Plant Systematics and Evolution

, Volume 191, Issue 1–2, pp 83–104 | Cite as

Merosity in flowers: Definition, origin, and taxonomic significance

  • L. P. Ronse Decraene
  • E. F. Smets


The term merosity stands for the number of parts within whorls of floral organs, leaves, or stems. Trimery is considered to be a basic condition that arose through the cyclisation of a spiral flower. Pentamery is mostly derived from trimery by the repetitive fusion of two different whorls. Dimery is either directly derived from trimery, or through pentamery as an intermediate stage. Tetramery is linked with pentamery and should not be confused with dimery. Possible causes for a change in merosity are the reduction of the number of carpels and zygomorphy in flowers. Derivations of different merosities have important consequences for the arrangement of the androecium (the insertion of stamen whorls, their identifications, and their number). It is concluded that two main groups can be identified within the angiosperms: magnolialean and monocotyledonean taxa are mostly trimerous or dimerous; non-magnolialean dicots are mostly pentamerous or tetramerous.

Key words

Angiosperms androecium Merosity phyllotaxis pseudowhorl zygomorphy 


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  1. Armstrong, J. E., 1988: The suppression and loss of androecial primordia and their affect on corolla form inScrophulariaceae. — Amer. J. Bot.75, Suppl., Abstr.: 17–18.Google Scholar
  2. Batenburg, L.H., Moeliono, B.M., 1982: Oligomery and vasculature in the androecium ofMollugo nudicaulis Lam. (Molluginaceae). — Acta Bot. Neerl.31: 215–220.Google Scholar
  3. Bersillon, G., 1955: Recherches sur les Papavéracées. Contribution à l'étude du développement des Dicotylédones herbacées. — Ann. Sci. Nat. Bot.16: 225–443.Google Scholar
  4. Carlquist, S., 1992a: Wood anatomy and stem ofChloranthus; summary of wood anatomy ofChloranthaceae, with comments on relationships, vessellessness, and the origin of Monocotyledons. — IAWA Bull. n.s.13: 3–16.Google Scholar
  5. —, 1992b: Wood anatomy ofChloranthaceae: a summary, with comments on origin of Monocotyledons. — Amer. J. Bot.79, Suppl., Abstr.: 137.Google Scholar
  6. Cejp, K., 1925: Beitrag zur vergleichenden Morphologie der dimerischen Blüten. — Beih. Bot. Centralbl.41: 128–164.Google Scholar
  7. Chatin, A., 1873: Sur l'organogénie de l'androcée des Labiées, des Globulariées et des Scrofularinées. — Bull. Soc. Bot. France20: 41–45.Google Scholar
  8. Cronquist, A., 1981: An integrated system of classification of flowering plants. — New York: Columbia University Press.Google Scholar
  9. Dahlgren, R., 1983: General aspects of angiosperm evolution and macrosystematics. — Nordic J. Bot.3: 119–149.Google Scholar
  10. —, 1984: The orderMyrtales: circumscription, variation and relationships. — Ann. Missouri Bot. Gard.71: 633–699.Google Scholar
  11. —, 1982: The monocotyledons — a comparative study. — London: Academic Press.Google Scholar
  12. —, —, 1985: The families of the monocotyledons — structure, evolution and taxonomy. — Berlin: Springer.Google Scholar
  13. Ehrendorfer, F., 1977: New ideas about the early differentiation of angiosperms. — Pl. Syst. Evol. Suppl. 1: 227–234.Google Scholar
  14. Eichler, A. W., 1875–1878: Blüthendiagramme I and II. — Leipzig: Engelmann.Google Scholar
  15. Endress, P. K., 1987: Floral phyllotaxis and floral evolution. — Bot. Jahrb. Syst.108: 417–438.Google Scholar
  16. —, 1990: Patterns of floral construction in ontogeny and phylogeny. — Biol. J. Linn. Soc.39: 153–175.Google Scholar
  17. —, 1992: Evolution and floral diversity: the phylogenetic surroundings ofArabidopsis andAntirrhinum. — Int. J. Pl. Sci.153: s106-s122.Google Scholar
  18. Erbar, C., Leins, P., 1981: Zur Spirale in Magnolien-Blüten. — Beitr. Biol. Pfl.56: 225–241.Google Scholar
  19. —, —, 1983: Zur Sequenz von Blütenorganen bei einigen Magnoliiden. — Bot. Jahrb. Syst.103: 433–449.Google Scholar
  20. Friedrich, H.-C., 1956: Studien über die natürliche Verwandtschaft derPlumbaginales undCentrospermae. — Phyton6: 220–263.Google Scholar
  21. Galle, P., 1977: Untersuchungen zur Blütenentwicklung der Polygonaceen. — Bot. Jahrb. Syst.98: 449–489.Google Scholar
  22. Geitler, L., 1929: Zur Morphologie der Blüten von Polygonum. — Österr. Bot. Z.78: 229–241.Google Scholar
  23. Gross, H., 1913: Beiträge zur Kenntnis der Polygonaceen. — Bot. Jahrb. Syst.49: 234–339.Google Scholar
  24. Guédès, M., 1967: The cruciferous flower. — Adv. Front. Pl. Sci.18: 169–218.Google Scholar
  25. Gupta, D., Singh, V., 1983: Floral organogenesis ofRanunculus sceleratus L. — Proc. Indian Natl. Sci. Acad.B49: 273–277.Google Scholar
  26. Hiepko, P., 1965: Vergleichend morphologische und entwicklungsgeschichtliche Untersuchungen über das Perianth bei denPolycarpicae. — Bot. Jahrb. Syst.84: 359–508.Google Scholar
  27. Hirmer, M., 1918: Beiträge zur Morphologie polyandrischer Blüten. — Flora110: 140–192.Google Scholar
  28. Hofmann, U., 1973: Centrospermen-Studien 6: Morphologische Untersuchungen zur Umgrenzung und Gliederung der Aizoaceen. — Bot. Jahrb. Syst.93: 247–324.Google Scholar
  29. —, 1990:Morina L. undTriplostegia Wall. ex DC. im Vergleich mitValerianaceae undDipsacaceae. — Bot. Jahrb. Syst.111: 499–553.Google Scholar
  30. Huber, H., 1977: The treatment of the monocotyledons in an evolutionary system of classification. — Pl. Syst. Evol. Suppl.1: 285–298.Google Scholar
  31. —, 1982: Die zweikeimblättrigen Gehölze im System der Angiospermen. — Mitt. Bot. Staatssamml. München18: 59–78.Google Scholar
  32. Karrer, A. B., 1991: Blütenentwicklung und systematische Stellung derPapaveraceae undCapparaceae. — Doctoral Dissertation University of Zürich.Google Scholar
  33. Kubitzki, K., 1969: Monographie der Hernandiaceen. — Bot. Jahrb. Syst.89: 78–209.Google Scholar
  34. —, 1973: Probleme der Großsystematik der Blütenpflanzen. — Ber. Deutsch. Bot. Ges.85: 259–277.Google Scholar
  35. —, 1987: Origin and significance of trimerous flowers. — Taxon36: 21–28.Google Scholar
  36. Lacroix, C., Sattler, R., 1988: Phyllotaxis theories and tepal-stamen superposition inBasella rubra. — Amer. J. Bot.75: 906–917.Google Scholar
  37. Leins, P., 1964: Die frühe Blütenentwicklung vonHypericum hookerianum Wight etArn. undH. aegypticum L. — Ber. Deutsch. Bot. Ges.77: 112–123.Google Scholar
  38. —, 1967: Die frühe Blütenentwicklung vonAegle marmelos (Rutaceae). — Ber. Deutsch. Bot. Ges.80: 320–325.Google Scholar
  39. —, 1971: Das Androeceum der Dikotylen. — Ber. Deutsch. Bot. Ges.84: 191–193.Google Scholar
  40. —, 1991: Entwicklungsmuster in Blüten und ihre mutmaßlichen phylogenetischen Zusammenhänge. — Biol. Unserer Zeit21: 197–204.Google Scholar
  41. —, 1979: Entwicklungsgeschichtliche Untersuchungen anCapparis-Blüten. — Bot. Jahrb. Syst.100: 542–554.Google Scholar
  42. Lyndon, R. F., 1978: Flower development inSilene: morphology and sequence of initiation of primordia. — Ann. Bot.42: 1343–1348.Google Scholar
  43. Mayr, B., 1969: Ontogenetische Studien anMyrtales-Blüten. — Bot. Jahrb. Syst.89: 210–271.Google Scholar
  44. Meier-Weniger, E., 1977: Die Morphogenese der Blüte vonPedicularis recutita L. (Scrophulariaceae). — Ber. Deutsch. Bot. Ges.90: 67–75.Google Scholar
  45. Merxmüller, H., Leins, P., 1966: Zum Blütenbau derBrassicaceae. — Ber. Deutsch. Bot. Ges.79: 250–252.Google Scholar
  46. —, —, 1967: Die Verwandtschaftsbeziehungen der Kreuzblütler und Mohngewächse. — Bot. Jahrb. Syst.86: 113–129.Google Scholar
  47. Mione, T., Bogle, A. L., 1990: Comparative ontogeny of the inflorescence and flower ofHamamelis virginiana andLoropetalum chinense (Hamamelidaceae). — Amer. J. Bot.77: 77–91.Google Scholar
  48. Nishino, E., 1988: Early floral organogenesis inTripetaleia (Ericaceae). — InLeins, P., Tucker, S. C., Endress, P. K., (Eds): Aspects of floral development, pp. 181–190. — Berlin: Cramer.Google Scholar
  49. Payer, J. B., 1857: Traité d'organogénie comparée de la fleur. — Paris: Masson.Google Scholar
  50. Radford, A. E., Dickison, W. C., Masset, J. R., Bell, C. R., 1974: Vascular plant systematics. — New York: Harper & Row.Google Scholar
  51. Ramirez-Domenech, J. I., Tucker, S. C., 1989: Phylogenetic implications of inflorescence and floral ontogeny ofMimosa strigillosa. — Amer. J. Bot.76: 1583–1593.Google Scholar
  52. Robyns, W., 1972: Outline of a new system of orders and families ofSympetalae. — Bull. Jard. Bot. Natl. Belg.42: 363–372.Google Scholar
  53. Roels, P., 1993: Lengtepolymorfisme van chloroplast-DNA restrictiefragmenten en bloemontogenie in deDipsacales. — Unpubl. thesis: Katholieke Universiteit Leuven.Google Scholar
  54. Ronse Decraene, L. P., 1989: The flower ofKoenigia islandica L. (Polygonaceae): an interpretation. — Watsonia17: 419–423.Google Scholar
  55. - 1992: The androecium of theMagnoliophytina: characterisation and systematic importance. Unpubl. Doctorate thesis: Katholieke Universiteit Leuven.Google Scholar
  56. —, 1988: Generic limits inPolygonum and related genera (Polygonaceae) on the basis of floral characters. — Bot. J. Linn. Soc.98: 321–371.Google Scholar
  57. —, 1987: The distribution and the systematic relevance of the androecial characters oligomery and polymery in theMagnoliophytina. — Nordic J. Bot.7: 239–253.Google Scholar
  58. —, —, 1990a: The floral development ofPopowia whitei (Annonaceae). — Nordic J. Bot.10: 411–420 [correction in Nordic J. Bot.11: 420, 1991].Google Scholar
  59. —, —, 1990b: The systematic relationship betweenBegoniaceae andPapaveraceae: a comparative study of their floral development. — Bull. Jard. Bot. Natl. Belg.60: 229–273.Google Scholar
  60. —, —, 1991a: Androecium and floral nectaries ofHarungana madagascariensis (Clusiaceae). — Pl. Syst. Evol.178: 179–194.Google Scholar
  61. —, —, 1991b: The floral ontogeny of some members of thePhytolaccaceae (subfamilyRivinoideae) with a discussion of the evolution of the androecium in theRivinoideae. — Biol. Jaarb. Dodonaea59: 77–99.Google Scholar
  62. —, —, 1992: Complex polyandry in theMagnoliatae: definition, distribution and systematic value. — Nordic J. Bot.12: 621–649.Google Scholar
  63. - - 1993: The distribution and systematic relevance of the androecial character Polymery. — Bot. J. Linn. Soc.113 (in press).Google Scholar
  64. Salisbury, E. J., 1919: Variation inEranthis hyemalis, Ficaria verna, and other members of theRanunculaceae, with special reference to trimery and the origin of the perianth. — Ann. Bot.33: 47–79.Google Scholar
  65. Sands, M. J. S., 1973: New aspects of the floral vascular anatomy in some members of the orderRhoeadales sensuHutch. — Kew Bull.28: 211–256.Google Scholar
  66. Sattler, R., 1973: Organogenesis of flowers, a photograpic text-atlas. — Toronto, Buffalo: University of Toronto Press.Google Scholar
  67. —, 1982: Floral development ofBougainvillea spectabilis Willd.,Boerhaavia diffusa L. andMirabilis jalapa L. (Nyctaginaceae). — Bot. J. Linn. Soc.84: 161–182.Google Scholar
  68. Schmid, R., Carlquist, S., Hufford, L. D., Webster, G. L., 1984: Systematic anatomy ofOceanopapaver, a monotypic genus of theCapparaceae from New Caledonia. — Bot. J. Linn. Soc.89: 119–152.Google Scholar
  69. Schöffel, K., 1932: Untersuchungen über den Blütenbau der Ranunculaceen. — Planta17: 315–371.Google Scholar
  70. Singh, V., 1979: Early floral development inDigitalis purpurea. — Phytomorphology29: 239–245.Google Scholar
  71. Smyth, D. R., Bowman, J. L., Meyerowitz, E. M., 1990: Early flower development inArabidopsis. — Pl. Cell2: 755–767.Google Scholar
  72. Sterk, A. A., 1970: Reduction of the androecium inSpergularia marina (Caryophyllaceae). — Acta Bot. Neerl.19: 488–494.Google Scholar
  73. Stoudt, H. N., 1941: The floral morphology of some of theCapparidaceae. — Amer. J. Bot.28: 604–675.Google Scholar
  74. Takhtajan, A., 1991: Evolutionary trends in flowering plants. — New York: Columbia University Press.Google Scholar
  75. Taylor, D. W., Hickey, L. J., 1992: Phylogenetic evidence for the herbaceous origin of angiosperms. — Pl. Syst. Evol.180: 137–156.Google Scholar
  76. Tepfer, S. S., 1953: Floral anatomy and ontogeny inAquilegia formosa var.truncata andRanunculus repens. — Univ. Calif. Publ. Bot.25: 513–648.Google Scholar
  77. Tucker, S. C., 1984: Unidirectional organ initiation in leguminous flowers. — Amer. J. Bot.71: 1139–1148.Google Scholar
  78. —, 1988: Dioecy inBauhinia resulting from organ suppression. — Amer. J. Bot.75: 1584–1597.Google Scholar
  79. —, 1989: Overlapping organ initiation and common primordia in flowers ofPisum sativum (Leguminosae: Papilionoideae). — Amer. J. Bot.76: 714–729.Google Scholar
  80. Uhl, N. W., Moore, H. E., 1980: Androecial development in six polyandrous genera representing five major groups of palms. — Ann. Bot.45: 57–75.Google Scholar
  81. Van Heel, W. A., 1992: Floral morphology ofStemonaceae andPentastemonaceae. — Blumea36: 481–499.Google Scholar
  82. Van Steenis, C. G. G. J., 1982:Pentastemona, a new 5-merous genus of Monocotyledons from North Sumatra (Stemonaceae). — Blumea28: 151–163.Google Scholar
  83. Vanvinckenroye, P., Cresens, E., Ronse Decraene, L. P., Smets, E., 1993: A comparative floral developmental study inPisonia, Bougainvillea andMirabilis (Nyctaginaceae) with special emphasis on the gynoecium and the floral nectaries. — Bull. Jard. Bot. Natl. Belg.62: 69–96.Google Scholar
  84. Vautier, S., 1949: La vascularisation florale chez les Polygonacées. — Candollea12: 219–343.Google Scholar
  85. Volgin, S. A., 1988: Vergleichende Morphologie und Gefäßbündelanatomie der Blüte bei denRivinoideae (Phytolaccaceae). — Flora181: 325–337.Google Scholar
  86. Wagenitz, G., 1992: TheAsteridae: evolution of a concept and its present status. — Ann. Missouri Bot. Gard.79: 209–217.Google Scholar
  87. Walter, H., 1906: Die Diagramme der Phytolaccaceen. — Bot. Jahrb. Syst.37, Beibl. 85: 1–57.Google Scholar
  88. Willis, J. C., 1966: A dictionary of the flowering plants and ferns. 7th edn. — Cambridge: Cambridge University Press.Google Scholar

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • L. P. Ronse Decraene
    • 1
  • E. F. Smets
    • 1
  1. 1.Laboratory of Systematics, Botanical InstituteKatholieke Universiteit LeuvenHeverlee (Leuven)Belgium

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