- Email: [email protected]
The taxonomic status of Sarcocaulon (Geraniaceae)
345
S. Mr. I. Bot. 1996. h2(6): 345-347 BELL. K.L.. HI ATT. H.D. & NILES. W.E. 1979. Seasonal changes in
hiomass allocation in eight winter annuals of the Mojave Desert. 1. fcot. 67 : n 1- 7H7. BENEKE. K .• VAN ROOYEN. M.W. & THERON . G.K. 1992. Fruit polymorphism in ephemeral species of Namaqualand: 6. lntermorphic competition amo ng plants cultivated from d imorphic diaspore s. S. Afr. 1. Yot. Sg: 461--468. CLARK. D.O. & BURK, J.H. 19RO. Resource allocation patterns of two Ca liforma Sonoran Desert ephemera Is. Oet:lI{og;o (Berlin) 46: R6-'J I . CONNOLLY. J. J9H6. On difficulties with rcpi acemenHcnes methodology in mixture ex periments. J. appl. £1.:01. 23: 125- 137.
DE WIT, C.T. 1960. On competition. Ventog LllIulbollwklll1tiigc Ollder(.
6h: 1-82. DURA LI A. T.E. & READER.R.J. IY93 . Docs abundance renect competitive ability?: A test with three prairie grasses. Oikos 68: 82-90 . FIRB ANK, L.G . & WATK INSON, A. R. 1985. On the analysis of competition within two species mixtures of plants. J. oppl. E<:o/. 22: 503 517. FOWLER. N. 1982. Competition and coex istence i n a North Carol ina grassland. J. EC(I/. 70; 77-92. GAUSE, G,F. 1934. The struggle for existe nce_Waverly, Baltimore. GOLDBER G, D.E. & BARTON, A.M. 1992. Patterns and consequences of interspeci fic compe tition in natu ral comm unities: a revIew of field expe riments with plants. Am. Nat. 139: 77 1- 80 I. HALL, R.L. 1974. A naly sis of the nillure interference between plants of different species: I . Concepts and extension of the Dc Wi[ analysis to examine effec ts. AII.~": J. ngric:. Re.'i. 25; 73 9- 747. HARPER, J.L. 1977. Population biology of plants. Academic Press. London. LAURI, H. & COWLING, R.M. 1994. Lottery coexistence models ex tended to plants with disjoint generati ons. J. wg. Sci. 5: 161 - 168. HEW ITT, E.T. 1962. Sand and water cu lture methods used in the study of plan t nutrition. Farnham Royal, Bucks, Commonwealth Agricultura l Bureau. JOLIFFE. P.A .• MINJAS. A.N. & RUNECKLES. V.C. 1984. A reinterpretation of yield relationships in replacement series experiments. J. orf/I. Eco/. 21: 227-243. KEDDY, P.A. 1989. Compelition. Chapman & HalJ. London. MACK, R.N. & HAR PER, J,L. 1977. Interference in dune annuals: Spatial pattern and neighbourhood effects. 1. £<"01. 65: 345-363. MCGILCHRIST. C.A. & TRENBATH. B .R. 1971. A rev ised analySIS of plant competition experiments. Bi(Jmetril.:,t 27: 659-671. MEAD, R. 1979. Competition experiments. Biometric.\' 35: 4 1-54. RoSC H. H. I Y96. Li fe history strategies of Namaqualand pioneer plant spec ies. M.Sc. ui ssenation, University of Pretoria, Pretori a. SHIPLEY, B. & KEDDY, P.A. 1994. Evalu ating the ev idence for competitive hierarchies in plant commun ities. Oikm 69: 340-345. SHMIDA, A. & ELLNER. S.P. 1984. Coexistence of plants with simil ar niches. Vegetario 58: 29- 55. SILVERTOWN, J.W. & LOVETT DOUST, J. 1993 . Introduction to plan t popUlation biology. Blackwell, Oxford. SNAYDON. R.W. 1991. Replacement or addi tive design for competi ti on studies? 1. app l. Er.:ol. 28: 930--946. STEYN . A.G.W.. SM ITH. C.F. & DU TOIT. S.H.C. 1987. Moderne statistiek in die praktyk, 4th cdn. Sigma, Pretoria. TAYLOR, D .R. & AA RS SEN, LW. 1989. On the density dependence of replacement series competition ex periments. J. Et.'ol. 77: 975-988. TRENBATH, B.R. 1974. Biomass productivity of mixtures. Adv, Agron. 26: 177-210. VAN ROOY EN, M .W, 1988. Ekofis iol og iese studies van die efemere van Namakwaland. Ph.D. thesis, Uni versi ty of Pretoria. Pretoria. WILSON, J.B. 1988. ShOal competition and root competition. J. appl. Et.'(J/. 25: 279-296.
or
The taxonomic status of Sarcocauloll (Geraniaceae) F. Albers Institut fOr Botanik , Westfalische -Wilhelms-Unive rsitat. Schlossgarten 3, 0·48 149 Munster , Germany Received J October lYY6; r('viud 2-1 October J99fJ
The circu mscription of Sarcocaulon and Monsonia is reconsidered in view of th e morphological diversity in the closely related genus Pe/argonium. SEM studies of the and roecium ontogeny reveal that there is no reason for maintaining Sarcocaulon and Monsonia as separate genera. The gross morphologica l characte rs currently used to separate the two genera occur also in severa l sections of Pelargonium. Karyologic, ch em otaxonomic and DNA studies also su pport the lumping of the two genera. The necessary taxonomic changes are made. Keywords : Generic Sarcocau/on.
delimitation.
Geraniaceae ,
Mansonia,
De Candolle (1824) descri bed Sarcocllulon as a nl.!w section within the ge nu s M OllS(mia L (Gcraniaceae). However, Sweet ( 1826) excluded Sarcocflll lcm and raisetl it to generic rank. Knuth (1912) used androecium morphology charac ters, apart from growth form characters. as fu rthe r evidence for mai nta ining the two as separate genera. Sarcoc(/ulon has since been di st ingui shed from Monsonia on the basis of its th ick . more or less succulent and often woody stem s and free stamens as opposed to the mo stly herbaceous stem s and basa lly connate stamens in M OlIsoIlia. Moffet! (1979) and Venter (1979) adopted th is c lass ification and presented revisions of Sarcocauioll and MOllsonia respecti vely, maint aining them as separate genera. They al so provi ded historical reviews and nomenclatural changes, and created SI.!Ction s within these genera. Multi disciplinary studies of most of the spec ies in the closel y related ge nus, Pe/argoll illlll, have cast serious doubt on the long-held views on Sarcocauloll and M OIlsonia as two di stinct ge nera. The key characte rs used to separate them occur also in a range of Pelargollillln sections. The differentiation of Monsonia and SarC:OC(lIlJOI! is main ly based on the gross morphology. In cont ras t to the predominantly herbaceous stems of M OllSollia species, those of Sa rcoc(1II1on form thick , more or less woody to succu lent, oflen spi nescent stems. In closely related Pclargol1illlll species, similar differences in growth forms are frequently fou nd in co mparable habitats. Many species of Pelargonillln sec t. Corl(lsill(/ (DC.) Harv. (e.g. Dreyer ef al. 1992) and sect. Otidia ex hibi t similar growth forms and often share the arid habitats wi th species of Sarc:ocaulon. M onsollia and SarCOC(llf/OIl have a similar nower structure but Knuth (1912) observed a difference in the androeci um in selected species of the two genera. He pointed out that the 15 stamens of Monsonia are grouped together and are connate at the base, whereas in Sa rcOC(lu/OII, the 15 stamens an: all free. This was why he maintained Sa rcoc{/uioll and Monsonia as separate genera. SEM stu dies on the ontoge ny of androcce ium develop mellt have demonstrated that there is no diiTerence between Mansonia and Sarc{)cliuloll (Lobbert 1994: Albers & L6bbert 1996). a fac t also noted by Venter (1979).
Studies on non-morphological aspects such as phenolic compou nds (Marschewski 1995), prote in patterns (Tou loumen idou 1996) and a variety of basic chromosome numbers (Monsonia, x = 8. 9. 10. II . 12; SII reoellll/oll , .t = I I ) (A lbers. unpubli shed) support the lumping of the two taxa. Based on rbcL sequence comparisions, Price and Palmer ( 1993) observed that M onsonia and Sarcocaulon an:! either sister genera or congeneric. The dif-
346
S. Afr. J. Bot. 19%.62(6)
ft.:rcnces bl!twl.!cn [he Pe/argonillm natural entities (sections)
Monsonia h errei (L.Bollls) F. Albers. comb. nov.
afC
striking ly larger.
;;;; (Sarcocau/oll herrei L. Bolus. S. Afr. Oard. 22: 10 (1932).
The known chromoso me numbers of the MOllsollja s. sir. s pc ~
des do not support the current (Kcrs 1968) or thl.! former cuncepts (De Candollc 1824; Boissicr 1867; Knuth 1912) of sectional division. The necessary revision of the intragcneric classification of the spedcs hasell on chromosome numbers can be expected in view of the importance of the karyological characters as good taxonomic markers for differentiating sections of PelargOllilllll (e.g. Albers e t al. 1992; Dreyer el a/. 1992). The sect. SarCOC(llI/OIl forms a well-circumscribed taxon within the genus Monsonia. The sect. Sarcoc(lu/oll is distributed mai nl y in the western parts of South Africa (the true winler-rainfaJl area) and Namibia, and one species is also found in southern Ango la. Two species occur in the arid regions of the Eastern Cape Province of South Africa (su mmer-rainfall area) (Moffett 1979; Cra ib 1(95). Th~se species arc we ll adapted to the arid karroid and desert conditions. MOflSonin has a much wider distribution over Africa and into Arabia and India. The simi lari ties in the growth fo rms in species of Sa rcocnu/oll , Mcmsollia and Peim~~ oHillm are most likt:ly a result of parallel evo lution in similar habitats. In the absence of reliable morpholog ical characters fo r separating Sarcocmt/vll from MOllsonia. it is considered unavoidable to resurrect De Candollc's ( 1824) cJassilication. Sarcoc(lltloll (DC) Sweet is therefore rcsunk under MOII.wmia L. Accord in g to Dc Candollc ( 1824), Sarcocauloll species form a secti on of their ow n within Monsonin s.l. The sectional divisions of Sarcocaulol1 created by Moffett (1979) are based only on leaf morphological characters, which are strongly in fluenced by environmental condi ti ons. and are therefore plastic and unreliable. Moffett'S (1979) sectional divisions within SarcoCfmloll are therefore rejected here and the 17 new combinations and accepted species are as follows:
MOllsollia L. sect. Sarcocauloll DC., Prodr. I: 638 (1824) "SarcoC
= Sarcocal/lol! sect. Crell(l{wn Moffett, Bothalia 12: 596 (1979). Type: S. cl'llssiwuie Rehm. Bot. Jahrb. Syst. 67: 271 ( 1935).
= Sa rcncalilon sect. DelltiClilatum Moffett, BothuJia 12: 602 (1979), Type: S. mossamedellse (Welw. ex. Oliv.) Hiem., Cat.
Afr. PI. Wclw. I: 108 (1896). = Sarcocau/oll sect. Mllltifidum Moffett, Bothalia 12: 607 ( 1979). Type: S. l1lultifidul1l E. Mey. ex Knuth, pnanzenr. 4.
129: 312 ( 19 12). Type species: M. spinosa L'Hcrit. 111onsollia camdeboense (Moffett) F. Alhers. comb. nov. ;;;; (Sarcoc:au(oll camdebocnse Moffett. Bothalia 12: 593 (1979). Mansonia ciliata (Moffert) F. Albers. comb. nov. " (Sarcocauloll cifiatum Moffett, Both.lia 12: 600 (1979). Mansonia crassicaule (Rehm) F. Alhers. comb. nov. =:
(Sarcoc(luloJi crassicaule Rehm, Bol. Iahrb. Syst. 67: 271 (1935). M01lS0lliajlavesce1ls (Rehm) F. Albers. comb. nov.
;;; (Sarcoc(lulon f/avescens Rchm. Bot. lahrb. Syst. 67: 271 ( 1935).
MOllsonia inerme (Rehlll) F. Alhers, comb. nov. (Sarcocau/oll il/crme Rehm. Bot. Jahrh. Syst. 67: 269 (1935).
=:
Mansonia marlothii (Engl.) F. Albers, comb. nov. ;;;; (Sarcocau/oll m(lr/olhii Engl., BOL lahrb. Syst. 10: 31 ( 1889). Mansonia mossamedellse WelH'. ex Oliv., FL Trap. Afr. 1: 290 ( 1868). =: (Sarcocau/oll lIlossamedellse (\Velw. ex Oliv.) Hiem, Cat. Afr. PI. Wclw. I: 108 (1896). Mansonia multi/ida (E. Mey. e.\ [Kll uth] F. Albers L. Bal., Flower. PI. Afr. 10: t. 399 (1930). E (S(lrcoc(luloll I1l1tlti{tdlll1l E. Mey. ex Knuth. PJlanzenr. 4. 129: 3 12 (19 12).
MOI/sollia patersollii DC. ; Prodr. I: 638 (1824). ;;;; (Sarcocall /oll patersollii (DC.) G. Don, Gen. Syst. I : 715 (183 1). MonsolJiapeniculilJa (Moffett) F. Albers, comb. nov. =:
(Sarcocallfo ll pellicu/illlllll Motlett, Bot ha1i a 12: 610 ( 1979). Monsonia salmolliflora (MoJfeIT) F. Albers, comb. nov.
=:
(Sarcocallion salmoniflorlllll Moffeu. Bothalia 12: 590 ( 1979).
Mansonia spinosa CHerit., Oeran. t. 42 (1792), Type: Jconotype L'Heritier t. 42, 1792. =: (Sarcocaulon l'heritieri Sweet, Haft. Brit. cd. 1: 73 (1826). Monsonia vanderietiae (L. Bolus) F. Albers, comb. nov. ;;;; (Sarcocallioll val1derietiae L. Bolus. S. Afr. Gard. 22: 10 ( 1932).
Acknowledgements I [h ank Dr Ulri ch Mew, MUnster. and an anonymous referee for valuable comments. The studies were funded by the Demsche For3chungsgemeinsl:huft.
References ALBE RS. F. & LOSBERT, D. 1996. The status of the genus San:()L·QulOll (Geraniaceae). XXII SAAB Congress. Stellenbosch. Abstract 36. A LBER S, F. G IBB Y, M. & AUSTMANN. M. 1992. A reapprai sal o r Pelargonilon sect. Liguiaria. Pl. Sysr. Evol. 179: 257- 276. BO ISS IER . E. 1867. Flora Oriental is I. H. Georg. Geneva. CRAIB. C. 1995. The sarcocaulons orSoulhcrn Africa. Hy.trrix I: 1-60. DE CANDOLLE, A.J . [824. Prodorn us syslcmalis naluralis regm vegetabilis. Vol. I. p. 638. TreuttcJ & Wurtz, Paris . DREYER. L.L .. ALBERS. E. VAN DER WALT. J.J.A.. & MAR SCHEWS KI. D.E. [992. Subdivision or Pelargonium sect. Corrllsina (Geraniaceae). PI. Sysr. Evol. 183: 83-97. KERS. L.E. 1968. Contribution towards a revision of Monsonia. Bot. Not. 121: 44-50. KNUTH. R. 19 12. Geraniaceae. In: Dus pnanzenreich. cd. A. Engler. Bd. 4, Vol. 129. Engelmann. Leipzig. LOSSERT, D. 1994. Untersuchungen zur Ontogen ie des Androeceums verschiedener Geraniaceae. M.Sc. thesis. Muenster Uni vers ity. Germany. MARSCHEWSKI. D. 1995. Chemotaxonomischc Untersuchungen an
347
S. Afr. J. Rot. 1996, 62(6) Pclargoniu l1l -Arlcn (Gc ran iaceae) als Beit rag zur Syste malik def Gattung. Ph.D. thes i ~, Muenster University. Germany.
SWEET. R. 1826. Geraniat.:cac. Vol. 4. James Ridgeway, London.
MOFFETT, R.O. 1l)7l). The genus Sllft:owuloll. Bolhlllia 12: 5g 1- 613.
TOULOUMENIDOU, T. 1996. Prolclnmuslcr als taxonomischc Marker von Arten tier GaUu ng Pdargoniulll lGeramat.:cac}. M.Sc. thes is.
PRICE. R.A. & PA LMER, J.D. 1993. Phy logeneti(.; relationships of the Gerani accac and Geran ialcs from rbcL seq ue nce comparisinns . Ann. Mo. hot. Gdll. HO: 661 - 67\.
VENTER H.J.T. [1.)79. A monograph of !vIol/.wnia L. (Geraniaccae). Mt·(/ed. ullltlb. ~Vtl,s;' . Nl'tierilllll/79 . 9: 1- 128.
Muenster University. Germany.
S. Mr. I. Bot. 1996. h2(6): 345-347 BELL. K.L.. HI ATT. H.D. & NILES. W.E. 1979. Seasonal changes in
hiomass allocation in eight winter annuals of the Mojave Desert. 1. fcot. 67 : n 1- 7H7. BENEKE. K .• VAN ROOYEN. M.W. & THERON . G.K. 1992. Fruit polymorphism in ephemeral species of Namaqualand: 6. lntermorphic competition amo ng plants cultivated from d imorphic diaspore s. S. Afr. 1. Yot. Sg: 461--468. CLARK. D.O. & BURK, J.H. 19RO. Resource allocation patterns of two Ca liforma Sonoran Desert ephemera Is. Oet:lI{og;o (Berlin) 46: R6-'J I . CONNOLLY. J. J9H6. On difficulties with rcpi acemenHcnes methodology in mixture ex periments. J. appl. £1.:01. 23: 125- 137.
DE WIT, C.T. 1960. On competition. Ventog LllIulbollwklll1tiigc Ollder(.
6h: 1-82. DURA LI A. T.E. & READER.R.J. IY93 . Docs abundance renect competitive ability?: A test with three prairie grasses. Oikos 68: 82-90 . FIRB ANK, L.G . & WATK INSON, A. R. 1985. On the analysis of competition within two species mixtures of plants. J. oppl. E<:o/. 22: 503 517. FOWLER. N. 1982. Competition and coex istence i n a North Carol ina grassland. J. EC(I/. 70; 77-92. GAUSE, G,F. 1934. The struggle for existe nce_Waverly, Baltimore. GOLDBER G, D.E. & BARTON, A.M. 1992. Patterns and consequences of interspeci fic compe tition in natu ral comm unities: a revIew of field expe riments with plants. Am. Nat. 139: 77 1- 80 I. HALL, R.L. 1974. A naly sis of the nillure interference between plants of different species: I . Concepts and extension of the Dc Wi[ analysis to examine effec ts. AII.~": J. ngric:. Re.'i. 25; 73 9- 747. HARPER, J.L. 1977. Population biology of plants. Academic Press. London. LAURI, H. & COWLING, R.M. 1994. Lottery coexistence models ex tended to plants with disjoint generati ons. J. wg. Sci. 5: 161 - 168. HEW ITT, E.T. 1962. Sand and water cu lture methods used in the study of plan t nutrition. Farnham Royal, Bucks, Commonwealth Agricultura l Bureau. JOLIFFE. P.A .• MINJAS. A.N. & RUNECKLES. V.C. 1984. A reinterpretation of yield relationships in replacement series experiments. J. orf/I. Eco/. 21: 227-243. KEDDY, P.A. 1989. Compelition. Chapman & HalJ. London. MACK, R.N. & HAR PER, J,L. 1977. Interference in dune annuals: Spatial pattern and neighbourhood effects. 1. £<"01. 65: 345-363. MCGILCHRIST. C.A. & TRENBATH. B .R. 1971. A rev ised analySIS of plant competition experiments. Bi(Jmetril.:,t 27: 659-671. MEAD, R. 1979. Competition experiments. Biometric.\' 35: 4 1-54. RoSC H. H. I Y96. Li fe history strategies of Namaqualand pioneer plant spec ies. M.Sc. ui ssenation, University of Pretoria, Pretori a. SHIPLEY, B. & KEDDY, P.A. 1994. Evalu ating the ev idence for competitive hierarchies in plant commun ities. Oikm 69: 340-345. SHMIDA, A. & ELLNER. S.P. 1984. Coexistence of plants with simil ar niches. Vegetario 58: 29- 55. SILVERTOWN, J.W. & LOVETT DOUST, J. 1993 . Introduction to plan t popUlation biology. Blackwell, Oxford. SNAYDON. R.W. 1991. Replacement or addi tive design for competi ti on studies? 1. app l. Er.:ol. 28: 930--946. STEYN . A.G.W.. SM ITH. C.F. & DU TOIT. S.H.C. 1987. Moderne statistiek in die praktyk, 4th cdn. Sigma, Pretoria. TAYLOR, D .R. & AA RS SEN, LW. 1989. On the density dependence of replacement series competition ex periments. J. Et.'ol. 77: 975-988. TRENBATH, B.R. 1974. Biomass productivity of mixtures. Adv, Agron. 26: 177-210. VAN ROOY EN, M .W, 1988. Ekofis iol og iese studies van die efemere van Namakwaland. Ph.D. thesis, Uni versi ty of Pretoria. Pretoria. WILSON, J.B. 1988. ShOal competition and root competition. J. appl. Et.'(J/. 25: 279-296.
or
The taxonomic status of Sarcocauloll (Geraniaceae) F. Albers Institut fOr Botanik , Westfalische -Wilhelms-Unive rsitat. Schlossgarten 3, 0·48 149 Munster , Germany Received J October lYY6; r('viud 2-1 October J99fJ
The circu mscription of Sarcocaulon and Monsonia is reconsidered in view of th e morphological diversity in the closely related genus Pe/argonium. SEM studies of the and roecium ontogeny reveal that there is no reason for maintaining Sarcocaulon and Monsonia as separate genera. The gross morphologica l characte rs currently used to separate the two genera occur also in severa l sections of Pelargonium. Karyologic, ch em otaxonomic and DNA studies also su pport the lumping of the two genera. The necessary taxonomic changes are made. Keywords : Generic Sarcocau/on.
delimitation.
Geraniaceae ,
Mansonia,
De Candolle (1824) descri bed Sarcocllulon as a nl.!w section within the ge nu s M OllS(mia L (Gcraniaceae). However, Sweet ( 1826) excluded Sarcocflll lcm and raisetl it to generic rank. Knuth (1912) used androecium morphology charac ters, apart from growth form characters. as fu rthe r evidence for mai nta ining the two as separate genera. Sarcoc(/ulon has since been di st ingui shed from Monsonia on the basis of its th ick . more or less succulent and often woody stem s and free stamens as opposed to the mo stly herbaceous stem s and basa lly connate stamens in M OlIsoIlia. Moffet! (1979) and Venter (1979) adopted th is c lass ification and presented revisions of Sarcocauioll and MOllsonia respecti vely, maint aining them as separate genera. They al so provi ded historical reviews and nomenclatural changes, and created SI.!Ction s within these genera. Multi disciplinary studies of most of the spec ies in the closel y related ge nus, Pe/argoll illlll, have cast serious doubt on the long-held views on Sarcocauloll and M OIlsonia as two di stinct ge nera. The key characte rs used to separate them occur also in a range of Pelargollillln sections. The differentiation of Monsonia and SarC:OC(lIlJOI! is main ly based on the gross morphology. In cont ras t to the predominantly herbaceous stems of M OllSollia species, those of Sa rcoc(1II1on form thick , more or less woody to succu lent, oflen spi nescent stems. In closely related Pclargol1illlll species, similar differences in growth forms are frequently fou nd in co mparable habitats. Many species of Pelargonillln sec t. Corl(lsill(/ (DC.) Harv. (e.g. Dreyer ef al. 1992) and sect. Otidia ex hibi t similar growth forms and often share the arid habitats wi th species of Sarc:ocaulon. M onsollia and SarCOC(llf/OIl have a similar nower structure but Knuth (1912) observed a difference in the androeci um in selected species of the two genera. He pointed out that the 15 stamens of Monsonia are grouped together and are connate at the base, whereas in Sa rcOC(lu/OII, the 15 stamens an: all free. This was why he maintained Sa rcoc{/uioll and Monsonia as separate genera. SEM stu dies on the ontoge ny of androcce ium develop mellt have demonstrated that there is no diiTerence between Mansonia and Sarc{)cliuloll (Lobbert 1994: Albers & L6bbert 1996). a fac t also noted by Venter (1979).
Studies on non-morphological aspects such as phenolic compou nds (Marschewski 1995), prote in patterns (Tou loumen idou 1996) and a variety of basic chromosome numbers (Monsonia, x = 8. 9. 10. II . 12; SII reoellll/oll , .t = I I ) (A lbers. unpubli shed) support the lumping of the two taxa. Based on rbcL sequence comparisions, Price and Palmer ( 1993) observed that M onsonia and Sarcocaulon an:! either sister genera or congeneric. The dif-
346
S. Afr. J. Bot. 19%.62(6)
ft.:rcnces bl!twl.!cn [he Pe/argonillm natural entities (sections)
Monsonia h errei (L.Bollls) F. Albers. comb. nov.
afC
striking ly larger.
;;;; (Sarcocau/oll herrei L. Bolus. S. Afr. Oard. 22: 10 (1932).
The known chromoso me numbers of the MOllsollja s. sir. s pc ~
des do not support the current (Kcrs 1968) or thl.! former cuncepts (De Candollc 1824; Boissicr 1867; Knuth 1912) of sectional division. The necessary revision of the intragcneric classification of the spedcs hasell on chromosome numbers can be expected in view of the importance of the karyological characters as good taxonomic markers for differentiating sections of PelargOllilllll (e.g. Albers e t al. 1992; Dreyer el a/. 1992). The sect. SarCOC(llI/OIl forms a well-circumscribed taxon within the genus Monsonia. The sect. Sarcoc(lu/oll is distributed mai nl y in the western parts of South Africa (the true winler-rainfaJl area) and Namibia, and one species is also found in southern Ango la. Two species occur in the arid regions of the Eastern Cape Province of South Africa (su mmer-rainfall area) (Moffett 1979; Cra ib 1(95). Th~se species arc we ll adapted to the arid karroid and desert conditions. MOflSonin has a much wider distribution over Africa and into Arabia and India. The simi lari ties in the growth fo rms in species of Sa rcocnu/oll , Mcmsollia and Peim~~ oHillm are most likt:ly a result of parallel evo lution in similar habitats. In the absence of reliable morpholog ical characters fo r separating Sarcocmt/vll from MOllsonia. it is considered unavoidable to resurrect De Candollc's ( 1824) cJassilication. Sarcoc(lltloll (DC) Sweet is therefore rcsunk under MOII.wmia L. Accord in g to Dc Candollc ( 1824), Sarcocauloll species form a secti on of their ow n within Monsonin s.l. The sectional divisions of Sarcocaulol1 created by Moffett (1979) are based only on leaf morphological characters, which are strongly in fluenced by environmental condi ti ons. and are therefore plastic and unreliable. Moffett'S (1979) sectional divisions within SarcoCfmloll are therefore rejected here and the 17 new combinations and accepted species are as follows:
MOllsollia L. sect. Sarcocauloll DC., Prodr. I: 638 (1824) "SarcoC
= Sarcocal/lol! sect. Crell(l{wn Moffett, Bothalia 12: 596 (1979). Type: S. cl'llssiwuie Rehm. Bot. Jahrb. Syst. 67: 271 ( 1935).
= Sa rcncalilon sect. DelltiClilatum Moffett, BothuJia 12: 602 (1979), Type: S. mossamedellse (Welw. ex. Oliv.) Hiem., Cat.
Afr. PI. Wclw. I: 108 (1896). = Sarcocau/oll sect. Mllltifidum Moffett, Bothalia 12: 607 ( 1979). Type: S. l1lultifidul1l E. Mey. ex Knuth, pnanzenr. 4.
129: 312 ( 19 12). Type species: M. spinosa L'Hcrit. 111onsollia camdeboense (Moffett) F. Alhers. comb. nov. ;;;; (Sarcoc:au(oll camdebocnse Moffett. Bothalia 12: 593 (1979). Mansonia ciliata (Moffert) F. Albers. comb. nov. " (Sarcocauloll cifiatum Moffett, Both.lia 12: 600 (1979). Mansonia crassicaule (Rehm) F. Alhers. comb. nov. =:
(Sarcoc(luloJi crassicaule Rehm, Bol. Iahrb. Syst. 67: 271 (1935). M01lS0lliajlavesce1ls (Rehm) F. Albers. comb. nov.
;;; (Sarcoc(lulon f/avescens Rchm. Bot. lahrb. Syst. 67: 271 ( 1935).
MOllsonia inerme (Rehlll) F. Alhers, comb. nov. (Sarcocau/oll il/crme Rehm. Bot. Jahrh. Syst. 67: 269 (1935).
=:
Mansonia marlothii (Engl.) F. Albers, comb. nov. ;;;; (Sarcocau/oll m(lr/olhii Engl., BOL lahrb. Syst. 10: 31 ( 1889). Mansonia mossamedellse WelH'. ex Oliv., FL Trap. Afr. 1: 290 ( 1868). =: (Sarcocau/oll lIlossamedellse (\Velw. ex Oliv.) Hiem, Cat. Afr. PI. Wclw. I: 108 (1896). Mansonia multi/ida (E. Mey. e.\ [Kll uth] F. Albers L. Bal., Flower. PI. Afr. 10: t. 399 (1930). E (S(lrcoc(luloll I1l1tlti{tdlll1l E. Mey. ex Knuth. PJlanzenr. 4. 129: 3 12 (19 12).
MOI/sollia patersollii DC. ; Prodr. I: 638 (1824). ;;;; (Sarcocall /oll patersollii (DC.) G. Don, Gen. Syst. I : 715 (183 1). MonsolJiapeniculilJa (Moffett) F. Albers, comb. nov. =:
(Sarcocallfo ll pellicu/illlllll Motlett, Bot ha1i a 12: 610 ( 1979). Monsonia salmolliflora (MoJfeIT) F. Albers, comb. nov.
=:
(Sarcocallion salmoniflorlllll Moffeu. Bothalia 12: 590 ( 1979).
Mansonia spinosa CHerit., Oeran. t. 42 (1792), Type: Jconotype L'Heritier t. 42, 1792. =: (Sarcocaulon l'heritieri Sweet, Haft. Brit. cd. 1: 73 (1826). Monsonia vanderietiae (L. Bolus) F. Albers, comb. nov. ;;;; (Sarcocallioll val1derietiae L. Bolus. S. Afr. Gard. 22: 10 ( 1932).
Acknowledgements I [h ank Dr Ulri ch Mew, MUnster. and an anonymous referee for valuable comments. The studies were funded by the Demsche For3chungsgemeinsl:huft.
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