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New chromosome number records of South African Oxalis species
S. Afr. J. Bot. 2000, 66(2) 130- 132
130 The anthl.!f Form. function and phylogeny, cds W G D ' ;\rq & R,C KeatIng Cambridge UniversI ty Press, Cambndgc O'BRIEN, T P & McCULLY, M .E 198 1 The study of plant structure Pnnclpl es and selected methods . Melbourne , ThermlJcarphl PRI CE, GO, MOHAPATRA , S .S . & GRESSHOF F, P.M 1984. StrucLure of nodules formed by RlII=ubwn/ strain ANU 289 in the nOI1it::gllmc Paraspomo and the legume Slratro (A/acropliflu/Il atropllrpun:ulI1) Bot. Ga= 145 441--451.
SClIV/lN TZ ER, C S & TJEPKEMA, J 0 1991 Ac!morh lza] plants Frallkw - Symhioses In : Biology and hlOchcmiSifY of lllirogen fixatllll1 , cd:; M.J Dilworth and A R. Glenn, pp 350- 372. El sevie r. Amsterdam SKENE. K R . KIE RANS. M, SPR r.::NT. J I & RAVEN , J A 1996 Sl rllclllral aspeCiS or cluster roOL developme nt and the lT pO::;sJblc significance fo r nutnent acqUlsitlon 111 Grevillea robus/a (Proteaceae) Allil. Bal. 77 ' 443- 451
SMIT. G ,N 1994 The mflm:nce of intensity of tree thinning on Mopani veld Ph D theSIS, Umvers ity ofPre\ona , Pretoria SMIT G N. & RETHMA N. N E G 1998 Root bIOmass. depth diSlribu+ lion ,nd rciallOns WIth leaf hloma" of CoiopilOspennum mopone S Afr. J. Bot. 64: 38-43
New chromosome number records of South African Oxalis species Leanne L Dreyer* and Cheryl Johnson Department of Botany , Un iversity of Stellenbosch , Private Bag X1, Matieland, 7602 Republ ic of South Afnca Received 8 [)ecember 1999: reVlsed]8 .Harch ]000
Chromosome numbers of on ly 49 Oxalis L. taxa have been pub+ Jished to date, of wh ich just 23 represent southern African taxa . Chromosome counts for the follOW ing southern African taxa are recorded here for the fi rst time: O. bltida Thunb" O. hirta l. var. tublflora Salte r and O. semiloba Sond A third reco rd for O. trunea· tula Jacq is also presented here Two previous counts for th is spe· cles have been published, one revealing a tetraploid and the other a hexaploid condition, All four taxa Included here have a basic chromosome number of x = 7 , 0, bitida and O. truncatula are both diplOid, whereas 0. hirta var. tubiflora and O. semi/oba were both found to be tetraplO id, The diplo id form of O. truneatula found here completes a po lyploid series (2x, 4x and 6x) in this species. It is concluded that karyolog ica! data can greaUy aid our understanding of the massive divers ificat ion and speciation of Oxalis in southern Africa Further cytolog ica l studies are recommended Keywords
Oxalldaceae, Oxafis, basic chromosome number,
polyplo idy ~To whom correspondence ld@land sun.ac.za) .
should
be
addressed,
(E·maJ!
Oxalis L is the largest genus in the Oxalidaceae, including about 800 species. The genus disp lays two centers of diversity, one in south-centra l America and the other in southern Africa (Marks !956). Salter (1944) completed the most recent alpha-taxonomic revision of the southern African members of the genus. He recognized 208 species. including several varieties, which he arranged into 11 sections . A tota l of270 taxa are current ly recognized w ithin southern Africa (Dreyer 1993). Cytological studies, for the genus in general and the southern African species in particular, have been very limited. Heitz ( 1927) listed chromosome numbers for 26 species, including eight so uthern African taxa. Chromosome counts for three more southern A frican taxa are given by Yamashita (1935) and one more by Warburg (1938).
Marks ( 1956) completed the most comprehensive cytologica l study for the genus to date, He published chromosome numbers for 24 addi ti onal species of which 16 are SOllth African. His work brought the total number of known chromosome numbers for southern African taxa to 23, representing a mere 8.5% of all the taxa in the region. He ide ntifi ed a basic chromosome number ofx = 7 as the most common condition in the genus , Basic num· bers of x = S, 6, 7, 9 and 1 J have, however, also been reported (Heitz 1927; Nakajima 1936 ; Wu lff 1937; Warburg 1938; Rutland 1941 ; Marks 1956 ). Marks (1956) found that the southern African species display li mited variation in basic chromosome number and size, but a fairly high occurrence of polyploidy (Table 1). In contrast. the American species are variable in terms of basic chromosome number and chromosome size. but display less polyploidy. The aim of the present study was to expand on the cytological knowledge of southern African Oxalis taxa, concentrating on taxa from the StelJenbosch area. Chromosome numbers for the following three taxa were determined: 0. b(fida Thunb., 0. semi· loba Sand. and 0. hirla L. var. Illb{flora Salter. Additionally, a third count for 0. lruncatllla Jacq. was also undertake n. Mitotic chromosome counts were performed by study ing actively dividing cells in young root tips. Suitable roots were cultivated by growing plants in Standard Long Ashton nutrient medium (Hewitt 1966) at pH 6 in 20 liter hydroponics tanks aer· ated with CO z. Root tips were harvested after 7-10 days in hydroponics and were pre-treated in 0.002 M S·hydroxyquinoline for 4 hours . Roots were then fixed in a 3: I ethanol and acetic acid mixture for 24 hours. This was followed by standard acetocarmine stain and squash techn iq ues, as described by Snow (1963). Five specimens of each spec ies were studied and counts were obtained from at least 10 cells per specimen. Chro!l1{)some numbers are given in Table 1. Oxalis semi/aba (section Cernllae, subsection Purpllmlae) was found to be tetrap loid (2 n = 4x = 28), with a bas ic chromo· some number ofx = 7. This is in accordance with the basic chromosome number reported for 0. bml'iei Lind!. and 0. purplIrala Jacq ., two species of the same subsection (Table 1). 0. plflpllra/a is also tetraploid, whereas 0. hOll'iei includes both tetraploid and hexaploid forms . Oxalis franCa/it/a (section Opposilae, subsection Subintegrae) was found to be diploid with a basic chromosome number of x = 7. This is interesting, as previous coun ts for the same species revea led tetraploid (Marks 1956) and hexaploid (Heitz 1927) forms. 0 mmcalulo thus disp lays a polyploid series, including 2x, 4.'\ and 6x forms. Cyto logically, subsection SlIhinlegme appears to be very heterogeneo us . 0 incomala L is diploid with a basic chromosome number of x = 7, whereas 0 imhricala Eckl. & Zeyh. is either tetraploid or octaploid with a basic chromosome number of either x = 5 or x = 10 (Marks 1956). Salter (1944) based the delimitation of subsection Opposilae on the occurrence of two opposite bracts at the upper or second articula· tion of the peduncle. Bayer (pers. comm.) doubts the systematic significance of this character, and regards this subsect ion as one of the most unnatural taxa delimited by Salter ( 1944). Cytological studies l11ay, therefore, prove highly sign ifi cant in the re·eval· uation of subsection Opposiwe. The karyologicaJ differences are, however, not reflected in the very uniform palynology of the sub· section (Dreyer 1996). All the included taxa have micro·reticu· late to reticulate pollen grains, with or without intraluminary bacules, We found 0. b!/lda (section Opposilae , subsection B!(urcatae) to be diploid (2n = 2.'\ = 14), a lso with a basic chromosome number of x = 7. This conforms exactly to the karyology of 0 smilhiana Ecki. & Zeyh., the only other species within the sub· section for wh ic h chromosome counts are availab le (Table 1).
S Ali' J. Bot. 2000. 66(2)
131
Table 1 Known chromosome numbers of the southern African members of Oxalis. Chromosome numbers determined In the present study are indicated in bold type face See end of table for an explanation of symbols
( '('/"Ill/a!!
I:"I/-Ce/"lIlIl/('
2n
[ ncalll\
TaXI)J1
() cerl/l{(l
Tunh
7
UnklHl\\!1
() pes-carpruc L I.I1 ' U!UI.!
() (/ellla{U .la(q
PllrjlllrO!{/ ('
() hOll l e! [
\\'~
Intll
wep
nhl.'rg Hdl.
7
i'darks (I (56)
(iralwl11st()\\!l . Fep
7
Marks (]4)6) l !clt/(1927)
28
7
..Jx
o
unkllo\\ n
20
5(10)
4x(2,)
(irahamstl)\\ll. FC'[l
h
h :h.1 8.:
() IIlu/rna/a
L
Camhridge BolamI.' {iarden
() (rUlJco/u/a
Jacq
UnklH)\\ 11
() fl"ll/nufl/fu
.Iaeq
O. frIlllCllfllla
,lac£!.
Ld.1 (\: /
Kn~snd .
2X
h
() Cuf/h.'fa
[>({I"
llre)er & .John.'>on
7
Dreyer & John.\ on
7
Iklti' (19271
7
Marks (1050)
7
Marks ( 1956)
weI'
UnkllO\lll
(iClne~.
Namaqua[ano . NCP
KaJllle~kro[)n,
0.
1//(/.\".1"011/(/11(1
Salter
Vall
7
Rh~n ' s
Nep
WOreeSIl'r. WCP
30
() /III"/a I.
LlI1J....n(l\\ 11
30
O. IJirtll L val'. tuhiflol"{f Saite l'
StelleniHl.~ch,
111111"1.\ .1aclj (imll C
()
CIIII(,(//(/
Jacq
wep
7
Marks (195(,)
Marks ()lJ561
s.\.
5( 10)
X'\(.Jx)
YamashIla ( 1935)
30
30
Mark-. (195h) Marks (1Y561
12
131ShopscotIrt. WCP
haslC chromosome nllmher . WC!,
t\.iarJ...s(1956)
Hell/ (1927)
30
=
7
7
unknO\\"ll
snmalH: chromosome numher . '\
Marks (1956)
2X
L
vt'/".moto}" L
7
Drc)cr & Johnson
unknown
o
Warhurg (193Xj
7
1\1ontagll. \\'cr' B11lcrlilllh:lll. \\'CP
.J.\
28
() "as/c%}" I. () w}".\·/c%r
=.
28
Pa.:;s. NCP
() pohphylla .lacq 'af pel//(!I' ln 1/(1 (Snns) Salin unl'dHlI\ n
2n
1~
KlrS[l'llb()~eh . WCP
t
Marks ( ]956)
7
Salter
()
2.'1:
Cape Town, \\ CP
Unkllll\\ n
""Il'(//"I.',
7
fieJ\.1.(1927)
I/(I/I/(/ljll(1l1(1
IIl1"1a I Illnn]'
l\1arks ( 1956)
7
o
()
g.\( -1 .\ )
ullJ....n{l\\ 11
unknown
SOIlO
5( 10)
Marks (1950)
() /iI/1u('jiJ/w.laeq form [3
() purdall.l" Si!.'i\·ili/O/lllfile
Saltl.:r
Heltz( l927)
7
Stellenbosch, e~
Drc:yer & Johmon
iv1arks (1956)
7
wcr
() IlJlbrtw((/
O. hifida Thunb.
Marks (1950)
7
Cape To\\n, WCP
!e~
YnmaShlla(1935)
Kc\\ 130!,lI1Ic Garden
() I'II/purea I
/lIgll.l"faw('
2x
0. .\ 'l!lIliloh(f Sond. eaprll/a!
Rcfen:ncc
Mark.s (1<)."6)
7
() SJlllliJlUllu
( ·/"a.I .I/llae
:'\x
2X
() lragopoda Salter
H/jim afoe
pJOld~
unkntl\\11
Jacq
() /J//ljJu/"U{(I
S!lb!llr~'gul<
LI.'\d of
7
() hOll lol.lndJ
Slc/luwc
.,
(,
I klt/ ( 1927) IJellz{1927)
=
Wesl ern ("(lpe PT\n
IIlCt: . ]:("P =
6.\
Yarnashlla{I(}35l Marks (1956)
!-.
t:rn ( ' apt: Pwvl11et:
T\\D chromosome counts are available for the typical variety of () hil"/a (section .·Inglls/afar..', subsection .'J!..'ssi/i/o/iaw!..'). i\larks (1 (56) studied () 11lf1{/ form E (Salter 1(44) and found it
to be hc:'\aploid \',ith a basic chromosome number of x - 5. This agreed with earlier counts of an unspecified form of the same la.\ on (Yamashita 1(35). \\e found 28 chromosomes in () !linu val'. IlIh!/lo/"{/, which suggests a different base !lumber of :'\ = 7
and a tetraploid condition for this variety. The presence of two different basic chromosome numbers within the same species questions the integrity of the species as such. A thorough cytological evaluation of all the variet ies induded under U hirla seems necessary . Palynological st udies (Dreyer 19(6) also revealed an unique pollen type in () 11I1"Ia var. flIhi/lo/'(J, quite different to the pollen of the typical variety.
s.
132 '1\\10 of the fOLIf ta.xa we s tudied were found to be tetraploid. while counts of () 'fullcafll/o revealed a diploid condition in a ta.xon already kn owJl to inclu de tetraploid and hexa plo id forms . These results further extend lhe suspected high occurre nce of polyplo idy among the sOllt hern A fr ican members of ()xalis. The differe nce in bas ic chromosome nu mber between the Iwo varieties of O. hirla may indi cate that base num ber variations afC more commo n th an previ ousl) thought. Results fro lll this stu dy suggest that karyology can be instrumen tal in our understanding or the massive dive rs ification and speciation among the southern African memhers of the Owlis . Further cy tological ,vark is
Ali·. J. BOl.l000. 66(2)
A t'rH.:a Ph 0 theSIS, UIU\,l.! fSJt) of Pretoria, !'rdona ;lb~rrante Chrollwso!l1J:i1!Jkn ..Ihfrh
HEITZ. 1'-: 1927 Uhef mllitlpk und
Geh Sa/lin!'. llamburg 2 1 -17 HFW1TT, E .I 1900 Santi and water l:ultun: methods
lIs~d III
the
~tud~
of plant 11lHntlOll. 2 nd r~\ised edition COflHllOll\\ealth Bu reau of Hort icu llUn: and Plantati on Crops. East Malling T~dl!1i r.:al Com Illunication 12. Farnham Royal. Un ited Kingdum NI\KA.Ili'-1 A G 1936 Chromosoille numbers anglOsr~ rms
MI\RKS.
(i
111
some crnp and \\ll d
.lap J (reller 12 211
F 1956 ChWnlOSOml' Ilumbers
III
Ihe ge1lUS Ovalls \('11
I'hy/ol 55 120 129
strong ly rec om mended .
RlJT I.,\NJJ. J P 1941 Th .: Merton Calaloque X(')! !'hl 'fll/ -10 21U SA! TI·:R. TM 194-1 The getHlS o.w/is 111 southern . \Jhca J ,\' ..JJi· /3o(
Acknowledgements We than k the Unive rsity of Stcllcnbosl:h for financ ial support and Dr Lf\.1. M
Supp! Vol I 1-3 55 SNO\.\ . R 1963 Alcoholic h)drm:hlorIl: antl-carnlllh: as a staHl tix chromusn11lCS 111 squash preparattons S/(/III TechI/O/ 31{ 9- 13 ra x()nol1l~ and re[all1lJlsh lPS mlhe (ierarl1a!cs III thl.'ltghtllfthclrcytnlog) Sell I'h.\/ol 37 lH9 WU1.FF, f! ]) 1937 CllrOll\(\So111":11 StUdlCl1 an dl'r sl:hk:;\~ l gh(1lstelt1\.\AIHi ti !Hi , I: F 1938
References DRI·YER . L 1 1993 O.xi.l[ld'H:~al.! [n o Plants of southan AfrICa names and dlstnbutHln . eds Arno[d & De \V~t .\lelll hen. ,\UrI" S .'//1' ('2 -13(1--1-12 ])RLYER. L I. 19% 1\ pa[\IlO]oglCal n;:nl.'\\ 01' Ora/IS III soulhern
lsel1t'1l Angl 0s pcrmell - Fl ora 1 IJe/' df hoI C;es 5) 262 YI\MAS! IIT/\. K 1935 7.ytn lnglSdh' SludJl.'n an (}:W/i.I' J .lap J
II 30
(;t'ITt'1
130 The anthl.!f Form. function and phylogeny, cds W G D ' ;\rq & R,C KeatIng Cambridge UniversI ty Press, Cambndgc O'BRIEN, T P & McCULLY, M .E 198 1 The study of plant structure Pnnclpl es and selected methods . Melbourne , ThermlJcarphl PRI CE, GO, MOHAPATRA , S .S . & GRESSHOF F, P.M 1984. StrucLure of nodules formed by RlII=ubwn/ strain ANU 289 in the nOI1it::gllmc Paraspomo and the legume Slratro (A/acropliflu/Il atropllrpun:ulI1) Bot. Ga= 145 441--451.
SClIV/lN TZ ER, C S & TJEPKEMA, J 0 1991 Ac!morh lza] plants Frallkw - Symhioses In : Biology and hlOchcmiSifY of lllirogen fixatllll1 , cd:; M.J Dilworth and A R. Glenn, pp 350- 372. El sevie r. Amsterdam SKENE. K R . KIE RANS. M, SPR r.::NT. J I & RAVEN , J A 1996 Sl rllclllral aspeCiS or cluster roOL developme nt and the lT pO::;sJblc significance fo r nutnent acqUlsitlon 111 Grevillea robus/a (Proteaceae) Allil. Bal. 77 ' 443- 451
SMIT. G ,N 1994 The mflm:nce of intensity of tree thinning on Mopani veld Ph D theSIS, Umvers ity ofPre\ona , Pretoria SMIT G N. & RETHMA N. N E G 1998 Root bIOmass. depth diSlribu+ lion ,nd rciallOns WIth leaf hloma" of CoiopilOspennum mopone S Afr. J. Bot. 64: 38-43
New chromosome number records of South African Oxalis species Leanne L Dreyer* and Cheryl Johnson Department of Botany , Un iversity of Stellenbosch , Private Bag X1, Matieland, 7602 Republ ic of South Afnca Received 8 [)ecember 1999: reVlsed]8 .Harch ]000
Chromosome numbers of on ly 49 Oxalis L. taxa have been pub+ Jished to date, of wh ich just 23 represent southern African taxa . Chromosome counts for the follOW ing southern African taxa are recorded here for the fi rst time: O. bltida Thunb" O. hirta l. var. tublflora Salte r and O. semiloba Sond A third reco rd for O. trunea· tula Jacq is also presented here Two previous counts for th is spe· cles have been published, one revealing a tetraploid and the other a hexaploid condition, All four taxa Included here have a basic chromosome number of x = 7 , 0, bitida and O. truncatula are both diplOid, whereas 0. hirta var. tubiflora and O. semi/oba were both found to be tetraplO id, The diplo id form of O. truneatula found here completes a po lyploid series (2x, 4x and 6x) in this species. It is concluded that karyolog ica! data can greaUy aid our understanding of the massive divers ificat ion and speciation of Oxalis in southern Africa Further cytolog ica l studies are recommended Keywords
Oxalldaceae, Oxafis, basic chromosome number,
polyplo idy ~To whom correspondence ld@land sun.ac.za) .
should
be
addressed,
(E·maJ!
Oxalis L is the largest genus in the Oxalidaceae, including about 800 species. The genus disp lays two centers of diversity, one in south-centra l America and the other in southern Africa (Marks !956). Salter (1944) completed the most recent alpha-taxonomic revision of the southern African members of the genus. He recognized 208 species. including several varieties, which he arranged into 11 sections . A tota l of270 taxa are current ly recognized w ithin southern Africa (Dreyer 1993). Cytological studies, for the genus in general and the southern African species in particular, have been very limited. Heitz ( 1927) listed chromosome numbers for 26 species, including eight so uthern African taxa. Chromosome counts for three more southern A frican taxa are given by Yamashita (1935) and one more by Warburg (1938).
Marks ( 1956) completed the most comprehensive cytologica l study for the genus to date, He published chromosome numbers for 24 addi ti onal species of which 16 are SOllth African. His work brought the total number of known chromosome numbers for southern African taxa to 23, representing a mere 8.5% of all the taxa in the region. He ide ntifi ed a basic chromosome number ofx = 7 as the most common condition in the genus , Basic num· bers of x = S, 6, 7, 9 and 1 J have, however, also been reported (Heitz 1927; Nakajima 1936 ; Wu lff 1937; Warburg 1938; Rutland 1941 ; Marks 1956 ). Marks (1956) found that the southern African species display li mited variation in basic chromosome number and size, but a fairly high occurrence of polyploidy (Table 1). In contrast. the American species are variable in terms of basic chromosome number and chromosome size. but display less polyploidy. The aim of the present study was to expand on the cytological knowledge of southern African Oxalis taxa, concentrating on taxa from the StelJenbosch area. Chromosome numbers for the following three taxa were determined: 0. b(fida Thunb., 0. semi· loba Sand. and 0. hirla L. var. Illb{flora Salter. Additionally, a third count for 0. lruncatllla Jacq. was also undertake n. Mitotic chromosome counts were performed by study ing actively dividing cells in young root tips. Suitable roots were cultivated by growing plants in Standard Long Ashton nutrient medium (Hewitt 1966) at pH 6 in 20 liter hydroponics tanks aer· ated with CO z. Root tips were harvested after 7-10 days in hydroponics and were pre-treated in 0.002 M S·hydroxyquinoline for 4 hours . Roots were then fixed in a 3: I ethanol and acetic acid mixture for 24 hours. This was followed by standard acetocarmine stain and squash techn iq ues, as described by Snow (1963). Five specimens of each spec ies were studied and counts were obtained from at least 10 cells per specimen. Chro!l1{)some numbers are given in Table 1. Oxalis semi/aba (section Cernllae, subsection Purpllmlae) was found to be tetrap loid (2 n = 4x = 28), with a bas ic chromo· some number ofx = 7. This is in accordance with the basic chromosome number reported for 0. bml'iei Lind!. and 0. purplIrala Jacq ., two species of the same subsection (Table 1). 0. plflpllra/a is also tetraploid, whereas 0. hOll'iei includes both tetraploid and hexaploid forms . Oxalis franCa/it/a (section Opposilae, subsection Subintegrae) was found to be diploid with a basic chromosome number of x = 7. This is interesting, as previous coun ts for the same species revea led tetraploid (Marks 1956) and hexaploid (Heitz 1927) forms. 0 mmcalulo thus disp lays a polyploid series, including 2x, 4.'\ and 6x forms. Cyto logically, subsection SlIhinlegme appears to be very heterogeneo us . 0 incomala L is diploid with a basic chromosome number of x = 7, whereas 0 imhricala Eckl. & Zeyh. is either tetraploid or octaploid with a basic chromosome number of either x = 5 or x = 10 (Marks 1956). Salter (1944) based the delimitation of subsection Opposilae on the occurrence of two opposite bracts at the upper or second articula· tion of the peduncle. Bayer (pers. comm.) doubts the systematic significance of this character, and regards this subsect ion as one of the most unnatural taxa delimited by Salter ( 1944). Cytological studies l11ay, therefore, prove highly sign ifi cant in the re·eval· uation of subsection Opposiwe. The karyologicaJ differences are, however, not reflected in the very uniform palynology of the sub· section (Dreyer 1996). All the included taxa have micro·reticu· late to reticulate pollen grains, with or without intraluminary bacules, We found 0. b!/lda (section Opposilae , subsection B!(urcatae) to be diploid (2n = 2.'\ = 14), a lso with a basic chromosome number of x = 7. This conforms exactly to the karyology of 0 smilhiana Ecki. & Zeyh., the only other species within the sub· section for wh ic h chromosome counts are availab le (Table 1).
S Ali' J. Bot. 2000. 66(2)
131
Table 1 Known chromosome numbers of the southern African members of Oxalis. Chromosome numbers determined In the present study are indicated in bold type face See end of table for an explanation of symbols
( '('/"Ill/a!!
I:"I/-Ce/"lIlIl/('
2n
[ ncalll\
TaXI)J1
() cerl/l{(l
Tunh
7
UnklHl\\!1
() pes-carpruc L I.I1 ' U!UI.!
() (/ellla{U .la(q
PllrjlllrO!{/ ('
() hOll l e! [
\\'~
Intll
wep
nhl.'rg Hdl.
7
i'darks (I (56)
(iralwl11st()\\!l . Fep
7
Marks (]4)6) l !clt/(1927)
28
7
..Jx
o
unkllo\\ n
20
5(10)
4x(2,)
(irahamstl)\\ll. FC'[l
h
h :h.1 8.:
() IIlu/rna/a
L
Camhridge BolamI.' {iarden
() (rUlJco/u/a
Jacq
UnklH)\\ 11
() fl"ll/nufl/fu
.Iaeq
O. frIlllCllfllla
,lac£!.
Ld.1 (\: /
Kn~snd .
2X
h
() Cuf/h.'fa
[>({I"
llre)er & .John.'>on
7
Dreyer & John.\ on
7
Iklti' (19271
7
Marks (1050)
7
Marks ( 1956)
weI'
UnkllO\lll
(iClne~.
Namaqua[ano . NCP
KaJllle~kro[)n,
0.
1//(/.\".1"011/(/11(1
Salter
Vall
7
Rh~n ' s
Nep
WOreeSIl'r. WCP
30
() /III"/a I.
LlI1J....n(l\\ 11
30
O. IJirtll L val'. tuhiflol"{f Saite l'
StelleniHl.~ch,
111111"1.\ .1aclj (imll C
()
CIIII(,(//(/
Jacq
wep
7
Marks (195(,)
Marks ()lJ561
s.\.
5( 10)
X'\(.Jx)
YamashIla ( 1935)
30
30
Mark-. (195h) Marks (1Y561
12
131ShopscotIrt. WCP
haslC chromosome nllmher . WC!,
t\.iarJ...s(1956)
Hell/ (1927)
30
=
7
7
unknO\\"ll
snmalH: chromosome numher . '\
Marks (1956)
2X
L
vt'/".moto}" L
7
Drc)cr & Johnson
unknown
o
Warhurg (193Xj
7
1\1ontagll. \\'cr' B11lcrlilllh:lll. \\'CP
.J.\
28
() "as/c%}" I. () w}".\·/c%r
=.
28
Pa.:;s. NCP
() pohphylla .lacq 'af pel//(!I' ln 1/(1 (Snns) Salin unl'dHlI\ n
2n
1~
KlrS[l'llb()~eh . WCP
t
Marks ( ]956)
7
Salter
()
2.'1:
Cape Town, \\ CP
Unkllll\\ n
""Il'(//"I.',
7
fieJ\.1.(1927)
I/(I/I/(/ljll(1l1(1
IIl1"1a I Illnn]'
l\1arks ( 1956)
7
o
()
g.\( -1 .\ )
ullJ....n{l\\ 11
unknown
SOIlO
5( 10)
Marks (1950)
() /iI/1u('jiJ/w.laeq form [3
() purdall.l" Si!.'i\·ili/O/lllfile
Saltl.:r
Heltz( l927)
7
Stellenbosch, e~
Drc:yer & Johmon
iv1arks (1956)
7
wcr
() IlJlbrtw((/
O. hifida Thunb.
Marks (1950)
7
Cape To\\n, WCP
!e~
YnmaShlla(1935)
Kc\\ 130!,lI1Ic Garden
() I'II/purea I
/lIgll.l"faw('
2x
0. .\ 'l!lIliloh(f Sond. eaprll/a!
Rcfen:ncc
Mark.s (1<)."6)
7
() SJlllliJlUllu
( ·/"a.I .I/llae
:'\x
2X
() lragopoda Salter
H/jim afoe
pJOld~
unkntl\\11
Jacq
() /J//ljJu/"U{(I
S!lb!llr~'gul<
LI.'\d of
7
() hOll lol.lndJ
Slc/luwc
.,
(,
I klt/ ( 1927) IJellz{1927)
=
Wesl ern ("(lpe PT\n
IIlCt: . ]:("P =
6.\
Yarnashlla{I(}35l Marks (1956)
!-.
t:rn ( ' apt: Pwvl11et:
T\\D chromosome counts are available for the typical variety of () hil"/a (section .·Inglls/afar..', subsection .'J!..'ssi/i/o/iaw!..'). i\larks (1 (56) studied () 11lf1{/ form E (Salter 1(44) and found it
to be hc:'\aploid \',ith a basic chromosome number of x - 5. This agreed with earlier counts of an unspecified form of the same la.\ on (Yamashita 1(35). \\e found 28 chromosomes in () !linu val'. IlIh!/lo/"{/, which suggests a different base !lumber of :'\ = 7
and a tetraploid condition for this variety. The presence of two different basic chromosome numbers within the same species questions the integrity of the species as such. A thorough cytological evaluation of all the variet ies induded under U hirla seems necessary . Palynological st udies (Dreyer 19(6) also revealed an unique pollen type in () 11I1"Ia var. flIhi/lo/'(J, quite different to the pollen of the typical variety.
s.
132 '1\\10 of the fOLIf ta.xa we s tudied were found to be tetraploid. while counts of () 'fullcafll/o revealed a diploid condition in a ta.xon already kn owJl to inclu de tetraploid and hexa plo id forms . These results further extend lhe suspected high occurre nce of polyplo idy among the sOllt hern A fr ican members of ()xalis. The differe nce in bas ic chromosome nu mber between the Iwo varieties of O. hirla may indi cate that base num ber variations afC more commo n th an previ ousl) thought. Results fro lll this stu dy suggest that karyology can be instrumen tal in our understanding or the massive dive rs ification and speciation among the southern African memhers of the Owlis . Further cy tological ,vark is
Ali·. J. BOl.l000. 66(2)
A t'rH.:a Ph 0 theSIS, UIU\,l.! fSJt) of Pretoria, !'rdona ;lb~rrante Chrollwso!l1J:i1!Jkn ..Ihfrh
HEITZ. 1'-: 1927 Uhef mllitlpk und
Geh Sa/lin!'. llamburg 2 1 -17 HFW1TT, E .I 1900 Santi and water l:ultun: methods
lIs~d III
the
~tud~
of plant 11lHntlOll. 2 nd r~\ised edition COflHllOll\\ealth Bu reau of Hort icu llUn: and Plantati on Crops. East Malling T~dl!1i r.:al Com Illunication 12. Farnham Royal. Un ited Kingdum NI\KA.Ili'-1 A G 1936 Chromosoille numbers anglOsr~ rms
MI\RKS.
(i
111
some crnp and \\ll d
.lap J (reller 12 211
F 1956 ChWnlOSOml' Ilumbers
III
Ihe ge1lUS Ovalls \('11
I'hy/ol 55 120 129
strong ly rec om mended .
RlJT I.,\NJJ. J P 1941 Th .: Merton Calaloque X(')! !'hl 'fll/ -10 21U SA! TI·:R. TM 194-1 The getHlS o.w/is 111 southern . \Jhca J ,\' ..JJi· /3o(
Acknowledgements We than k the Unive rsity of Stcllcnbosl:h for financ ial support and Dr Lf\.1. M
Supp! Vol I 1-3 55 SNO\.\ . R 1963 Alcoholic h)drm:hlorIl: antl-carnlllh: as a staHl tix chromusn11lCS 111 squash preparattons S/(/III TechI/O/ 31{ 9- 13 ra x()nol1l~ and re[all1lJlsh lPS mlhe (ierarl1a!cs III thl.'ltghtllfthclrcytnlog) Sell I'h.\/ol 37 lH9 WU1.FF, f! ]) 1937 CllrOll\(\So111":11 StUdlCl1 an dl'r sl:hk:;\~ l gh(1lstelt1\.\AIHi ti !Hi , I: F 1938
References DRI·YER . L 1 1993 O.xi.l[ld'H:~al.! [n o Plants of southan AfrICa names and dlstnbutHln . eds Arno[d & De \V~t .\lelll hen. ,\UrI" S .'//1' ('2 -13(1--1-12 ])RLYER. L I. 19% 1\ pa[\IlO]oglCal n;:nl.'\\ 01' Ora/IS III soulhern
lsel1t'1l Angl 0s pcrmell - Fl ora 1 IJe/' df hoI C;es 5) 262 YI\MAS! IIT/\. K 1935 7.ytn lnglSdh' SludJl.'n an (}:W/i.I' J .lap J
II 30
(;t'ITt'1