Chromosome Numbers of Hawaiian Angiosperms

16 Pages·2005·0.11 MB·English

Chromosome Numbers of Hawaiian Angiosperms:
New Records and Comments1
Michael Kiehn2
Abstract: In this paper chromosome counts for 90 collections representing
67 native Hawaiian angiosperm species and eight hybrids in 22 families are
presented and discussed. Included are the first records for 26 species, two sub-
specific taxa, eight natural hybrids, and the endemic genus Pteralyxia (Apocyna-
ceae). In four families Hawaiian representatives have been investigated
cytologically for the first time. For three species the investigations are the first
on Hawaiian material. Seven counts differ from earlier reports in the literature.
Implications of the results are discussed in the context of autochthonous chro-
mosomalevolutionand ofcolonization events for the Hawaiian Islands.
Chromosome numbers are available for growing root tips, shoot apices, or young
nearly 40% of the native Hawaiian species flowers for mitotic counts, or young flower
(Carr 1998). In most cases these numbers buds for meiotic investigations of plants cul-
were obtained from counts of single or very tivated at the National Tropical Botanical
few individuals. In this paper it is aimed Garden, La¯wa‘i, Kaua‘i, Hawai‘i (NTBG),
to improve the knowledge on chromosome andof plants collected in the wild were made
numbers for Hawaiian angiosperms, both in a freshly mixed 3:1 solution of ethanol
with regard to taxa not previously investi- (96%):glacial acetic acid. In each field fixa-
gated and for additional collections of taxa tion, only one individual was sampled (except
already counted. Data for 19 species pre- for Labordia degeneri, DL6453, collected and
sented here were shared with G. Carr (Uni- fixedbyD.Lorence,whereseveralindividuals
versity of Hawai‘i at Ma¯noa, Honolulu) and may have been sampled in the same fixation).
were included in his earlier survey (Carr Additional fixations of root tips were taken
1998, table 1.1) as ‘‘Kiehn unpubl.’’ These fromplantscultivatedattheBotanicalGarden
counts are documented and discussed further of the University of Vienna, Austria (HBV),
here andare footnoted ‘‘c’’ inTable 1. from seeds collected in Hawai‘i; the root
tips were pretreated in 8-hydroxyquinoline
materials and methods (0.002 m, ca. 6 hr at 8–10(cid:1)C). Each root
tip fixation represented one individual. The
In the course of eight visits to Hawai‘i be- fixed material was stored at 8–10(cid:1)C before
tween 1989 and 2003, fixations of actively
staining with Giemsa (after hydrolysis in 5 N
HCl for 50 min. at 20(cid:1)C) or with Feulgen
(Kiehn 1995). Hot aceto-carmine (2% solu-
1Partsofthisstudyweresupportedfinanciallybythe
tion in 45% acetic acid) was used to intensify
Austrian Science Foundation (FWF-proj. P-13107-Bio),
theO¨sterr.Forschungsgemeinschaft(proj.06/3699),the staining if needed. Somatic chromosome
Hochschuljubila¨umsstiftung der Stadt Wien (proj. Nr. numbers (2n) were established from any of
H-21/94), and the National Tropical Botanical Garden, several tissue sources, including premeiotic
La¯wa‘i,Kaua‘i,Hawai‘i.Manuscriptaccepted20 August
anthers, young flower buds, young ovaries,
2004.
2InstituteofBotany,UniversityofVienna,Rennweg ovary wall, and root tips. Gametic number
14, A-1030 Vienna, Austria (e-mail: michael.kiehn@ determinations (n) werederivedfrom meiotic
univie.ac.at). divisions of microsporocytes. Collection data
for each studied sample are listed in Table
1. Voucher specimens have been deposited
PacificScience(2005),vol.59,no.3:363–377
:2005byUniversityofHawai‘iPress in the herbaria at the University of Vienna
Allrightsreserved (wu),attheNationalTropicalBotanicalGar-
363
.
364 PACIFIC SCIENCE July2005
den (ptbg), and/or in other herbaria as stated dra have been counted so far; both are tetra-
in Table 1. Permanent slides for most of the ploidswithn¼24=2n¼48(Carr1978,1998,
counts are in the collection ofthe author. Kiehn and Lorence 1996). The data reported
here for Tetraplasandra bisattenuata (2n¼46–
48) fit well into the picture for this group.
results
campanulaceae:Thechromosomenum-
Chromosome counts for 67 species (90 ber determinations for seven species, five
collections) of native Hawaiian angiosperms of which are new counts, are in accor-
from 22 families are presented in Table dance with the earlier data for Hawaiian
1. They include the first chromosome num- species summarized by Lammers (1988)
ber reports for 26 species, two subspecific and Carr (1998). All Hawaiian taxa of the
taxa, eight natural hybrids, and the endemic family cytologically investigated to date ex-
genus Pteralyxia (Apocynaceae). In four fami- hibit 2n¼28; Carr (1998) considered single
lies (Droseraceae, Myrsinaceae, Orchidaceae, deviatingreportstobeerroneous,aviewcor-
andViscaceae)Hawaiian representativeshave roboratedbythe results presented here.
been investigated cytologically for the first caryophyllaceae: Of the seven Hawai-
time. For three indigenous Hawaiian species ianspeciesofSilene,S.alexanderifromMolo-
theinvestigationsarethefirstonesonHawai- ka‘i reported here is the third to be counted
ian material. Counts for seven species differ (see Carr 1998). All three species exhibit
from earlier reports; 18 counts are in accor- 2n¼24,inagreementwithx¼12asthepre-
dancewithearlierpublisheddata.Somechro- dominant basic number for Silene (cf., e.g.,
mosome numbers are reported as a range. GoldblattandJohnson2000).
This is the case in taxa with high chromo- cyperaceae: The chromosome number
some numbers (e.g., in Hedyotis spp. or Cop- for Eleocharis obtusa is established for the
rosma ernodeoides) where different counts on first time on Hawaiian material. The result
several individuals led to differing results, or of 2n¼10 is in accordance with earlier
wascausedbychromosomesstickingtogether counts for this species (e.g., from northeast-
duringfixation(e.g.,inAlyxia,Labordia,Lipa- ernAmerica[Gervais and Cayouette 1985]).
ris, or Korthalsella). droseraceae: The first count for Dro-
seraanglicaonmaterialfromHawai‘irevealed
2n¼40. This result is in accordance with
discussion
earlier reports for this, by Murı´n and Ma´jov-
sky´ (1987) from Europe and by Kondo
Discussionof the new data in a taxonomic
and Segawa (1988) from Asia. Thus there is
context
no apparent variation in the chromosome
apocynaceae: The results reported number of this species across its whole range
here for Alyxia stellata (¼A. oliviformis, cf. of distribution. In contrast, the genus Drosera
Middleton 2000) and for Pteralyxia kauaiensis in general is extremely variable in basic num-
(firstcountforthegenus)areinlinewithpre- bers (ranging from x¼3to x¼9, with addi-
viousreportsforthegenusAlyxia(Skottsberg tional reports of x¼13 and x¼15 [Kondo
1955: 2n¼ca. 36, 2n¼ca. 39 for A. stellata; and Lavarack 1984, Kondo and Segawa
Van der Laan and Arends 1985: 2n¼36 for 1988,SheikhandKondo1995])andinploidy
two non-Hawaiian Alyxia species). The re- levels (from diploidyto dodecaploidy [Kondo
ported range of 2n¼34–36 is caused by the and Lavarack 1984, Sheikh and Kondo
relatively large chromosomes being twisted 1995]).
around each other inthe available fixations. ericaceae: Two of the three native Ha-
araliaceae: Accordingtomoleculardata, waiian Vaccinium species (V. calycinum, V. re-
the Hawaiian genera Munroidendron, Reynold- ticulatum) have already been counted; both
sia, and Tetraplasandra are closely related to exhibit 2n¼24 (Carr 1998). The result of
eachother(Wenetal.2001).Themonotypic 2n¼48 obtained here for Vaccinium cf. den-
MunroidendronandonespeciesofTetraplasan- tatum from Moloka‘i indicates the presence
.
ChromosomeNumbersofHawaiianAngiosperms Kiehn 365
of tetraploidy in Hawaiian representatives of reports by Borgmann 1964 for taxa from
the genus. New Guinea [see Kiehn and Weber 1998 for
The three native Hawaiian Vaccinium discussion]).Thegenusprovestobeveryuni-
species, together with the southern Polyne- form karyologically. Some variation in chro-
sianspeciesV.cereum,formthemonophyletic mosome length and size (as discussed by
sect. Macropelma of Vaccinium (Vander Kloet Storey 1966) can be seen in Hawaiian mate-
1996). Vander Kloet (1996) hypothesized rial, but this is (at least partly) caused by
that the Hawaiian taxa compose a coherent differences in fixation and pretreatments, be-
evolutionary unit of occasionally anastomos- cause such variation was also observed in dif-
ing selfing lineages. The production of such ferent fixations of the same taxon (e.g., of C.
hybrid lineages could explain the presence of hawaiensis andof C. paludosa).
two ploidy levels among the Hawaiian taxa. Ranges of numbers given for C. grayi, C.
Thedifficultiesinidentifyingtheinvestigated kalihii, C. lessoniana, and C. platyphylla are
VacciniumcollectionfromMoloka‘icouldalso due to the poor quality of the respective fixa-
be due to a hybrid origin of the investigated tions and most probably do not reflect a real
collection.Itwouldbedesirabletostudymei- range of chromosome numbers in these spe-
otic divisions in this group or to use molecu- cies.InthecaseoftheC.lessonianacollection,
lar fingerprint methods to further evaluate this assumption is supported by the obser-
the hypothesis ofVander Kloet (1996). vation of regular meiotic divisions. Regular
geraniaceae: The genus Geranium is meiotic divisions are also present in collec-
represented in Hawai‘i by six native species. tionsofC.hawaiensis,C.kauaiensis,C.paludosa
The chromosome number established here var. paludosa, C. sandwicensis, and in two puta-
for Geranium cuneatum subsp. tridens from tive hybrids. However, meiotic irregularities
East Maui (2n¼48–52) is in the same range were found in the investigated material of C.
as the only earlier report available for a grandifloraandC.munroi.Inspiteofcytoplas-
Hawaiian species (G. arboreum: 2n¼ca. 50 mic bridges and the presence of abnormal
[Carr1978,1998])andsimilartofourreports pollen grains, C. grandiflora clearly revealed
for New Zealand species ranging from n¼17 in regular divisions. However, the
2n¼52to2n¼56(DawsonandBeuzenberg range given for C. munroi could reflect true
2000). A survey of chromosome counts for variation. Collection MK-990913-3/2 of this
Geranium (http://www.rjb.csic.es/Geranium/ species exhibited meiotic irregularities, in-
index_geranium.html) reports basic num- cluding anaphase bridges, lagging univalents,
bers for the genus as x¼n¼9, 10, 11, 12, cytoplasmic bridges between pollen mother
13,14,15,16,17,21?,23,25,withapredom- cells (PMCs), anda high frequency ofabnor-
inance of x¼14. Although chromosome mal pollen.
morphology and numbers proved very useful All investigated (putative) hybrids and
for the systematic treatment of the related their (hypothetical) parents are on the same
genus Pelargonium (Gibby et al. 1996), there ploidy level and have the same chromosome
arenopublishedstudiesrelatingthechromo- numbers. Only one of the eight hybrids ana-
some data of Geranium to a comprehensive lyzed showed meiotic irregularities (hybrid II
taxonomic treatment ofthe genus. from Maui had degenerated pollen). Pollen
gesneriaceae: Counts are now available viabilitytestedbyLuegmayr(1993)for16ac-
for 24 of the 58 Hawaiian species of Cyrtan- cessions of 12 different interspecific hybrids
dra and for eight naturally occurring hybrids of Hawaiian Cyrtandra was between 70 and
(Table 1 and Storey 1966). The counts cover 99% for 15 of those accessions. Only one ac-
all sections of the genus in Hawai‘i as recog- cession showed a very low viability (of 2%).
nized by Wagner et al.(1999). Germination rates of seeds from six inter-
All collections that allowed an exact count specific hybrids were all approximately 90%,
revealed a chromosome number of n¼17 similartothoseoftruespecies(unpubl.data).
or 2n¼34, as did all other Cyrtandra species Thus,itcanbeassumedthatmostnaturalhy-
counted so far (with the exception of three bridsbetweenHawaiianCyrtandraspeciesare
u), u) u)
ms aIsland,Voucher(Herbarium) bish,wuO‘ahu,()Kiehn&ImadaMK-940911-2/3ptbgw¼Kaua‘i,()(Wood7701KiehnMK-031224-5NTBGcult.#990087 ptbgKaua‘i,()LorenceDL8404 wuMaui,()Kiehnetal.MK-990914-1/1 wuKaua‘i,()Kiehnetal.MK-920831-1/8bishMoloka‘i,()KiehnMK-940901-2/4wuHawai‘i,()Kiehn&CuddihyMK-920818-1/2aptbgKaua‘i,()Woods1352wuKaua‘i,()Kiehn&FlynnMK-900906-1/13ll,wuKaua‘i,()Kiehn&LuegmayrMK-920831-1/3 wuMoloka‘i,()Kiehnetal.MK-920816-5/1 w¼Kaua‘i,(LorenceDL8433KiehnMK-990911-4/1 w¼Kaua‘i,(LorenceDL8429KiehnMK-990911-2/1 wuMoloka‘i,()Kiehnetal.MK-920817-2/3 wuMaui,()Kiehnetal.MK-920822-2/1 bish,wuO‘ahu,()Kiehn&ObataMK-890809-2/6wuKaua‘i,()Kiehn&KiehnMK-890802-1/1wuO‘ahu,()Kiehnetal.MK-900822-1/1bish,wuO‘ahu,()Takahamaetal.MK-990901-3/1wuO‘ahu,()Takahamaetal.MK-990901-5/1ptbg,wuO‘ahu,()Kiehnetal.MK-900722-1/1bish,wuMaui,()Kiehnetal.MK-890723-2/2srpMaui,()Smith3915
r
e
p
os
gi
n
waiianA SomaticNumber(2)n 34–3634–36 46–48 28 282828282828 24 10 40 b48 b48–52 c34c34c343434—c34c34
1 a
E H
BL of
A rs
T eNumbe GameticNumber()n —— — — —————— — — — — — —————c,d17——
m
o
os
m
o
r
h
C
ult.
Taxon Apocynaceae(J.R.Forst.&G.Forst.)Roem.&SchAlyxiastellataþþþþCaumPteralyxiakauaiensis AraliaceaeþþþSherffTetraplasandrabisattenuataCampanulaceaeþþþ(H.Mann)Hillebr.subsp.Clermontiaarborescens(Wawra)Lammerswaihiaeþþþ´H.Lev.C.faurieiþþþHillebr.C.pallidaGaud.exA.GrayC.parvifloraþþþSt.JohnCyaneaasarifoliaþþþ´H.Lev.C.fauriei(Rock)Skottsb.TrematolobeliakauaiensisCaryophyllaceaeþþþHillebr.SilenealexanderiCyperaceaeþ(Willd.)Schult.Eleocharisobtusa#DroseraceaeþHuds.DroseraanglicaEricaceaeþþþcf.Sm.VacciniumdentatumGeraniaceaeþþþHook.subsp.(Hillebr.)GeraniumcuneatumtridensCarlq.&BissingGesneriaceae(Rock)St.John&StoreyCyrtandracalpidicarpa(Wawra)C.B.Clarkevar.C.confertifloraconfertifloraGaud.C.cordifoliaþþþSt.John&StoreyC.dentata Gaud.C.grandifloraHillebr.C.grayana
u) u)
bish,wuMaui,()Kiehnetal.MK-990913-1/1wuMaui,()Kiehnetal.MK-900803-3/3wuMaui,()Kiehnetal.MK-990914-1/6bish,ptbg,wO‘ahu,(Kiehn&ObataMK-890809-1/2bish,wuO‘ahu,()Kiehn&ObataMK-890809-1/3bish,wuO‘ahu,()Kiehn&ObataMK-890809-1/5bishO‘ahu,()Kiehn&ObataMK-890809-1/7bishO‘ahu,()Kiehn&ObataMK-890809-2/2wuO‘ahu,()Takahamaetal.MK-990902-4/1ptbg,wuKaua‘i,()Kiehnetal.MK-900724-6/1wuKaua‘i,()MK-920825-3/3bishO‘ahu,()Kiehn&ObataMK-890809-1/4bish,ptbgO‘ahu,()Kiehn&ObataMK-890809-1/6ptbgO‘ahu,()Takahamaetal.MK-990902-2/6wuO‘ahu,()Takahamaetal.MK-990902-2/6abish,ptbg,wKaua‘i,(Kiehn&KiehnMK-890720-1/1us,wuHawai‘i,()Kiehn&CuddihyMK-900812-2/3wuMaui,()Kiehnetal.MK-990913-3/2bish,wuMaui,()Kiehnetal.MK-990913-4/1ptbgKaua‘i,()Kiehnetal.MK-900823-1/3ptbg,us,wuKaua‘i,()Kiehnetal.MK-900823-2/11usKaua‘i,()Kiehnetal.MK-900823-1/13us,wuMaui,()Kiehnetal.MK-900803-7/3wuMaui,()Kiehnetal.MK-990914-1/7wuMaui,()Kiehnetal.MK-990914-1/9abish,ll,us,wuO‘ahu,()Kiehnetal.MK-920909-3/2bish,ptbg,wuO‘ahu,()Kiehnetal.MK-900722-2/1wuMaui,()Kiehnetal.MK-920823-1/1 bish,wuO‘ahu,()Kiehn&ObataMK-890809-2/4bish,wuO‘ahu,()Kiehn&ObataMK-890809-2/3bish,wuO‘ahu,()Kiehn&ObataMK-890809-1/1wuHawai‘i,()Kiehnetal.MK-920819-1/1us,wuMaui,()Kiehnetal.MK-900803-7/2wuKaua‘i,()Kiehn&LuegmayrMK-920825-3/2wuMaui,()Kiehnetal.MK-990914-1/9wuMaui,()Kiehnetal.MK-990914-1/10
6 4 44 6 e4
3 3 33 3 3
4–c4c4c4c4c4c4c42–c4c4c4c42–2–c4c444c44c4c4c44–4c44 444—44—2–
3333333333333333333333333333 333 33 3
es)
u
n
nti
o
c
(
7 d7 c7
1 1 1
———c7—————c7 ———6–——5–———6–————c7— ———7——7—
1 1 1 1 1 1 1 1
e
k
þþþC.B.ClarkeC.grayiRockC.hashimotoi C.B.ClarkeC.hawaiensis þþþWawraC.kalihiiWawraC.kauaiensis St.John&StoreyC.kaulanthaH.MannC.laxifloraþþþGaud.C.lessoniana (Wawra)Hillebr.exC.B.ClarC.longifolia(A.Gray)C.B.ClarkeC.lysiosepalaþþþC.ForbesC.munroi H.MannC.oenobarbaþþGaud.var.WawraC.paludosamicrocarpaGaud.var.C.paludosapaludosa þþþA.GrayC.platyphyllaC.ForbesC.propinqua`(H.Lev.)St.John&StoreyC.sandwicensisþþþSt.JohnC.spathulatahybrids:Cyrtandraþþ(cid:2)C.cordifoliaC.propinquaþþ(cid:2)C.hawaiensisC.calpidicarpaþþ(cid:2)cf.C.hawaiensisC.laxifloraþþ(cid:2)C.hawaiensisC.menziesiiþþ(cid:2)var.C.hashimotoiC.paludosapaludosaþþ(cid:2)var.C.kauaiensisC.longifloralongifloraþþhybrid5C.þþhybridIIC.
u)
aIsland,Voucher(Herbarium) ptbgKaua‘i,()LorenceDL6453wu¼Kaua‘i,()Flynn6633KiehnMK-990910-3/7ptbgKaua‘i,()LorenceDL6364&6365w¼Kaua‘i,(LorenceDL8432KiehnMK-990911-3/3wuO‘ahu,()Takahamaetal.MK-990902-2/7 bish,wuMaui,()Kiehnetal.MK-990914-1/2 wuO‘ahu,()Takahamaetal.MK-990901-2/1a wuMaui,()Kiehnetal.MK-990913-3/4 wuO‘ahu,()Takahamaetal.MK-990901-2/1wuMaui,()Kiehnetal.MK-990914-1/3wu¼Kaua‘i,()Flynn6622KiehnMK-990910-2/3 wuKaua‘i,()Kiehnetal.MK-900823-2/8ny,ptbg,usKaua‘i,()Wood2388ny,ptbgO‘ahu,()Perlman15594 ptbgKaua‘i,()Flynn3401mo,ptbgKaua‘i,()Perlmanetal.13334 wu¼Kaua‘i,()Flynn6625aKiehnMK-990910-2/1a wuHawai‘i,()KiehnMK-900814-5/1wuMaui,()Kiehnetal.MK-890723-1/2bish,wuO‘ahu,()Takahamaetal.MK-990902-2/3bish,wuO‘ahu,()Takahamaetal.MK-990902-5/1bish,ptbg,usLana‘i,()Lorence8850¯wuKaua‘i,()KiehnMK-890720-1/2bish,wu,ptbgKaua‘i,()Kiehnetal.MK-890804-2/1bishO‘ahu,()Kiehnetal.MK-940910-3/1
c0 b
ntinued) SomaticNumber(2)n ><406b58–62c40–44b59–61bc.60 46 44(–46) 26–30 32–3632–3624 c24c24b24 —42–44 72 254–2644440–44ca.10094–10090–100c66–8866
o
c
(
1
E
L
TAB GameticNumber()n ———b30–34 — — — ——— ——— 18–20— — ————————
b.
Rocka Schult. ebr.)FosHerbst
Taxon LoganiaceaeSherffLabordiadegeneri SherffL.helleriWawraL.waialealaeWawraL.waiolani#MyrsinaceaeþþþA.DC.MyrsinesandwicensisOleaceae(A.Gray)Degener&al.Nestegissandwicensis#OrchidaceaeþþþH.MannLiparishawaiensisPittosporaceaesp.IPittosporumsp.IIP.þþþRockP.gayanumPlantaginaceaeCham.&Schlechtd.var.Plantagoprincepsanomal Cham.&Schlechtd.var.P.princepsprincepsPoaceaeþ(L.)P.Beauv.exRoem.&Heteropogoncontortusþþþ(Reichart)Hitchc.PoasandvicensisPrimulaceaeRockLysimachiaglutinosaRubiaceaeA.GrayCoprosmaernodeoidesA.GrayC.foliosaW.OliverC.ochracea(Hook.&Arn.)Steud.HedyotiscentrantoidesþþþSteud.subsp.(HillH.schlechtendahlianaremyi(Hook.&Arn.)W.L.Wagner&H.terminalisFosb.Psychotriagreenwelliae(Cham.&Schltd.)Fosb.P.mariniana
u) he
w t
y, for
n d
canb,(6u)wu()4 wu()4 wu()3 firstrecor
910-3/w(2/2910-3/ 910-2/ 910-3/ þbrid;,
¼Kaua‘i,Flynn6632KiehnMK-990O‘ahu,Takahamaetal.MK-990902-¼Kaua‘i,Flynn6630KiehnMK-990 ¼Kaua‘i,Flynn6623KiehnMK-990 ptbgHawai‘i,()Perlman13048 ¼Kaua‘i,Flynn6629KiehnMK-990 firstrecordforthesubspecies,variety,orhy
þ,
þ
es;
ci
e
g p
f,36 b–26 –32 thes
363618 24 16 28 for
d
or
c
e
r
b first
3) þ,
1 6 þ
(cid:3) 1 þ
——— 2( — 4– us;
1 1 n
e
g
e
h
t
or
f
d
or
c
e
r
r first
gene þþþþ,
RutaceaeþþþA.GrayMelicopebarbigerasp.IM.sp.IIM.Sapotaceae(A.Gray)Baehni&DePouteriasandwicensisViolaceaeþþþA.GrayIsodendrionpyrifolium#Viscaceaeþþþcf.(Tiegh.)Engl.Korthalsellaplatycaula #,FirstreportforthefamilyfromHawai‘i;Note:taxonfromHawai‘i.aAbbreviationsfollowHolmgrenetal.(1990).bNumberdiffersfromearlierliteraturereports.cReportedas‘‘Kiehnunpubl.’’inCarr(1998).dMeioticirregularitiesobserved(seetext).ePollendegenerated.fBasedononeseedling.gBasedonthreeseedlings.
.
370 PACIFIC SCIENCE July2005
fully fertile. Of particular interest in this re- (1998). In the light of the divergent data for
gard is Smith 2874, a collection of Cyrtandra L. helleri andthe low number of counts avail-
from O‘ahu that has been independently able, Carr (1998:32) stated that ‘‘additional
identifiedasanF hybridbetweenC.cordifolia clarification and confirmation of the lower
1
and C. laxiflora by W. L. Wagner (Smithso- numbers determined by Kiehn (unpublished)
nian Institution) and myself. A seedling from ... would strengthen the case of autochtho-
a fruit of this hybrid regularly sets flowers at nous polyploidy in Labordia.’’
the Botanical Garden, University of Vienna. New data provided here give further
Morphologically, this plant cannot be distin- evidence for the existence of different ploidy
guishedfromoneoftheparentsoftheF hy- levels in the genus: besides tetraploidy and
1
brid, C. laxiflora. More work on hybrids (in octoploidy(alreadyrevealedbyearliercounts)
particular with larger numbers of plants) is hexaploidy could be present in L. degeneri, L.
desirabletofurtherinterpretthisobservation. waialealae,andL.waiolani.Thesenew results,
One explanation could be that species differ- however, also raise questions because there
ences are based on only a few genes, and are now three species of Labordia (L. helleri,
backcrosses of an F hybrid with one of the L. waialealae, L. waiolani) for which two dif-
1
parental species yield progeny very similar to ferent ploidy levels are reported. The result
therecurrentparentalspecies.Thiswouldex- of 2n>40<60 for L. degeneri (Kiehn in
plain the observation of individual F hybrid Carr 1998) may indicate another instance
1
plantsbetweensympatricallygrowingCyrtan- of infraspecific polyploidy in Labordia. The
dra species and the apparent lack of ‘‘hybrid range reported was due to the fact that
swarms’’inCyrtandrainHawai‘i.Carr(1995) the field fixation, Lorence DL6453, contained
discussed the potential relevance of hybrid- some cells with 2n¼ca. 40 and others with
ization to plant evolution in the Hawaiian Is- 2n¼ca. 60 chromosomes, possibly because
lands based on an example in the Asteraceae- individuals at different ploidy levels were
Madiinae. sampled in this fixation (this is the only fixa-
loganiaceae (geniostomaceae): Re- tion where the number of collected individ-
cent molecular work (Struwe et al. 1994) in- uals is not known). In general, the data
dicates a close relationship of the genera available for Labordia seem to reflect ongoing
Labordia (Hawaiian endemic) and Geniostoma polyploidizationatthespecieslevelinthisge-
(of Pacific distribution). A separation of the nus. No meiotic irregularities were observed
two genera from Loganiaceae as Geniosto- in L. waialealae; the range of n¼30–34 is
maceae (proposed by Struwe et al. 1994), due to clumping of the chromosomes in the
however, is not accepted by the latest Angio- field fixation.
spermPhylogenyGroup(2003)classification. myrsinaceae: The count of 2n¼46 for
The possibility of autochthonous polyploid Myrsine sandwicensis is the first for the family
evolutionintheGeniostoma-Labordiarelation- in Hawai‘i. The result is in accordance with
shipwasdiscussedbyCarr(1998)andMotley most other data for thegenus (Dawson 1995,
andCarr(1998).They gave2n¼40forGen- Murray and DeLange 1999) and is not infor-
iostoma rupestre J. R. & G. Forst., a possible mative for phylogenetic considerations.
ancestor of Labordia. Based on published data oleaceae: The result obtained for Neste-
for Labordia (2n¼80 or 2n¼ca. 80 for L. gis sandwicensis is 2n¼44(–46). The reason
hirtella, L. waiolani [Carr 1978]; L. helleri, L. for the given range is the presence of two
kaalae, L. tinifolia, L. fagraeoidea, L. hedyosmi- smaller elements, most likely satellites but al-
folia, L. hirtella, L. hosakana, L. waialealae, L. ternatively representing two small chromo-
waiolani [Motley and Carr 1998]) and on un- somes. Skottsberg (1955) reported 2n¼44
published counts by me (Labordia degeneri: for N. sandwicensis. Counts made by Dawson
2n>40<60, L. helleri: 2n¼40–44 [cited (1995) revealed 2n¼46 for four Nestegisspe-
in Carr 1998]), the occurrence of at least cies from New Zealand. More cytological in-
two different ploidy levels in this Hawaiian vestigationsareneededtoclarifythesituation
endemic genus seemed apparent to Carr inthis genus.
.
ChromosomeNumbersofHawaiianAngiosperms Kiehn 371
orchidaceae: No chromosome counts include diploids (mostly n¼10 [e.g., Ahsan
fornativeHawaiianorchidswereavailable up et al. 1994]) and tetraploids (either n¼18
to now. The reason for the range given here [e.g., Bir and Chauhan 1990] or n¼20 [e.g.,
forLiparishawaiensisfromMaui(2n¼26–30) Gilletal.1980,Sinhaetal.1990,Ahsanetal.
is clumping of chromosomes in the field 1994]). The same range of tetraploid num-
fixation. Variation of chromosome numbers bers was obtained from analyses offield fixa-
ranging from 2n¼20 to 2n¼76 is docu- tions of Heteropogon contortus from Hawai‘i.
mented for Liparis (Goldblatt and Johnson The uncertainty reported here is due to sev-
2000), and B chromosomes are also reported eralcloseassociationsofchromosomesnotal-
in the genus (Vij and Sood 1986). Thus the lowing a more exact count. It is not clear
data reported here have no obvious syste- whetherthese associations reflectpartial mei-
matic implications. oticpairing(secondaryassociations)orarear-
pittosporaceae: Of the 11 Pittosporum tifactsofthefixations.Suchassociationscould
species endemic to Hawai‘i a previous count explainthevariationinchromosomenumbers
existed only for Pittosporum glabrum (2n¼24 reported for this species in the literature.
[Carr 1978]). Outside Hawai‘i, x¼n¼12 The report of 2n¼42–44 for Poa sandvi-
is the only reported number in the genus censisisthefirstreportforaPoaspeciesnative
(Dawson 1995), and no polyploids have been to Hawai‘i. Based on available chromosome
reported (Fedorov 1974, Carr and McPher- data, x¼7 is the prevalent basic number
son 1986). The new result for P. gayanum in the genus Poa (Goldblatt and Johnson
(2n¼24) matches the earlier results. How- 2003), indicating that Poa sandvicensis is hexa-
ever,2n¼32–36obtainedfortwocollections ploid. The fixation analyzed was a part of a
of Pittosporum, one from O‘ahu andthe other younginflorescenceofasingleindividualcul-
from Maui (neither identified to species), in- tivated at the NTBG. Mitotic numbers were
dicate the occurence of a new basic number obtained from filament tissue that was pre-
in the genus. In this context, the report of sumablydiploid(2n).Meioticdivisionsofmi-
n¼18 for the genus Citriobatus by Gros crosporocytes were present in all stages but
(1965, cited in Fedorov 1974) deserves atten- were characterized by numerous univalents
tion. The basic number for the family and andmultivalentsand,therefore,didnotallow
the genus Pittosporum is probably x¼6, and a count. These irregularities in meiosis could
the two collections from O‘ahu and Maui are be the effect of the hexaploid state of the
thus hexaploids. Further investigations, in- plant.
cluding meiotic divisions and pollen viability, primulaceae: The native Hawaiian spe-
arerequiredtobetterunderstandtheimplica- cies of Lysimachia belong to two subgenera,
tions ofthe new reports. subg. Palladia and subg. Lysimachiopsis. They
plantaginaceae: Two ploidy levels, are assumed to be the result of two separate
2n¼12 and 2n¼24, have been reported for colonization events (Wagner et al. 1999).
the Hawaiian endemic Plantago princeps (Carr Thisideaissupportedbythecytologicaldata:
1998). Three counts for this species are re- L. mauritiana, the only Hawaiian represen-
portedhere, one for P. princeps s.str.,andtwo tative of subgenus Palladia, is diploid with
for P. princeps var. anomala. All three reveal x¼10 (2n¼20 [Carr 1978, 1998]). In
2n¼24 chromosomes. The second chromo- contrast,bothHawaiian speciesofsubg. Lysi-
somally known species from Hawai‘i, P. pa- machiopsis counted so far exhibit high chro-
chyphylla, is also tetraploid with 2n¼24 mosome numbers, most probably based on
(Skottsberg 1955, Moore 1973). Thus, tetra- x¼9; 2n¼ca. 54 for L. hillebrandii was re-
ploidy seems to be prevalent in the genus in ported by Skottsberg (1955), and the count
Hawai‘i. More counts are needed to verify given here for Lysimachia glutinosa (2n¼72)
the existence ofdiploidyin Hawaiian popula- matches an earlier report by Carr (1978). It
tions ofPlantago. would be desirable to sample additional Ha-
poaceae: Based on previous reports, Het- waiian species of subg. Lysimachiopsis to assess
eropogon contortus populations outside Hawai‘i theextentofpolyploidy.Chromosomesizein
.
372 PACIFIC SCIENCE July2005
Lysimachia glutinosa is 3–5 mm in nearly fully metaphase), and it is very difficult to obtain
contractedprometaphase,thesamesizerange clearly spread metaphase plates. Thus, the
as given for other Lysimachia species (Ko et ranges of the counts reported here do not
al.1986). necessarily reflect a real range of chromo-
rubiaceae: Coprosma is represented in some numbervariationbetween individuals.
Hawai‘i by 13 species, one of which, C. erno- First counts for Hawaiian Psychotria
deoides, has black fruits and is considered to (KiehnandLorence1996)indicatedtheexis-
represent an introduction independent from tence of two ploidy levels (6x, 8x) in this
the remaining species, which have orange genus in Hawai‘i. The new count for P. mar-
fruits (Wagner et al. 1999). The cytological iniana corroborates the earlier result for this
situation in Coprosma has been discussed by species (Kiehn and Lorence 1996). Unfortu-
Kiehn (1996). New counts for orange-fruited nately all other attempts to obtain results for
species (2n¼44, 40–44) are in accordance Hawaiian Psychotria species have failed up to
with all earlier reports for Hawaiian taxa, now due to ‘‘self-tanning’’ effects in the field
which exclusively were tetraploid (5 of 12 fixations. Tannic acids present in tissues in-
species counted). A new count for C. erno- terfered with the field fixations in P. fauriei,
deoidesfromHawai‘iVolcanoesNationalPark P. greenwelliae, P. hathewayi, P. hawaiiensis, P.
revealed 2n¼254–264 chromosomes in each hexandra, and P. mauiensis, resulting in a pre-
of six analyzed cells from two seedlings. This fixation of the chromosomes, which then
is the highest chromosome number reported clumped together, making counts virtually
inRubiaceae so far. It also indicates the pres- impossible (see Greilhuber 1987, Kiehn 1995
ence of two different ploidy levels in C. erno- for discussions of this problem). Fixation of
deoides:an earlier countofthis species(Kiehn root tips of very young seedlings, which are
1996) based on material from East Maui and nearly free of tannins, may provide a means
earlier data from the literature (Skottsberg to obtain accurate chromosome counts in
1955) showed 2n¼ca. 220. More cytological these species.
studies are needed to further elucidate this rutaceae: Previous counts for Hawaiian
situation (e.g., whether the two ploidy levels species of Melicope established two ploidy
distinguish populations of C. ernodeoides from levels: 2n¼36 for M. elliptica (Carr 1978) of
East Maui and Hawai‘i Island). Evidence for sect.Apocarpa,and2n¼72forM.wawraeana
apomixis in the tetraploid C. waima from of sect. Megacarpa (Guerra 1984, as Pelea wa-
New Zealand (Heenan et al. 2002) suggests wraeana). Counts from outside Hawai‘i are
the possible occurrence of this mechanism in available for the two New Zealand species of
C. ernodeoides and could explain the regular Melicope: M. simplex and M. ternata are both
fruitsetinthisspeciesdespitemeioticirregu- reported to have n¼18 and 2n¼36 chro-
larities that are to be expected with such mosomes (Guerra 1984, Dawson and Beu-
high chromosome numbers. Further work is zenberg 2000). New results reported here for
needed to obtain additional chromosome M. barbigera (sect. Apocarpa) and for an un-
data and to test for the possible occurrence identified species from O‘ahu (both 2n¼36)
ofapomixisin C. ernodeoides. match the earlier data. However, a third
For Hedyotis, three new results are re- ploidy level is tentatively identified based
ported here: a first count for H. schlechten- on the observations made on four seedlings
dahliana subsp. remyi (2n¼94–100), a new of an unidentified species from Kaua‘i (Flynn
island report for H. centranthoides from 6630):oneseedlingclearlyexhibited2n¼18,
O‘ahu(2n¼ca.100),andanadditionalcount but the three others showed 2n¼36. The
for H. terminalis from Kaua‘i (2n¼90–100). implications of these results can only be eval-
Thenewdatafullysupporttheearlierreports uated when further countsbecome available.
ofveryhighchromosomenumbersbySkotts- sapotaceae: The report by Skottsberg
berg (1955) and Kiehn (1996). The chromo- (1955) of 2n¼48 for Pouteria sandwicensis
somes of Hawaiian Hedyotis are dotlike and could be interpreted as tetraploidy on a basic
very small (not exceeding 0.5 mm in mitotic number of x¼12 (Johnson 1991). Chromo-