPLEX (NYCTAGINACEAE), AND A NEW VARIETY OF MENTZELIA HUMILIS (LOASACEAE)

13 Pages·1999·6 MB·English

by  Richard Spellenberg

VASCULAR PLANTSONAGYPSUMOUTCROP IN
SOUTHERNNEWMEXICO: ALISTING, A NEW
VARIETYANDTAXONOMICREALIGNMENTSIN
THEANULOCAULISLEIOSOLENUSCOMPLEX
(NYCTAGINACEAE), ANDANEWVARIETYOF
MENTZELIA HUMILIS(LOASACEAE)
RICHARDSPELLENBERGandTHOMASWOOTTEN
DepartmentofBiology
NewAlex/COStateUnii'ersity
LasCmces. NM88003-8001. U.S.A.
ABSTRACT
Asurveyoftliefk)raonahithertounexploredt^'y|istimoutcroponthewestfaceofthe
GuadalupeMountainsinsouthernNewMexicohasrevealedanewvarietyoiAi/z/Iocaul/s
(Nyctaginaceae),A.kioiolmiis(Torr.)Standi.var.howardiiSpellenb.&Wootten(var.nov.).
Thisvarietyhasacombinationofchatacteristicsinvariousdegreesintermediatetoother
taxa,anobservationthatresultsinthemtlusioni){A.gypiogeunsWaterf.intoA.Ic/osolou/s
asA.leiosoleniisvar.j^ylno^eiius(Waterf.)Spellenb.&Wootten(comb.nov.).Alsofromthis
outcropisdescribedMeutzelicibiiniilis(A.Gray)J.Darl.var.g/iachilz/peiisisSpellenb.(\ar.
nov.).Fifty-ninespeciesin29famiheswereobservedrooccuronthegypsumoutcrop.A
keyisprovidedtoallknownA}iiilinciiiHstaxaandalistispresenteddoctimentingtheother
plantspeciesthatoccurwithitandthenewvarietyofAl.h/nuilis.
Rr.SMMF.N
Laexploracionclelafloraentinafloramientock-yeso,inexpl(M-adopreviamente,enla
laderaoestedelasMontaiiasGuadalupeenelsurdeNuevoMexicohareveladounavariedad
nuevadeAnnloan/lis(Nyctaginaceae),A.leiosiileiiiis(Torr.)Standi,var.howardiiSpellenb.&
Wootten(var.nov.).Estavariedadtieneunacombinaciondecaracteresintermediosenvarios
gradosconotrostaxa,unaobservacioncjueckicomoresultadolainclusicSndeA.gypsogei/us
Waterf.enA.kioioleiuaasi'comoA.Iciosoloii/ivar.gy/>sogi.'////s(Waterf)Spellenb.&Wootten
(comb.nov.).Tambicn,Meiitze/iah/tiiiilis(A.Ciray)J.Darl.var.guudalnptiniiSpellenb.(var.
nov.)estack^scritadeesteafloramiento.Cincuentaynueveespeciesde29familiasdeplantas
fueronobservadasenesteafloramienrodeyeso.Seofreceunaclaveparatodoslostaxaconocidos
deAnulocaiilisysepresentaunalistadocununtandolasotrases|-ieciesde|-)lantascjueconviven
conlasdosvariedadesnuevas.
INTRODl'CTION
Whiledeerhuntin^^insouthernOteroCounty,NewMexico,aboutadecade
ago,MichaelHowardoftheBureauofLandManagement,LasCrucesDis-
trict,traversedagypsumoutcroponthewesternslopeofthenorthernpor-
tionoftheGuadalupeMountainsandnotedanAn//loca/dis.Inthesummer
of1996heshowedtheplanttoWootten,whocollectedavoucher,identified
SiDA 18(4):987-999.1999
9<ScS Sum18(4)
theplaiirasAfu//ou/////si^ypsoi^c/zusWacerf.,andbroughtittotheNewMexico
State University herbarium Fordeposition. Spellenberg immediatelyrec-
ognized theplantasnearA. i^^ypsoi^o/usbutsomewhatdifferent.Thatcol-
lectionalsobroughtattentiontoapreviotislyunbotanizedareaonthewest
faceoftheGuadalupeMountains.
WoottenandHowardvisitedthesouthernportionofthegypsumout-
cropinSeptemberandNovember, 1996,andescortedSpellenbergtothat
siteinearlyAugtist1997.SpellenbergandWoottenrettirnedtothesouth-
ernportionoftheoutcropinSeptember 1997and April 199H,andtothe
northern,morelengthyportionoltheotitcropinJuly, 1998.Otirsm-vey
re-vealednewvarietiesoiA)////ou/////.\'leiosuleniisandMeinzi'l/al.y/iiiih/s,herein
described,andresulted inacollectionolplantsdocumenting thefloraol
thisgypsumoutcrop(A[-)pendix 1).
CIlARACriT.Rl.STlCSANDfLORAOFCYPSUM()Lfrc;R()P
ThisgypsumoutcropispartolthePermianageYesoFormation(Hunt
1977). Mostoftheoutcropconsistsollimestonerubble,thestones2—10
cmindiameter,orlarger,overlyingapaletan,sandy,gypseousclay.Inafew
l^laces,whenwalkedupon,thegypsummakesthehollowsoundcharacter-
isticofothergypsumoutcrojisintheSouthwest.Onthesteeperslopesthere
islittlelimestonerubble,thegypseousmatrixbeingcompletelyexposed.
tioTnsh.eTohuetcsrooupthiesrnnostecctoinotnineuxotuesnldysleoxrpaobsoeudta5ndkmconisnisatNsoNlWtwo-SmSaEindirseecc--
tion,andperhapsupto3/4km inan R-Wdirection,withanelevational
rangeofabout 250 meters beginningatabout 1350 m. Itoccurson the
lowerslopesofthewesternescarpmentoftheGuadalupeMotintains,be-
neathTheRim,attheupperedgeolthebajadasthatextendwestward to
(j'ow flats.Thesouthernendofthissectionliesabout4(SairkmNNEol
DellCity,Texas,centeredonabout 32"22'N, 105"04'W(Sec. 25 toesti-
matedSec. 11,T22S,R18E),justnortholthemoutholPupCanyon.Most
oftheoutcrop hasaverysteepwestern expostire, theslopes 30—15**and
steeper. Nearthebaseoftheoutcropat thesouthernendoltheoutcrop,
andalsoabout2 kmtothesotith,therearealewlow,gypseoushillsthat
haveslopesolallexposures,andwithinthemajorportionoftheoutcrop,
gullysandarroyosprovidenorthernandsouthernexposures.
Thesotithernportionoltheoutcropdisappearsnearthenorthernendofa
smallsouth-lacingboxcanyon.Itorasimilargy]^seousoutcropreappearson
thewesternslopesolthemountainsabout3kmtotheNNW.Fromthere
theoutcropcontinuesinanorthwesterlydirectioninacliscontinuotismanner
forTahbiosutout1c2rkopmo(cSceuc.rs33m,Tan2r1eS,moRte1<aSErenaowrhtehrwearadccteossSeics.c2o5m,paTr2a()tSi,veRlyI7dEi)f.-
ficult. Theentireotitcrop lieson pLiblic lands,someportionsentirelyon
Spfli.f.nberc;andW(X)tten,Vascular|-ilantsinsouthernNewMexico 989
thoseoftheBureauofLandManagement,LasCrucesDistrict,inotherar-
eastheeasternportionson theGuadalupeRangerDistrictoftheLincoln
NationalForest. Browsingofafewofthespeciesthatoccuronthisout-
crop,probablybydeerand rabbits,wasnoted; nosignofdomestic Hve-
stock,commoninthevalleybelow,wasobserved.Accordingtoalocalrancher,
Mr.GeorgeRanch,thelivestocksimplydonotgetuptothisratherinhos-
pitablesite(hewasspeakingofthesouthernsection, butconditionsare
similaralongthelengthoftheoutcrop).Thetwonewendemicsdiscovered
herepresentlydonotseemtobeimpactedbyhuman-relatedactivities.
TheAnulocatiinandtheMentzeliaarebothcommonandconspicuouson
theoutcrop.Becausetherearenorecordsincollectionsofthesetaxafrom
here,webelievethattheoutcrophadnotbeenexploredbybotanistsprior
toourwork.Onlyaminorportionoftheoutcropconsistsofhighlycon-
centratedgypsum,andhereobligategypsophilessuchasA.leiosolenus.M.
humilm,andSelinocarpuslanceolatmoccur.Onthisportionwedocument59
plantspeciesin29families(Appendix1),includingthetwonewvarieties
describedbelow.Westoppednotingspecieswhenwecrossedoffthegyp-
sumandontothecobblylimestonebajadasthatsupportChihuahuanDesert
vegetation consistingofLarreatridentata(DC.)Gov.,Partheniumincanum
Kunth,AcacianeovernicosaIsely,FoNciuieriasplendensEngelm., Yuccatorreyi
Shafer,EphedraasperaEngelm.,DasylmonwheeleriS.Wats.,Echinocereuspectinatus
(Scheidw.)Engelm.,KrameriaerectaWilld.exSchultes,Allioniaincarnata
L.,StenandriumbarhatumTorr.&A.Gray,PolygalamacradeniaA.Gray,among
numerousotherspecies.
ANEWVARII-TYANDTAXONOMICREALIGNMENTSINANULOCAUI.IS
Spellenberg(1993)providedataxonomicreviewoiAniilocaiilisandrec-
ognizedfivespecies,oneofthem,A. leiosolenus,withtwovarieties.Turner
(1993)describedasixthspecies.Thispresentpaperreducesoneofthespe-
ciesrecognizedbySpellenbergtoavarietyinA.leiosolenus,andaddsafourth
varietytothatspecies. WenowconsiderAnulocaulistohave fivespecies,
onewithfourvarieties.
Anulocaulisleiosolenus(Torr.)Standi,var.howardiiSpellenb.&T.Wootten,
Cviatny,nTeoxva.s,TyWf!-baUseNoIfTGEuaDdaSlTuApTeESM.rs.N,eNwoMfemxiocuot.hOotlePruo|tCoC.a:nyIoSn,kmca.N5N0EmoSfWDelolf
NEcornerS26,T22S,R18\V,32"22.14'N,105"03.92'W,elev.1360m,5Aug1997,
Spelknherg.Wootteti,unciHoward12433(holotype:NMC;is()iypi:s:NY,TEX,UNM).
AAnulocauleleiosolenovar.leiosolenoperianrhiisrubro-roseis(vs.albisvelsubroseisdikitis)
foliislevirerglaucisetparceruberculatis(vs.viridisnonglaucisetdenseruberculatis)differt.
Strongperennialfromgnarledwoodyroot.Stems1-ca.6,ascending,branched
inupper70%,uptoca. 1.2mtall,glabrous,glaucous.Leavesusuallyin2-
3pairsinbasal 1/4ofplant;petioles35-50mmlong,bladesmoreorless
990 SiDA18(4)
orbicuhir,commonlywiderthanlong,45—105mmlong,45-135mmwide,
scmi-giuucous,bluish-green,withsparsepurplishpustules,pustulesslightly
denseronabaxialsurface.Inflorescenceswidelypaniculate,formingtheti]")-
per2r:yoftheplant,theflowersborneterminallyandonshortsidebranches
in more or less congested clusters. Budswith minute hairsat theapex.
Perianthdeeprose-pink,obHquelyfunnelform,22—32mmlong,limb10-
17mmwide,stamensexsertedca.20mm,thestyle25mm.Fn/itbiturbinate,
4.3—5.9mmlong,3-7—4.5mmwide,with 10irregularlongitudinalridges
andanequatorial wing0.2—0.9mmwide.
Atpresent,thenewAnz/IoccN/I/sisknownonlyfromthewesternslopeof
theCjLiadalupeMountainsinsouth-centralNewMexicoontannish,shaley,
gypseousclays,andthenonlyfromthesouthernportionofthegypsumoutcrop,
immediatelynorthofPupCanyon.Explorationoftheoutcroptothenorth
revealednootherpopulations.Wenametheplantforitsdiscoverer,Michael
Howard,oftheLas Cruces District ofthe Bureau ofLandManagement,
whoseattentiontonaturalbiotaresultedinthediscoveryofthisAniilocaulis.
Mikehasastrongsenseofresponsibilityforthenation'snattn-alresources,
shareshisknowledgewillinglywiththepublic,andworkstowardmaking
land-useintheSotithwestcompatiblewithneedsforconservation.
Paratypks:NI-WMI'XICO.OteroCo.:ca.30airmiNl-oflX-llCity,Texas,foothills
oICf^CSiieKpul1al9i9i6p,eWMotontst.enatciimiodtHiotwhuonflPsu.np.(CNanMyCo)n;,4c8xtkrcmmLN-NSFE.coofrnDeerllolCiSteyc,2T3e,xaTsi,iWS,bRa1s8eEo,f
GuadakiiieMts.,NofmonthofPupC^anyon,edgeofLincolnNationalForest,t;i.300m
SEWpeNllEbeausboeefvoySl^.CWiWuocaoodtratnlaeuirpaeSm2MiitsW.Tn,w2cN2iSnollRm/1o284uWit,5ho(hfATPRluILZp,lCVaNnHMy,oCn,.10UN'C)E")7;S1e4'c9W2,k3,emlTe2Nv.2NS1,E3R6o(f1)8DmWe,l,l53C2Ai"tu2yg,2.T71e59x'9aN7s,,,
1()5"0t.99'W,elev1460m,5AugI997,%/AW;c;;i,', W(mtte>iandUnwcm!I24^i^{VMC).
Annlocaulisleiosolenusvar.boivarcliiisimmediatelydistinguishablefrom
closerelativesbythecombinationofthesemi-glaucousleaveswithonlya
fewlargemulticellulartrichomes,thereddish-pinkperianth,andthemoderately
broadrimonthefruit(Table1).Thefruitismostsimilartothatillustrated
inSpellenberg(1993,Fig. IF),afruitfromaTexasraceofA.leiosolenusvar.
leiosoloius.Withinthecomplex,minutehairsatthetipoftheperianth,best
seeninbtid,werepreviouslyknownonlyinthevar.hisianthus.
AsillustratedinTable 1,thenewvarietyhassomeofthecharacteristics
thatareusedaloneorincombinationtodistinguishamongothermembers
oftheA.gypsoi^eniis-leiosoleiuiscomplex(Spellenberg 1993)-Forthisreason
webelievethenewlydiscoveredentityisbestrecognizedasavarietyina
morebroadlyreconstructedA.leiosoloius^inwhichA.gypsogenusisinclucfed
atthevarietallevel.Theentirecomplexpresentsaclassicrepresentationof
completelyallopatric,closelyrelated,moreorlessdistinguishableraces,this
structurecommentedujionbySpellenberg(I993).Mayr(1969,ch.3)dis-
Speuj-nbhrga\dWootti-n,VascularplantsinsoiirhernNewMexico 991
Tablr1.Acomparisonofsomecharacteristicsusedtodistinguishvarieties
withinAnnlocal/lisleiosolem/s.
VarietyoiA. Perianthlimb l^erianth Leaves Fruitwing
leiosoloiiis color pubescence
i^^yspsiigi-Hus whitetovery none palebluishgreen, 0.8—1.2mm
palepinkish glaucous,smooth,
palegrayorwhitish
whendried
•cl'ii deeprosepink minutetrichomes bluishgreen, 0.2—0.9mm
attipinbud semi-glaucous,
tewlargeconical
tubercules,grayish
greenwhentlried
Uisiauthns palepinktopink minutetrichomes green,semi-glaucous,
attipinbtid denseconical 0.2—0.6mm
tubercules,dtill
greenwhendried
kinstilenits whitetopalepink none green,notespecially 0.2-0.6mm
glaucous,denseconical
tubercules,dtiUgreen
whendried
cussedproblemswith '^:'cidingtaxonomicdivisions inaUopatricpopula-
tions;Stuessy(1990,ch. 12)discussedproblemswithassigninginfraspe-
cifictaxatovarietiesorsubspecies.WithregardtoAnidocaidis, thetradition
ofusingvariety is followed fortaxonomic recognition ofcloselyrelated,
internallyratherhomogeneouspopulationsthatcanbedistinguishedfrom
other,similarpopulations.
Spellenberg(199.^)notedthesimilaritybetweenthelarge,paleperianth
ofthewesternraceofA. leiosolenusvar.leiosolenusandthatofA.gypaogenm.
Onamoresubtlenote,thevar.hoivardiihasflowersclusteredintheinflo-
rescencereminiscentofvar.lasianthiis.Thischaracteristicissomewhatde-
velopedinA.gypsogen/tsandmtichlesssointhevar.leiosoleru/s.Theleavesof
thevar.howardiiaremoresimilartoA.gypsogem/s.Thefruitsareratherin-
termediatebetweenA. leiosolenusandA.gypsogenus,astraditionallyrecog-
nized.Itisourviewthatwiththediscoveryoftheeasilyrecognizablerace
nownamedasA. leiosolem/svar.howardii,theotherphasesinthiscomplex
ofgypsophilicendemicsarebestrecognizedasbelongingtoonegeographically
fragmented(Fig. 1)speciesofvariablydifferentiatedallopatricraces. For
thatreason,wetransferA.gypsogeni/sintoA.leiosolenusasavarietyrestricted
tothegypsumalongthePecosRiver,slightlytotheeastof,butcompletely
disiunctfromvar.howardii.
992 SiDA18(4)
BAJA
CALIFORNIA
S
Dvar.gypsogenus
#
var. howardii
var. lelosolenus
Ovar. lasianthus
\
Fic;.1.Mapofstatesof.soLithwcstcrnUnitrtlStaresandnorthwesternMexieoshowmi;rhe
distributionofAniilociuil'isUnisoleiiiisvarieties.
Anulocaulisleiosolenus(Torn)Standi,var.gypsogenus(Watert.)Spellcnb.
6T.Woottcn,comb. nov.Basionym:AiuilDcmlhgyp^ui^ciiiisWarcrl'.,RhoLJora
47:329.I943.Tvpi-:UNITEDSTATF.S.Ni:wMf.xko.CliavesCxi.:ComancheanBluHs,
7miEofRoswell,9Ocr1944,\VcilerfaH570I(iioLcnvpi::(IH!;i.seriM'i.s:NY!MO!),
KI:Y'IX)TAXAOl-AMU.OCAIUJS
1.A1n6tmlimoeaIrophlw;,itrhhoeutloabepsroflmairinuei;ntbuercjunaottorrieafllerxieccllj.^eorwmy;perianthlessthan
2.Perlanrh 1)—16mmIoul;aranrhesis,purplish,thetubeexternallygla-
brous,minurelyglaneiular-pubescentnearrheapex;anthocarj^ellipsoid
orbroadlyhisiform(southernCoahuila) A.hintoniortimB.L. llirner
2.Perianthlessthan 10mmloni;atanrhesis,whitishrorose-lavender,rhe
tubeexternallyvilloirs;anchocarphrsiiormorrurbinare.
3.I'lowersusually3-13intimbel-likeclusters;tubeolperianthnotelongating
afteranrhesis;anrhoc.u'pbroadlyfusiform(southeasternCalifornia).
A.annulatiis(C'oville)Standi.
3.Idowerstisuallybornesingly;ttibcofperianthmarkedlyelongatingafter
anrhesis;anthocarprtirbtnate,bluntly3-angled,ridgesindefinite(southern
'lexas,western(Coahuila,possibheasrernChihuahua) A.eriosok-ntis
(A.Ciray)Standi.
1.Anchocarpwithaprominentequatorialridgeorwing;perianth1()-s3mm
long,thelobesflaringorsharplyrefiexeel.
Spin.LENBHRGANDWooTTRN,VascularplantsinsouthernNewMexico 993
4.Perianthca. 10mmlong,thelobessharplyreflcxed(northeasternChi-
huahuaandimmediatelyadjacentTexas) A.reflexusI.M.Johnst.
4.Perianth22—35cmlong,thelobesflaring,notreHexed A.leiosolenus
(Torr.)Standi.
5.Leavessmooth,glaucous;perianthglabrousexternallyatapex(Pecos
RiverinsouthesternNewMexicoandwesternTexas) var.gypsogcnus
(Waterf.)Spellenb.&TWootten
5.Leavesatleastsparselytuberculate;perianthminutelypuberulentor
glabrousattheapex.
6.Perianthglabrousexternallyattheapex(extremewesternTexas,south-
centralNewMexico,north-centralArizona,andsouthernNevada)
var.leiosolenus
6.Perianthminutelypubescentexternallyattheapex(visiblebestwhen
inlatebud).
7.aLnetahvedseegpraryoisseh-pginrkee(ns;ouptuh-rcpelnitsrhaltNubeewrcMuelxeiscoo,nWleafvaecseosipaGrusaed;apleurpie-
Mts var.howardiiS]:iellenb.&T.Wootten
7.Leavesgreenordarkgreen;purplishtuberculesonleavesdense;
perianthpalepinktopink(BigBendregionofTexasandimme-
diatelyadjacentChihuahua) var.lasianthusLM.Johnston
ANEWVARII-.TYOi'MF.NTZFJJAHUMIIJS
Mentzeliahmnilh(Urb.&Gilg)J.Darl.isavariableyetdistinctivemember
ofsect.BartoniaTorn&A.Grayrestrictedtogypseousstibstratesinsonth-
easternNewMexicoandwesternTexas(Thompson1997).Leavesvaryfrom
pectinatetoentire.Usuallyleavesinapopulationaresimilar,butoccasion-
allypopulationswillhavepectinateandentireleaves{Sivtmkiandhightfoot
2634:citedAientzeltaspecimenscompriseAppendix2).Leavesmaybeclearly
pectinate,thelobesdistantlyspaced and linear, 1—2mmwideandabout
15mmlong,orlobesmaybemuchshorter.Lobesmaybestraightorsome-
whatfalcate,curvingtowardtheleafapex.Ineithercase,themarginsofa
lobeareapproximatelyparallel and theapexofthelobeisalmostalways
rounded. In somecaseslobesarecompletelyabsentandleavesareentire
andlinear.Basalleavesmaybemuchlesslobedthancaulineleaves{Higgins
6845).Otherthanbyflowercolor(notgiven,butpresumablywhite)Higgins
6845,fromwesternTexas,cannotbedistinguishedfromapectinatelylobed
formofAl.perennisH.J.Thompson(ined.)fromcentralNewMexico{Edwards
andRepass4726:SpellenhergandWiUson4233:Wardetal.81-281),leaving
onetoponderthedistinctionofthesetwotaxa.
Specimens ofthiscomplex inNMC havebeenannotated as eitherM.
hunnlisorM.perenmsbyH.J.Thompson.MartinandHutchins(1981)separated
thesetwotaxaintheirkeyonavegetativecharacter,tufted(Al.perennis)vs.
nottufted(Al.humilis),afeaturethatwillnotdistinguishthem.Theygive
flowercoloroftheformeras"palelemon-yellow,"whichisapproximately
correct,vs."yellow"forM.himiilis,whichisincorrect(paleochroleucuous
994 Sum 18(4)
towhite).PerhapsMartinandHutchinswerefollowingtosomedegreeWooton
andStandly(1915)whonotedpetalstobe"paleyellow"(inNnttctllui<f[ypsea
Wooton&Standi.,asynonymofvM.hi/iml/fs),orDarlington(1934),who
"keyed"M.hum'ilisunder"flowerslemon-yellowtogolden."Thisasstmip-
tionofyellow-coloredflowersisunderstandablebecausebudsarccreamand
driedpetalsinfreshspecimensaredefinitelyyellowish. ThompsonandZavortink
(1970)maybethefirsttohaveindicatedthatAJ.hi/miliscorollasandandroecia
werewhite.LaterThompson(1997)describedthei:»etalsas"whiteorvery
paleyellow."Mentzeliaperemashaspaleyellowpetals.
In Thompson (1997) andThompson and Zavortink (1970),Meiitzelia
specimensfromthegypsumoutcrojidiscussedearlierkeytoAI.strictissJii/a
(Wooton&Standi.)J. Dark,burthisisaverydifferent,tallplanethatoc-
cursin(often)sandysoil.Ithasdentateleavesandcylindricalcapsules.Leaves
ofthenovelMentzeluimuchmorecloselyresemblethoseofAlii/cxiuniciH.
J.Thomjis.&Zavort.orAf.saxicola11.J.Thomps.&Zavort.asillustrated
inThompsonandPowell(1981,fig.7).Theseareyellow-floweredspecies
ofwesternTexasandnorthernMexicoonceconfusedwithAI.miihijhra(Nutt.)
A.Cjray.Unfortunately,ThompsonandPowelldidnotdiscusstherelationship
of/\l, hi/n/ilisroanyofthesespecies. Inastu'veyofotherspecimens,leaves
fromthenovelplants(romthegypsumoutcroponthewesternslopeofthe
GuadalupeMountains moreclosely resemblethoseofsomespecimensof
AI. Dudtiflora^andalsoresemblethat illustrated inThomjisonand Powell
(I9HI,flg.7)forthiss]iecies.
ThompsonandPowell(19HI)illustrated,described,andcompared the
seedcoatsofAl uiulttjlorciwithseedcoatsofAI. }}iex'h...uiandAI.saxicolci.
They noted thein-strohavecellswithswollenouterwallscoveredbynu-
meroussmallpapillae.Thisgivestheseedcoatacoarselygranularappear-
anceor, as stated inThompson(1997), it is "rough withpapillae." Seed
coatsofthelattertwohavefewerpapillaeantlappear"smooth"(Thom|">son
1997), buractually arevery finely granular undera microscopeatabout
2()x.Thomj^soncHdnotgivethecharacteristicsofseedcoatsofAI./v/w/7/j;
we note them tobeverysimilarto thoseofAl, Diiiltiflorci,asare theseed
coatsofthenovelMentzeluiinquestion.
Thompson,inattemptingtoworkoutdistinctionsbetweenNewMexico
populationsofyVI. multiflora. Al.jeu/ezeiisis, M. b/niiilis,andM. stricthsinia
sentSpellenbergaletter(29Apr1980),amap,andcolorphotographs(without
provenance)explaininghisinterpretation(hiedatNMC,accession#60536,
in/\I. jeDiezensis folder). Aleiitzel/diiu/ltifluraand /\1, biiiiiilishaveverydis-
tinctflowers,theflrstyellow(Thom]ison'sphotoismoreyellowthanmost
racesinsouthernNewMexico,whichmaybe]^aleyellow),A{.huiiiUisnear
white.MoreimportantAl.niiiltijiorahasbroaderpetalswiththetransition
tostamenswithexpandedhiamentscomparativelyabrupt,whereasAI.hiijiiilis
1
SpiiLLFNUHRc;ANDWooT'inN,VascularplanesinsouthernNewMexico 995
hasnarrowerpetals,thetransitiontostamensmoregradual.Flowersfrom
thenewMentzeliainquestionverystrongly resemblethoseofthephoto
andofspecimensofAl. hiiviilhandarenotlikethoseofAl.mtdtiflora.
Thompson(1997)indicatedcapsulesofAI, vmltifloratobecylindrical,
15-25 mmlong,whereashewrotethatM. huviJlhhascapsulescup-like,
6—13mmlong.ThenovelMentzeliahascapsulesthatarecup-shapedand
inthelowerrangeoflengthforthoseofAI.humilis.Plantsofthenewpopu-
lationaredenselyclumped,likesomeracesofAL hnmil'is, and leavesare
sub-entire,dentate,orpinnatiscct,reminiscentofthoseofAI.mtdtiflora.When
theleavesarepinnatisect, thelobestaperfromabroadbase toanarrow,
acuteorevenacuminatetip.TheflowersandcapsulesarelikethoseofAI,
humiin. Theinflorescenceismuchmorecongestedthaninanyofthespe-
ciesmentioned.
ThemapThompsonprovidedwithhislettertoSpellenberg(29Apr19H())
showsAI.humilistooccurinwesternTexasandeasternNewMexicointhe
PecosRiverdrainage,distinctly,butnotdistantly,eastofthepopulationin
question.HemaintainedthisdistributionforAI.hnviilhinhis1997manuscript.
Onhismapaccompanyingtheletter,AI.perennisisshowntooccurinalim-
itedareatothenorthwestofthesitefromwhichthenewMentzeliaorigi-
nates.Mentzeliamultiflora,incontrast,iswidespreadinthewesternUnited
StatesandnorthernMexico(Thompson1997).Itisknownfromrobustto
smallerplantsintheGuadalupeMountains{e.g.,Spellenberg3660, Wooton
s.n.).Boththesespecimenshavebroadpetalsandcylindricalcapsulesrep-
resentativeofthespecies;Spellenbergnotedflowercoloras"paleyellow"
onthespecimenlabel.InhisletterThompsonalludedtothepossibilityof
geneflowbetweenisolatededaphicendemicsandmorewidespreadedaphically
unrestrictedspecies.Suchaprocessmightexplaininthenewvarietythe
leavessimilartoAI. multifloraandtheflowersandcapsulessimilartoAl.
humilis. Observationsfromthesepopulationsrevealthatflowersandcap-
sulesofthenovelMentzeliaareconsistent,foliageandhabitarevariable.
Nevertheless,theraceisconsistentlydistinctfromAI, hunnUsvar.humilis
and isgeographicallyisolatedfrom it:var.humiliseastoftheGuadalupe
Mountains,var.guadalupensisrestrictedtothewesternslope.
Mentzeliahumilus(A.Gray)Darl.var.guadalupensisSpellenb.,var.nov.
C(iFtiyg,.Te2x)a.s,TyWpe:bausenoiftGeuaddaSlTuApTeEMSt.s.N,eNwofMemxoiuctoh.oOftPeurpoCCao.n:yo4n8,kSmANT2N2ESRof18DeWl,l
32"22.74'N,1()5"()4.26'W,elev.1460m.,22Sep1997,Spdknkrg&Wnotten12435
(iiolotvpe:NMC;isotyfes:NY,TEX,UC,UNM).
AMentzcliaehumilivar.htmiilifoliisdentatisvelpinnatisectis(vs.pectinatisvelintegris),
rachidibus2—8mm(vs.1—2mm)latibus,inflorescentiiscongestibus(vs.noncongestibus),
etplerLimquepedicelliscapsulisbrevioribus(vs.aequantibusvellongioribus)diftert.
Plants0.5—2.5 dmtall;basalleavesspatulate,dentate,with2—4teeth
996 Siiv\18(4)
?cm
Fk"..2.Illustrationof|-ilantscomprisingtiietypecollectionofMoitzelidhz/ruilisvar.g/hicLih/pensis
(Sj)ellenherii^&Wnotten124'^^)-Collectionwasmadewiththeintentofillustratint;thema-
joraspectsofvariationinthepoptilation:habitandleaftlissecrion.All|ilantsareclearly
identifiedmdistributedspecimensbysmalltagsaffixedtothem.Allplantsinphotograph
areatNMC.PlantAistheholocypeplant,whichhasbeenmountedseparatelyfromisotypes
atNMC;otherportionsofplantAhavebeendistributedwithotherisotypeplantstoKY,
UC;plantB,NMC,NY;plantC,NMC, NY;plantD,NMC,TEX,UC,UNM.Plants
similartoA-Carecommonmthe|-poptilation;plantswithleavesdissectedtotheextentof
plantDarelesscommon.