Table Of ContentComp. Newsl.33, 1999 19
New chromosome comits for some Western
Australian Gnaphalieae (Compositae)
B.J. LEPSCHit*
WesternAustralianHerbarium
DepartmentofConservationandLandManagement
LockedBag 104
BentleyDeliveryCentre,WesternAustralia6983,Australia
and
G.J. Keighery
WesternAustralianWildlifeResearchCentre
DepartmentofConservationandLandManagement
PCBox51,Wanneroo,WesternAustralia6065,Australia
Abstract
ChromosomenumbersforOzothamnusramosus(n= 14),Pithocarpacorymbulosa,
P. pulchella (both n= 13), andRhodanthepsammophila (n = 5), arereported and
brieflydiscussed.
Introduction
TheGnaphaUeaeisamongthelargesttribesoftheCompositae,comprisingover180
generaand2000speciesdistributedthroughouttheworld(Bremer 1994).However,
unlikesomeothertribes oftheCompositae(e.g. Heliantheae), therehavebeen few
cytologicalstudiesdealingwithmembersoftheGnaphaheae(Turner 1977,Ander-
BERG 1991).
As part ofa study of the systematics ofthe genus Pithocarpa Lindl. by the first
author (Lepschi 1997), chromosome numbers of all diree taxa in that genus (see
Table 1) as well as in Ozothamnusramosus (DC.) PaulG.Wilson and Rhodanthe
psammophilaPaulG. Wilson weredetermined. This paperpresentschromosome
countsforthesetaxa,noneofwhichappeartohavebeenpreviouslyrecorded, apart
t)Presentaddress:AustralianNationalHerbarium,CentreforPlantBiodiversityResearch,
GBPBox 1600,Canberra,ACT,2601Australia
*)Authorforcorrespondence.
20 Comp.Newsl.33, 1999
from R. psammophila (see under Helipterum condensatum F. Muell., in Turner
1970).ItshouldbenotedthatO. ramosus doesnotbelongtoOzothamnussens,str.,
and will be transferred to a new genus along with a handful of other Australian
speciescurrentlyplacedin Ozothamnus(C.F. Puttockpers.comm.).
MaterialsandMethods
Young,freshlycollectedbudswereplacedinasolutionof4partschloroform,3parts
95% alcohol and 1 part acetic acid. These were subsequently transferred to an
acetocarmine stain, with meiotic material then examined after"squashing" pollen
mothercells.Countsweremadeusingabinocularcompoundmicroscopewithanoil
immersionachromaticlensgivingamagnificationofapproximatelyxlOOO,withup
tofivecountsmadepercollection.Allbudmaterialwascollectedfi-omwildplantsin
thefield,exceptforR.psammophila, forwhichmaterialwascollectedfromplantsin
cultivation.VouchersforallcountsaredepositedatPERTH.
ResultsandDiscussion
Results obtained from this study are presented in Table 1. Taxa are arranged
alphabetically.
Table 1.ChromosomenumbersinsomeWesternAustralianGnaphaheae.
Taxon
Comp.Newsl.33, 1999 21
The paucity ofcytological studies on the Gnaphalieae unfortunately limits what
inferences can be drawn from the data presented here. However, some general
observationscanbemade. Solbrigetal. (1964) andSolbrig(1977)notethatinthe
Compositae, perennial species generally have higher chromosome numbers (i.e.
greaterthan n=9)whileannualspecies,particularlythosefromaridareas,tendto
havelowerchromosomenumbers.OurdataagreeswiththatofSolbrigetal.(1964)
and Solbrig (1977), with O. ramosus (n = 14) andPithocarpa spp. (n = 13) being
perennial species from the relatively mesic south-west ofWestern AusU-alia, and
with R. psammophila {n = 5) being an annual species restricted to the Carnarvon
districtineremeanWesternAustraUa.
Breedingsystemsandchromosomenumbersmayalsoshowsomecorrelation, with
higherchromosome numbers (i.e. greater than n = 9), often found in outbreeding
taxain the Compositae (Solbrig 1977). Studies by the first author (Lepschi 1997),
suggestthatallPithocarpaspp.areoutbreeders,andthecorrespondingchromosome
number ofn = 13 for all taxa in the genus is consistent with this. The breeding
systemsoftheothertaxaincludedinthisstudy haveyettobedetermined.
Directcomparisonofchromosomecountsobtainedfortaxainthisstudy withthose
ofrelated species is unfortunately not possible for most taxa. The only published
chromosome counts for species of Ozothamnus are those reported in Hair &
Beuzenberg (1968) for seven New Zealand species (as Helichrysum spp.), all of
which are n = 14. However, as mentioned above, O. ramosus does not belong in
Ozothamnussens, str., andcomparison ofchromosome numbers in this taxon and
theNewZealandspecieswouldnotbeparticularly meaningful atthis stage,except
forrelationships atthegeneric level. Furthertaxonomicandcytological studies on
Ozothamnusareurgentlyrequired.
Thecountofn=5 obtainedforR.psammophilaconfirmsthatreportedbyTurner
(1970;asHelipterumcondensatum).RhodantheLindl.,aspresentlycircumscribed,
is a heterogeneous assemblage (Anderberg 1991, P. G. Wilson pers. comm.) the
members of which exhibit great variation in chromosome numbers. As with
Ozothamnus, further systematic and cytological studies are needed to clarify the
significance ofthis variation. Therelationships ofPithocarpa arenotclear, butthe
resultsofarecentphylogeneticstudy ofPithocarpa(Lepschi 1997), suggestthatits
closest affinities may be with taxa ofthe 'Lawrencella complex' ofgenera (sensu
Anderberg 1991).However,Lepschi(1997)studiedonlyaselectionofthepotential
relativesofPithocarpa(includingArgentipalliumniveum (Steetz)PaulG.Welson
and O. ramosus oftheL<zwrence//acomplex),andamore comprehensivesamphng
oftaxa would be required to accurately determine the sister taxon to Pithocarpa.
22 Comp.Newsl.33, 1999
Data on chromosome numbers in genera ofthe Lawrencella complex is poor, but
chromosome numbers ofn = 8, 11 and c. 24 have been reported (Turner 1970).
Anderberg(1991)alsorecords«= 14,butthisappearstobeinerror.Argentipallium
niveum, which appears as the sistertaxon to Pithocarpa in the analysis ofLepschi
(1997)hasachromosomenumberof«=c.24(Turner1970;asHelipterumobtusifo-
liumSoND.).
Acknowledgements
Theauthors aregratefultoDaveCoatesandVickiHamleyforlaboratoryfacilities,
and BJLwishestothankTerenaLallyforassistancewithfieldwork.
References
Anderberg, A. A. 1991. Taxonomy and phylogeny of the tribe Gnaphalieae
(Asteraceae). OperaBot. 104: 1-195.
Bremer, K. 1994. Asteraceae: Cladisticsand Classification. TimberPress, Port-
land,Oregon.
Hair,J. B. & E.J. Beuzenberg 1968. Contributionstoachromosome atlas ofthe
New Zealand flora 2. Miscellaneous families. New Zealand J. Bot.
6: 19-24.
Lepschi,B.J. 1997. AtaxonomicrevisionofPithocarpa(Gnaphalieae:Asteraceae)
and an assessment ofits phylogeny. Unpublished Postgraduate Diploma
thesis, CurtinUniversityofTechnology,AustraUa.
SoLBRiG,O.T. 1977.ChromosomecytologyandevolutioninthefamilyCompositae.
In: Heywood,V. H., Harborne, B. J. &B. L.Turner(eds.), TheBiologyand
Chemistryofthe Compositae, 1.AcademicPress,London, pp. 246-260.
Solbrig, O. T.,Anderson, L. C, Kyhos, D. W., Raven, R H. & L. Rudenberg
1964. Chromosome numbers in Compositae V. Asterae U. Amer J. Bot.
51:513-519.
Turner, B. L. 1970. Chromosome numbers in Compositae 12.Australian species.
Amen J. Bot. 57: 382-389.
Turner,B.L. 1977. Sununaryofthebiology oftheCompositae.In: Heywood,V.
H.,Harborne, B. J. &B. L. Turner(eds.). TheBiologyandChemistryofthe
Compositae, 2. AcademicPress,London,pp. 1105-1119.
