THE USE OF ANIMAL-DISPERSED SEEDS AND FRUITS IN FORENSIC BOTANY

12 Pages·1998·5 MB·English

by  Barney L Lipscomb

THE USE OFANIMAL-DISPERSEDSEEDSAND
FRUITSINFORENSICBOTANY
BARNEYL.LIPSCOMB
BotanicalResearchInstituteofTexas
309PecanStreet
FortWorth, TX76102. U.S.A. [email protected]
GEORGEM.DIGGS,JR.
DepartmentofBiology
AustinCollege.Sherman. TX75090, U.S.A.
&BotanicalResearchInstituteolTexas,[email protected]
abstrac:t
Aspecificcaseoftheforensicuseofanimal-dispersedpropagiilesispresented,anditis
suggestedthatthistypeofevidencedeserveswiderutilizationbythehvwenforcementcommunity.
Animaldispersedseedsandfruitsareubiquitous,ottenclingtenaciouslytoclothesorother
marerialswornorusedbysuspects,andaresmallandfrequentlygounnoticed.Further-
more,theiridentificationisrelativelyinexpensiveandtechnicallystraightforward,andtheir
presentationasevidenceisvisuallyandintuitivelyobvious,makingitidealforthecourt-
room.Itisalsosuggestedthatforensicbotanyisanexcellenttopictouseasacasestudyin
collegebotanyorbiologyclassesbecauseofitsinherentinterestandintegrativenature.In
ordertofacilitatesuchusage,abriefreviewofsomeaspectsofforensicbotanyispresented
includingreferencestopertinentliterature.
RESUMEN
Sepresentauncasoespecfficodepropagulosdiseminadosporanimalesenusoforense,y
sesugierequeestetipodeevidenciapuedetenetmayorutilizacionenvariosaspectosle-
gales.Lassemillasyfrutosdispersadosporanimalesestanportodaspartes,amenudose
enganchantenazmentealasropasuotrosmaterialesllcvadosousadosporsospechosos,y
porserpequefiospasanfrecuentementeinadvertidos.ademas,suidentificacionesrelativamente
barataytecnicamentesenciUa,ysupresentacioncomopruebaesobviavisualeintuitivamente,
convirtiendoseenidealparalosjuicios.Sesugieretambienquelabotanicaforenseesun
temaexcelenteparaserusadocomocasopracricoenlasclasesdebiologfaporsuinteres
inherenteynaturalezaintegrativa.Parafacilitareseusosehaceunabreverevisiondealgunos
aspectosdelabotanicaforenseincluycndolasreferenciasbibliograficaspertinentes.
Theuseofplantsinjusticeandlegalsystemsisthousandsofyearsold,
probably beginning in suchways as trials byordeal (Talalaj et al. 1991;
Mabberley1997).Inthesecases,suspectswereforcedtoeatpoisonousplants
andguiltorinnocencewasdetermined bysurvival. Presumably—,thiswas
basedonapsychological effectofguiltonthevomitingreflex suppos-
edly,innocentindividualswouldexpelthepoisonousmaterial,whilethe
SiDA18(1):335-346.1998
i.io SlDA18(1)
guilty would retain the poison and thus die; theefficacyofsuch atech-
niqueisobviouslyquestionable.Theuseofplantmaterialasevidencehas
alsoappearedinfictionalworks,suchastheseriesofbooksbyEllisPeters
aboutthemedievalWelshmonk/herbalist/sleuth,BrotherCadfael(Whiteman
1995)andtheworksbyH.C.Baileyaboutthedetective,ReginaldFortune
(Bailey 1936, 1943).
Themodernuseofplantsasevidenceinacotirtcasedatestothefamous
1930sLindberghkidnappingcasein whichthesonofCharlesandAnne
MorrowLmdberghwaskidnappedandmurdered.Largelythroughevidence
providedbybotanistArthurKoehler,BrunoHatiptmannwasconvictedof
thecrimein 1935.Koehlerdemonstratedthattheladderusedinthekid-
nappingwasbuiltinpartfromwoodtakenfromtheatticofHauptmann's
residence(Tippo&Stern 1977;Baden 1983;Haag 1983;Laneetal. 1990;
Graham1997).Koehler'sevidenceincludedidentificationofthewoodbased
onanatomicalcharacteristics,matchingofannualgrowthrings,andunique
markingsmadeonthewoodbytoolsincludingalumberyardplaneranda
handplane.Detailedaccotintsofthebotanicalevidenceincludingphoto-
graphsandgraphicscanbefoundinTippoandStern(1977),Haag(1983),
and Graham (1997). Graham (1997)gaveanextensivelistofreferences.
Thiswasalandmarkcase,notonlybecauseitleadtotheformationoffed-
eralkidnappinglaws(Bock&Norris 1997),butalsobecausetheobvious
valueoftheevidenceprovidedbyKoehlersetthestageforfutureforensic
usesofbotanicalinformation.
Sincethat time, therehavebeen numerousotherexampl—esofforensic
botany(andotherbiologicaldisciplinessuchasentomology e.g.,Rozen
and Eickwort 1997).The useofplantfragments,pollengrainsorfungal
spores,planttrichomes(hairs),anatomicalevidencefromindigestiblecell
wall material from thestomachcontentsofcrimevictims,molectilarevi-
denceutilizingDNA,andecologicalevidenceusefulinlocatinghiddengraves,
crimesites,ordatingwhenacrimeoccurredarejustafewexamples(Bock
etal. 1988;Laneetal. 1990;IMestel 1993;Yoon 1993;Blaney1995;Bates
etal. 1997;Bock&Norris1997;Graham1997;Lewis1997;Linden1997).
Thefollowingspecificcasesshowsomeofthediversityinthefieldofbo-
tanicalforensics. Laneetal. (199(^)discussed arapecase inwhichleaves
andbarkfragmentswerefoundinthepantscuffsofasuspect.Thematerial
had gotten intohiscuffswhilehewasclimbingatreetoirainaccesstoa
windowofthevictim's house. Hisclaim, that thevictim had lethim in
through adoor, did not match the botanicalevidence. Anotherexample
usedbyLaneetal.(1990)involvedachildabusecase.Theparentsclaimed
thatthechildhadbeenfedfruitcocktailjustpriortodying.However,their
storywascontradictedwhenhisstomachcontentsshowednoevidenceof
theanatomicallycharacteristicmaterialsexpectedfromsuchameal(e.g.,
LipscombandDicKis,Forensicbotany 337
stonecells frompearsorneedle-shapedcrystalsfrompineapples). In the
caseofa 1989planecrashnearRuidoso,NewMexico,itwasallegedthat
anenginedesignflawhadallowedparticulatematter(pollen)tobuildup
in theengineandcausethecrash. However, itwasshown thatsmce the
pollenwasinfreshconditionandhadnormalcytoplasmandcellwallsas
seen byelectronmicroscopy, itcouldnot havebeenexposed to thehigh
temperaturespresentduringengineoperationorinthepost-crashfirethat
distortedevenaluminum.Further,thepollenwasthatofinsect-pollinated
plantsfoundnearthestoragesiteoftheplanewreckage;suchpollengrains
areunlikelytobefoundinanyquantityintheatmosphere.Basedonthe
evidencefromforensicpalynology,itwasconcludedthatthepollenhadgotten
intothewreckagepost-crashduringseveralmonthsofstorageandthere-
forehadnothingtodowiththeaccident(Blaney1995;Brunk 1997;Gra-
ham 1997;Lewis 1997).Afinalexampleistheuseofmolecularevidence
linkingamurdersuspecttoapaloverdetree{ParkinsomaaadeataL.,Fabaceae)
atanArizonacrimesitewhereheallegedlydumpedthebodyofavictim.
PlantgeneticistTimHelentjarisoftheUniversityofArizonademonstrated
thattwoseedpodsfoundinthesuspect'struckcamefromaspecificpalo
verdetreescrapedbythesuspect'struckatthecrimescene.Thisexampleis
importantbecauseitwasthefirstinwhichplantDNAwasusedinacrimi-
nalcase(JMestel 1993;Yoon 1993).Overviewsofforensicbotanywerepro-
videdbyLaneetal.(1990) in thegeneral scienceliteratureandbyBock
andNorris(1997)intheforensicscienceliterature.
Ourinterestinthistopichasdevelopedoverthecourseofanumberof
yearsduringwhichasplanttaxonomistswehavebeencalleduponnumer-
oustimesbypoisoncenters,hospitals,andlawenforcementagenciestoidentify
plantsortheirfragments.WeagreewithBockandNorris(1997)thatfo-
rensicbotanyisaresourceunderutilizedbythelawenforcementcommu-
nity.Further,webelievethatforensicbotanycanbeveryeffectivelyusedin
botanyorbiologycoursestoshowtheimportance,applicability,andinte-
grativenatureofbotany.Becauseforensicbotanycutsacrossallbotanical
disciplinesandbecauseagivencasemayrequiremanyresearchapproaches
and techniques,itisadisciplinethatcanstresstheintegrativenatureof
botanyandscienceasawhole.Additionally,itisanexcellenttopictousein
emphasizingproblemsolvingandcriticalthinkingskills.Thepurposeof
thepresentarticleisthustwo-fold.First,basedonoursuccessfuluseofsuch
informationincollegeteaching,wewanttoprovideinaneasilyaccessible
botanical journalabriefreviewofforensic botanyandappropriaterefer-
encesinordertoencouragefurthersuchusage.Second,wepresentaspe-
cificcaseoftheforensicuseofanimal-dispersedpropagulesandsuggestthat
thistypeofevidencehasthepotentialtobemorewidelyusedincriminal
investigations.
3.^,8 SiDAlHd)
OnJuly12, 1995,asleepingtwoyearoldgirlwaspulledfromthefirst
floorwindowofanapartmentinFortWorth,Texas.Thechildwassexually
molested,butfortunatelywasfoundaliveaboutthreehourslaterinaweedy
areaseveralhundred metersfrom whereshewasabducted. Assortedevi-
dencewasused inthecaseincludingfingerprintsandDNAfromsemen.
However,theeasilyunderstandablebotanicalevidencewasanimportant
factorinconvincingthejuryofthesuspect'sguilt. BecausetheBotanical
ResearchInstituteofTexas(BRIT)isawellknownsourceofbotanicalin-
formationinthelocalcommunity,wewerecontactedbythedistrictattorney's
officetoidentifytinyplantfragmentstakenfromtheshoelacesofthesus-
pect.Inaddition,wewereprovidedwithabagofassortedplantmaterial
thathadbeencollectedfromthecrimescenewherethechildwasleft(Fig.
1). Uponopeningtheevidenceenvelope,weimmediatelyrecognized the
ca.4mmlongplantfragmentsassingle-seededmericarpsfromamember
oftheApiaceae(carrotfamily).Usingadissectingscopeandauthenticated
specimensintheBotanicalResearchInstituteofTexasherbarium,thesewere
identifiedasmericarpsoi'Tor/I/sarvensis(Huds.)Link,anintroducedspe-
ciescommonlyknownashedgeparsley.Thebagofmaterialfromthecrime
scenewasthenexaminedandamature,fruit-bearingplantofhedgepars-
leywasfound.Underadissectingscope,thesmallmericarpsofthisspecies
(Fig.2)areverydistinctive.Theyaredenselycoveredwithbristlestipped
withmicroscopicbarbsthatenhancetheirattachmenttofurorclothing.
Theyalsohaveseveralverycharacteristiclinesofcloselyappressedhairsbetween
thebristles.Largephotographsofmericarpsfromboththesuspect'sshoe-
lacesandthecrimescene(Fig.3)werepresentedincourtbyoneofus(BLL).
Likefingerprints,thiswasdistmctivevisualevidence,moreeasilyunder-
stoodthanthescientificallysoundbutconceptuallycomplexevidencepro-
videdbymoleculartechniquessuchasDNAanalysis.Becausethesuspect
couldhavepossiblypickedupthemericarpsfromsomeotherlocation,the
botanicalevidencealonewould nothavebeensufficientforaconviction.
However,itfirmlylinkedthesuspectwiththecrimesiteandincombina-
tion withotherevidence wassuccessfullyutilizedby prosecutorsSharon
McLauchlinandLarryThompsonandcriminalinvestigatorDennisTimmons.
Thesuspect,DavidNoelSaddlemire,wasconvictedofaggravatedkidnap-
pingwiththejurytakingonly55 minutestoreachtheirverdict(Fig.4).
Hewassubsequentlysentencedto99yearsintheTexasstateprisonsystem.
Ectozoochory,thetransportofadiasporeorpropaguleontheoutsideof
ananimal, isacommon mechanismofdispersalamongfloweringplants
(vanderPjil 1982).Whiletherearevarioustypesofdiaspores(e.g.,vegeta-
tive bulbils,fragmentsoftheparentplant), themostcommon typesare
seeds,wholefruits,orfruitsegments(e.g.,mericarpsas intheaboveex-
ample).Variousmethodsofattachmentareknown,rangingfromviscous
. . .
LipscombandDiggs,Forensicbotany 339
FORTWORTH POLICEDEPAflDlENT
CRIMEUBORATORI
RSCIIPT
CASl NO. 141868
TYFSr.i.SE Kidnapping/Sexual Assaulc Child
OFFKNSINO. 95 364266
VICTIM A. S.
SUSPSCT David Saddlemire
Raicc.iv.d fromt'l^(^/->0^^ L;p<.£r^^1^ ^'^.
DAT! "^• ^b TIMi IZ3^ AM FM ^^
DISCRIPTIONt
Received botanical evidence as listedbelow:
A tape sealedbrownpaper bagcontaining:
1 A(IItap-eIsnevaoliceedb#a9g5 Ch0o3l4d0i0n)gplant material
2. A tape sealed envelope holding:
A. A tape sealed envelopeholding plant
material collected fromright shoe
)?22 (Invoice ?/95C03410).
B. Atape sealed envelope holding plant
materialcollected fromleft shoe
#23 (Invoice #95C03410)
C. A tape sealed envelope holding a
subsample of plant material
(28 - Invoice #95C03471).
3. A tape sealedbag holding plantmaterial
(28 - Invoice //95C03471). < „ n
~^^ PRINT GtLjgi^Uion VQ^^Ctu
ISLEPHONlNO. <?/^ %1^ '6D^V
001-35506-025
8-1-77
Fig. 1.ReceiptofbotanicalevidencefromtheFortWorthPoliceDepartmentCrime
Laboratory.
340 SiDAlcS(l)
yy?
Fic.2.TorilisLini'iisis.A)habit;B)llower;C)iruitshowingmericarpswithiiiicinacebristles;
D)cross-SL'crionoffrLiir(drawnbyLinnyHeagy).
> >
LipscombandDiggs,Forensicbotany 341
Left Shoe Right Shoe
<—lcm~-> <—icm—
Known
— —
< 1cm
Fig.3.Photographsofmericarpsfrombotlithesuspect'sshoelacesandthecrimescene
(PhotosbyLarryA.Reynolds,courtesyofTarrantCountyMedicalExaminer).
ormucilaginoussubstances that cause thepropagule tosticktothedis-
persalagent,toverysharp,barbedorrecurvedhooks,spines,oravv'ns(van
derPjil1982).Webelievethatmanyoftheseexamplesarepotentiallyvaluable
tolawenforcementagencies.From manyfield tripsbothforresearchand
withstudents,ithasbeenourexperiencethatitisraretorettirnfromthe
fieldwithoutattachedplantmaterialeitheron theclothes,inpantcuffs,
onsocks, orembedded inshoelace—s. Someoftheseare merelyannoying,
whileothers{e.g.,Aristidaspecies threeawngrasses)areextremelyirri-
tatingwhenpenetratingsocksorpants.Manyoftheseseedsorfruitsfre-
quentlygettransferred totheinteriorofcarsoncarpetingorupholstery.
Onedoesnothavetogofarfromthesidewalktoencountersuchplantmaterials.
Becausemanyabundantweedyspeciesareanimal-dispersed,yards,aban-
donedlots,andvirtuallyanyweedyordisturbedsitewillhavesomesuch
species.Becatisetheseplantmaterialsaresofrequentlyencounteredandbecause
differentplantspeciesarefoundpredominantlyinspecifichabitatsandduring
particularseasons,theyarepotentiallyvaluablesourcesofevidencechatcan
linksuspectswithcrimescenesbothspatiallyandtemporally.Also,many
(e.g.,tinyfruitsegmentsofsomeApiaceaeortinyfruitsofsomegrasses)
342 SlDA18(1)
TARRANT COUNTY
OFFICEOFTHE
CRIMINALDISTRICTATTORNEY
TIMCURRY JUSTICECENTER
CRIMINALDI81S7T/R88I4C-T1400ATTORNEY FORTW40O1RTWH.,BETLSKN7A6P196.0201
Apnl21,1997
Mr.BarneyLipscomb
BotanicalResearchInstituteofTexas
509PecanStreet
FonWorth,Texas76102
DeariVIr.Lipscomb:
ThankyouforyourexpertiseandassistanceintheDavidSaddlemiretrial.Thecasewas
acomplexoneandyourtestimonywasveryhelpfulinexplainingtothejuryoneofthe
circumstancessurroundingtheoffense.
Thedefendantwasfoundguiltyandsentencedto99yearsinthepenitentiary.Again,
thankyouforyourassistance.ThiscasewasanimportantonetotheStateofTexasandthis
community.
n
.(j^-^^llciji2a^^d^
SharonMcLauchlin
AssistantCriminalDistnctAttorney
Fig.4.LetterIromTarrantCountyOlficeoftheCriminalDi.strictAttorneyconfirming
thejuryconvictionofDavidNoelSaddlemire.
becomedeeplyimbeddedinclothorcarpeting,govirtuallyunnoticed,and
oftenremainattachedevenafterrepeatedwashingsorothertypesofclean-
ing.Further,seedsandfruitsareeasilyandinexpensivelyidentifiedbytrained
botanistsusingnothingmorethanalOXhandlensorinexpensivedissect-
ingscope,taxonomicliterature,appropriateillustrations,andherbarium
specimens. Whilemolecularforensic techniques canpotentiallyprovide
verydefinitiveinformation,theyaremuchmoreexpensive,recjuiresophis-
ticatedlaboratoryfacilities,andarelessintuitivelyobviousforcourtroom
presentation.
LipscombandDiggs,Forensicbotany 343
Sometimes theattachmentofectozoochorouspropagulescan bequite
tenacious.Thismeansthattheycouldbeattachedtoaperpetrator'scloth-
ingforaverylongtime,orevenentertheflesh.Thefollowingarespecific
examplesfrommammalsthatillustratethepoint.Sharp-pointedstructures
suchasfruitsorawnscanpenetratethemouthorothertissuesoflivestock
(andhavetobeextractedbypliers)orevenbecomesubcutaneousandre-
quiresurgicalremoval.Veterinarians(JohnBrakebill,LarryEdwards,Ken
Lawrence,pers.comm.)indicatethatitisnotunco—mmontofindgrassburs
{Cenchrusspecies),awns(e.g.,fromHordeumspecies foxtail)orthepointed
fruitsofneedle,spear,orthreeawngrasses{NassellaorAristidcispecies)in
animals.Forexample,inNorthCentralTexas,Cenchrusbursareoftenfound
embeddedbetweenthetoesofdogsandgrassfruitsareknowntopenetrate
buccaltissuesincludingthetonguecausingseriousproblems(KenLawrence,
pers.comm.).Perhapsmorestrikingistheabilityofthesharpfruitsofneedle
grass(apparently,Nassellaleucotrkha(Tri—n.&Rupr.)Barkworth{formerly
knownasStipaleucotrkhaTrin.&Rupr.} commonlycalledwintergrass,
Texaswintergrass,speargrass,orTexasneedlegrass)todeeplypenetrate
flesh.Thesecanbecomesubcutaneousandrequiresurgicalremoval;forexample,
theycanenterbetweenthetoesofdogsandsometimesmigratelongdis-
tancessubcutaneouslycausingdrainingtractsthatwillnothealuntilthe
fruitisremoved(LarryEdwards,pers.comm.).Themostextremecasewe
areawareofinvolvedafruitthatpenetratedthroughtheskinandthenthe
chestwallofadog,eventuallybecomingembeddedinalungandcausing
afatalcaseofpneumonia(JohnBrakebill,pers.comm.).Alsotenaciousare
thespinyfruitsoiTribidusterrestrisL.,puncturevine,oftheZygophyllaceae.
Theseareverypainfultobothanimalandhumanfeet,damageeventires,
andareoccasionallyfaraltolivestockifeaten(Correll&Johnston1970);it
wouldnotbesurprisingtofindthemattachedtovariousobjectsandpos-
siblyeventhetiresofasuspect'svehicle.
LocallyinNorthCentralTexas,webelieveSolivapterosperma(Juss.)Less.,
lawnburweed,(Asteraceae)collectedfromasoccerfieldnearArlington,Tarrant
Co. (1995),waspossiblyspreadfromeasternTexasbyathleticshoes;its
fruitiseasily,andpainfully,attachedbyitspersistent,spine-likestyle(Diggs
etal.,forthcoming).Suchpropagulescouldremainattachedtoasuspect's
clothingorshoesforlongperiodsoftime.OtherAsteraceaearewell-known
asbeinganimal-dispersedwiththepappusofmanyspeciesbeingmodified
intoanattachmentstructure.TheretrorselybarbedawnsoiBidensspecies,
beggar'sticks,arestrikinglyeffective.Inanothercompositegenus,Xanthium,
cocklebur,thesurfaceoftheburisconspicuouslycoveredwithstiff,hooked
pricklesca. 5 mmlongandtheburisalsoterminatedbytwoprominent
spines.Theattachmentofthehookedpricklestoclothingorshoelacesis
344 SiDAlSd)
veryeffectiveandtheycanalsoeasilypenetratehumanskin.Thehooksare
strikinglyreminiscentofvelcro. AccordingtotheVELCRO® Industries
homepage(www.velcro.com),intheearly 1940s,aSwissinventor,George
deMestral,afterawalknoticed"cockleburrs"{presumablyX.anthiuvi\on
hisdogand hispants. Heexaminedthehookedpricklesunder—amicro-
scopeandderivedtheideaforthewellknowntwo-sidedfastener oneside
withstiff,cocklebur-like"hooks"andtheothersidewithsoft"loops"like
theclothofhispants.ThewordvelcrocomesfromtheFrenchwordsve-
lours,velvet,andcroche,hooked.
Whilesomeoftheexamplesabovewerepresentedtoshowthetenacity
withwhichdiasporesattach,commonly theseedsorfruitsaresmalland
merelyclingtothefur,feathers,feet,beak,etc.ofthedispersalagentwith
littleornoadverseeffect.Becausetheyareoftensmallandinconspicuous,
theymaybeparticularlyvaluablefromtheforensicstandpoint.Awellknown
suchmemberoftheFabaceae(legumefamily)isthegenusDesmodium,tickseeds.
Thefruitsorlomentsare jointedandbreakapart into 1-seeded flatseg-
mentsthatarethedispersalunits;theyeasilyattachtohairorclothing.In
NorthCentralTexasforexample, thereare 12 membersofthisgenus, a
numberofthemoccupyingratherspecifichabitats(Diggsetal.,forthcom-
ing).OtherwellknownexamplesarerhenumerousApiaceaethathavesmall
schizocarps(afruitthatsplitsbetweencarpelsintoone-seededportionscalled
mericarps)whosemericarpsarecoveredwithbristlesorhairsandbecome
readilyattachedtomanysurfaces.Theseareparticularlywellknowntoowners
oflong-ha—ireddogsbecauselargenumbersofthemericarpsbecomeentangled
inthefur sometimesthesituationissoseverethattheonlyrecourseisto
shavethedog.ThefinalexamplegivenhereisthelegumegenusMedicago,
commonlyknownasbur-clovers. Therearenumerousintroducedspecies
ofthisgenus,manyofwhichhavepricklyfruits.Thesefruitscanbesome-
whatlargerthanthosementionedpreviously, butarestilleffectiveatat-
tachingtodispersalagents.Numerousotherexamplescouldbegivenwhich
havepotential useforensically. Fortunately, mostareeasilyidentified by
experiencedfieldbotanistsbecausesuchresearchershaveencounteredthem
manytimesontheirownclothingorequipment.
Otherlessobviousdiasporescouldalsobepotentiallyuseful.Forexample,
atthepresenttime,severalinvasiveaquaticspecies(e.g.,Hydrillaverticillata
(L.f.)Royle,intheHydrocharitaceae)arespreadinginNorthCentralTexas,
apparentlybypowerboarstransportingvegetativepropagules(plantfrag-
ments). In areasofthecountrywheretherearenumerous relatively new
reservoirsandwherethedistributionsofmanyaquatics,especiallyintro-
ducedspecies,arespotty,plantmaterialofagivenspeciescouldeasilybe
usedinlinkingasuspectwithagivenbodyofwater.