Floral Biology pp 191-216 | Cite as

The Ecology of Geitonogamous Pollination

  • Allison A. Snow
  • Timothy P. Spira
  • Rachel Simpson
  • Robert A. Klips


Working as a natural historian in the 1700s, C.K. Sprengel wrote a pioneering book demonstrating that many hermaphroditic species require pollinator visits in order to produce seed (see Chapters 1 and 2). He did not provide a scientific explanation as to why cross-pollination is important, but in the next century Darwin, H. and F. Müller, and others proposed that various outcrossing mechanisms have evolved to avoid selfing and the consequences of inbreeding (Darwin, 1876; see Baker, 1983). Darwin also recognized that the potential for selfing is greatest in species with massive floral displays because having many flowers promotes the transfer of self-pollen to other flowers on the same genetic individual (geitonogamy). Following Darwin’s lead, many authors have suggested that the avoidance of selfing has been a major factor in the evolution of traits such as dioecy, self-incompatibility, monoecy, temporal separation of male and female organs (dichogamy), spatial separation of anthers and stigmas within flowers (herkogamy), and having few open flowers per day (see reviews by Arroyo, 1976; Lloyd, 1979; Bawa and Beach, 1981; Willson, 1983; Wyatt, 1983; Richards, 1986; Charlesworth and Charlesworth, 1987; Thomson and Brunet, 1990; de Jong, et al., 1992a; Harder and Barrett 1995; Hodges, 1995; also see Chapters 6, 8, and 14).


Pollen Carryover Flower Number Floral Display Selfing Rate Central Plant 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Ågren, J. and D.W. Schemske. 1993. Outcrossing rate and inbreeding depression in two annual monoecious herbs, Begonia hirsuta and B. semiovata. Evolution, 47: 125–135.CrossRefGoogle Scholar
  2. Aizen, M.A. 1993. Self-pollination shortens flower lifespan in Portulaca umbraticola H.B.K. (Portulacaceae). Int. J. Plant Sci., 154: 412–415.CrossRefGoogle Scholar
  3. Aizen, M.A., K.B. Searcy, and D.L. Mulcahy. 1990. Among- and within-flower comparisons of pollen-tube growth following self- and cross-pollinations. Am. J. Bot., 77: 671–676.CrossRefGoogle Scholar
  4. Alexander, M.P. 1969. Differential staining of aborted and nonaborted pollen. Stain Technol., 44: 117–122.PubMedGoogle Scholar
  5. Anderson, G.J. and D. Symon. 1988. Insect foragers on Solanum flowers in Australia. Ann. Mo. Bot. Gard., 75: 842–852.CrossRefGoogle Scholar
  6. Arroyo, M.T.K. 1976. Geitonogamy in animal pollinated tropical angiosperms: A stimulus for the evolution of self-incompatibility. Taxon, 25: 543–548.CrossRefGoogle Scholar
  7. Augspurger, C.K. 1980. Mass-flowering in a tropical shrub (Hybanthus prunifolius): Influence on pollinator attraction and movement. Evolution, 34: 475–488.CrossRefGoogle Scholar
  8. Baker, H.G. 1983. An outline of the history of anthecology, or pollination biology. In Pollination Biology (L. Real, ed.), Academic Press, New York, pp. 7–30.Google Scholar
  9. Barrett, S.C.H. and D. Charlesworth. 1991. Effects of a change in the level of inbreeding on the genetic load. Nature, 352: 522–524.PubMedCrossRefGoogle Scholar
  10. Barrett, S.C.H. and J.R. Kohn. 1992. Genetic and evolutionary consequences of small population size in plants: Implications for conservation. In Genetics and Conservation of Rare Plants (D.A. Falk and K.E. Holsinger, eds.), Oxford Univ. Press, New York, pp. 3–30.Google Scholar
  11. Barrett, S.C.H., J.R. Kohn, and M.B. Cruzan. 1992. Experimental studies of mating system evolution: The marriage of marker genes and floral biology. In Ecology and Evolution of Plant Reproduction (R. Wyatt, ed.), Chapman & Hall, New York, pp. 192–230.Google Scholar
  12. Barrett, S.C.H., L.D. Harder, and W.W. Cole. 1994. Effects of flower number and position on self-fertilization in experimental populations of Eichhornia paniculata (Pontederiaceae). Func. Ecol., 8: 526–535.CrossRefGoogle Scholar
  13. Bateman, A.J. 1956. Cryptic self-incompatibility in the wallflower: Cheiranthus chieri L. Heredity, 10: 257–261.CrossRefGoogle Scholar
  14. Bawa, K.S. and J.H. Beach. 1981. Evolution of sexual systems in flowering plants. Ann. Missouri Bot. Gard., 68: 254–274.CrossRefGoogle Scholar
  15. Beattie, A.J. 1976. Plant dispersion, pollination and gene flow in Viola. Oecologia, 25: 291–300.CrossRefGoogle Scholar
  16. Becerra, J. and D.G. Lloyd. 1992. Competition-dependent abscission of self-pollinated flowers of Phormium tenax (Agavaceae): A second action of self-incompatibility at the whole flower level. Evolution, 46: 458–469.CrossRefGoogle Scholar
  17. Bertin, R.I. 1993. Incidence of monoecy and dichogamy in relation to self-fertilization in angiosperms. Am. J. Bot., 80: 557–560.CrossRefGoogle Scholar
  18. Bertin, R.I. and C.M. Newman. 1993. Dichogamy in angiosperms. Bot. Rev., 59: 112–152.CrossRefGoogle Scholar
  19. Bertin, R.I. and M. Sullivan. 1988. Pollen interference and cryptic self-incompatibility in Campsis radicans. Am. J. Bot., 75: 1140–1147.CrossRefGoogle Scholar
  20. Best, L.S. and P. Bierzychudek. 1982. Pollinator foraging on foxglove (Digitalis purpurea): A test of a new model. Evolution, 36: 70–79.CrossRefGoogle Scholar
  21. Bierzychudek, P. 1982. The demography of jack-in-the-pulpit, a forest perennial that changes sex. Ecol. Monogr., 52: 335–351.CrossRefGoogle Scholar
  22. Bowman, R.N. 1987. Cryptic self-incompatibility and the breeding system of Clarkia unguiculata Lindl. (Onagraceae). Am. J. Bot., 74: 471–486.CrossRefGoogle Scholar
  23. Brown, A.D.H. and R.W. Allard. 1970. Estimation of the mating system in open-pollinated maize populations using isozyme polymorphisms. Genetics, 66: 133–145.PubMedGoogle Scholar
  24. Broyles, S.D. and R. Wyatt. 1993. The consequences of self-pollination in Asclepias exaltata, a self-incompatible milkweed. Am. J. Bot., 80: 41–44.CrossRefGoogle Scholar
  25. Carpenter, F.L. 1976. Plant-pollinator interactions in Hawaii: Pollination energetics of Metrosideros collina (Myrtaceae). Ecology, 57: 1125–1144.CrossRefGoogle Scholar
  26. Casper, B.B., L.S. Sayigh, and S.S. Lee. 1988. Demonstration of cryptic incompatibility in distylous Amsinckia douglasiana. Evolution, 42: 248–253.CrossRefGoogle Scholar
  27. Charlesworth, D. and B. Charlesworth. 1987. Inbreeding depression and its evolutionary consequences. Ann. Rev. Ecol. Syst., 18: 237–268.CrossRefGoogle Scholar
  28. Clegg, M.T. 1980. Measuring plant mating systems. Bioscience, 30: 814–818.CrossRefGoogle Scholar
  29. Crawford, T.J. 1984. What is a population? In Evolutionary Ecology (B. Shorrocks, ed.), 23rd Symposium British Ecological Society, Blackwell Scientific, London, pp. 135–173.Google Scholar
  30. Cruden, R.W. 1988. Temporal dioecism: Systematic breadth, associated traits, and temporal patterns. Bot. Gaz., 149: 1–15.CrossRefGoogle Scholar
  31. Cruden, R.W. and S.M. Hermann-Parker. 1977. Temporal dioecism: An alternative to dioecism? Evolution, 31: 863–866.CrossRefGoogle Scholar
  32. Cruzan, M.B. and S.C.H. Barrett. 1993. Contribution of cryptic incompatibility to the mating system of Eichhornia paniculata (Pontederiaceae). Evolution, 47: 925–934.CrossRefGoogle Scholar
  33. Cruzan, M.B., J.L. Hamrick, M.L. Arnold, and B.D. Bennett. 1994. Mating system variation in hybridizing irises: Effects of phenology and floral densities on family outcrossing rates. Heredity, 72: 95–105.CrossRefGoogle Scholar
  34. Darwin, C. 1876. The Effects of Cross and Self Fertilisation in the Vegetable Kingdom. Murray, London.Google Scholar
  35. Denti, D. and D.J. Schoen. 1988. Self-fertilization rates in white spruce: Effect of pollen and seed production. J. Hered., 79: 284–288.Google Scholar
  36. Dudash, M.R. 1990. Relative fitness of self and outcrossed progeny in a self-compatible, protandrous species, Sabatia angularis L. (Gentianaceae): A comparison in three environments. Evolution, 44: 1129–1139.CrossRefGoogle Scholar
  37. Dudash, M.R. 1991. Plant size effects on female and male function in hermaphroditic Sabatia angularis (Gentianaceae). Ecology, 72: 1003–1012.CrossRefGoogle Scholar
  38. Ellstrand, N., A.M. Torres, and D.A. Levin. 1978. Density and the rate of apparent outcrossing in Helianthus annuus. Syst. Bot., 3: 403–407.CrossRefGoogle Scholar
  39. Epperson, B.K. and M.T. Clegg. 1987. First-pollination primacy and pollen selection in morning glory, Ipomoea purpurea. Heredity, 58: 5–14.CrossRefGoogle Scholar
  40. Feinsinger, P. and W.H. Busby. 1987. Pollen carryover: Experimental comparisons between morphs of Palicourea lasiorrachis (Rubiaceae), a distylous, bird-pollinated, tropical treelet. Oecologia, 73: 231–235.CrossRefGoogle Scholar
  41. Flores, S.I. 1990. Reproductive Biology of Ludwigia peploides peploides and L. peploides glabrescens. Ph.D. diss., Univ. Chicago.Google Scholar
  42. Frankie, G.W., P.A. Opler, and K.S. Bawa. 1976. Foraging behavior of solitary bees: Implications for outcrossing of a neotropical forest tree species. J. Ecol., 64: 1049–1057.CrossRefGoogle Scholar
  43. Galen, C. 1985. Regulation of seed set in Polemonium viscosum: Floral scents, pollination, and resources. Ecology, 66: 792–797.CrossRefGoogle Scholar
  44. Galen, C. and R.C. Plowright. 1985. The effects of nectar level and flower development on pollen carryover in inflorescences of fire weed (Epilobium angustifolium) (Onagraceae). Can. J. Bot., 63: 488–491.CrossRefGoogle Scholar
  45. Galen, C., T. Gregory, and L.F. Galloway. 1989. Costs of self-pollination in a self-incompatible plant, Polemonium viscosum. Am. J. Bot., 76: 1675–1680.CrossRefGoogle Scholar
  46. Geber, M. A. 1985. The relationship of plant size to self-pollination in Mertensia ciliata. Ecology, 66: 762–772.CrossRefGoogle Scholar
  47. Gleeson, S.K. 1982. Heterodichogamy in walnuts: Inheritance and stable ratios. Evolution, 36: 892–902.CrossRefGoogle Scholar
  48. Handel, S.N. 1985. The intrusion of clonal growth patterns on plant breeding systems. Am. Nat., 125: 367–384.CrossRefGoogle Scholar
  49. Harder, L.D., and S.C.H. Barrett. 1995. Mating costs of large floral displays in hermaphrodite plants. Nature, 373: 512–514.CrossRefGoogle Scholar
  50. Heinrich, B. 1979. Resource heterogeneity and patterns of movement in foraging bumble bees. Oecologia, 40: 235–245.CrossRefGoogle Scholar
  51. Hessing, M.B. 1988. Geitonogamous pollination and its consequences in Geranium caespitosum. Am. J. Bot., 75: 1324–1333.CrossRefGoogle Scholar
  52. Hodges, S.A. 1995. The influence of nectar production on hawkmoth behavior, self pollination, and seed production in Mirabilis multiflora (Nyetaginaceae). Amer. J. Botany, 82: 197–204.CrossRefGoogle Scholar
  53. Holsinger, K.E., M.W. Feldman, and F.B. Christiansen. 1984. The evolution of self-fertilization in plants: A population genetic model. Am. Nat., 124: 446–453.CrossRefGoogle Scholar
  54. Holtsford, T.P. and N.C. Ellstrand. 1990. Inbreeding effects in Clarkia tembloriensis (Onagraceae) populations with different natural outcrossing rates. Evolution, 44: 2031–2046.CrossRefGoogle Scholar
  55. Johnston, M.O. 1993. Tests of two hypotheses concerning pollen competition in a self-compatible, long-styled species (Lobelia cardinalis: Lobeliaceae). Am. J. Bot., 80: 1400–1406.CrossRefGoogle Scholar
  56. de Jong, T.J., P.G.L. Klinkhamer, and M.J. van Staalduinen. 1992a. The consequences of pollination biology for selection of mass or extended blooming. Func. Ecol., 6: 606–615.CrossRefGoogle Scholar
  57. de Jong, T.J., N.M. Waser, and P.G.L. Klinkhamer. 1993. Geitonogamy: The neglected side of selfing. Trends Ecol. & Evol., 8: 321–325.CrossRefGoogle Scholar
  58. de Jong, T.J., N.M. Waser, M.V. Price, and R.M. Ring. 1992b. Plant size, geitonogamy and seed set in Ipomopsis aggregata. Oecologia, 89: 310–315.Google Scholar
  59. Kadmon, R. and A. Shmida. 1992. Departure rules used by bees foraging for nectar: A field test. Evol. Ecol., 6: 142–151.CrossRefGoogle Scholar
  60. Kahn, A.P. and D.H. Morse. 1991. Pollen germination and fertilization in self and cross-pollinated common milkweed, Asclepias syriaca. Am. Midi. Nat., 126: 61–67.CrossRefGoogle Scholar
  61. Klinkhamer, P.G.L. and T.J. de Jong. 1993. Attractiveness to pollinators: A plant’s dilemma. Oikos, 66: 180–184.CrossRefGoogle Scholar
  62. Klinkhamer, P.G.L., T.J. de Jong, and G. DeBruyn. 1989. Plant size and pollinator visitation in Cynoglossum officinale. Oikos, 54: 201–204.CrossRefGoogle Scholar
  63. Leclerc-Potvin, C. and K. Ritland. 1993. Modes of self-fertilization in Mimulus guttatus (Scrophulariaceae): A field experiment. Am. J. Bot., 81: 199–205.CrossRefGoogle Scholar
  64. Lertzmann, K.P. and C.L. Gass. 1983. Alternative models of pollen transfer. In Handbook of Experimental Pollination Biology (C.E. Jones and R.J. Little, eds.), Scientific and Academic Editions, New York, pp. 474–489.Google Scholar
  65. Levin, D.A. 1991. The effect of inbreeding on seed survivorship in Phlox. Evolution, 45: 1047–1049.CrossRefGoogle Scholar
  66. Lloyd, D.G. 1979. Some reproductive factors affecting the selection of self-fertilization in plants. Am. Nat., 113: 67–79.CrossRefGoogle Scholar
  67. Lloyd, D.G. 1992. Self- and cross-fertilization in plants. II. The selection of self-fertilization. Int. J. Plant Sci., 153: 370–380.CrossRefGoogle Scholar
  68. Lloyd, D.G. and D.J. Schoen. 1992. Self- and cross-fertilization in plants. I. Functional dimensions. Int. J. Plant Sci., 153: 358–369.CrossRefGoogle Scholar
  69. Lloyd, D.G. and C.J. Webb. 1986. The avoidance of interference between the presentation of pollen and stigmas in angiosperms. I. Dichogamy. New Zeal. J. Bot., 24: 134–162.Google Scholar
  70. McDade, L. A. 1986. Protandry, synchronized flowering and sequential phenotypic unisexuality in neotropical Pentagonia macrophylla (Rubiaceae). Oecologia, 68: 218–223.CrossRefGoogle Scholar
  71. Montaivo, A.M. 1992. Relative success of self and outcross pollen comparing mixed-and single-donor pollinations in Aquilegia caerulea. Evolution, 46: 1181–1198.CrossRefGoogle Scholar
  72. Morgan, M.J. and S.C.H. Barrett. 1990. Outcrossing rates and correlated mating within a population of Eichhornia paniculata (Pontederiaceae). Heredity, 64: 271–280.CrossRefGoogle Scholar
  73. Morris, W.F., M.V. Price, N.M. Waser, J.D. Thomson, B. Thomson, and D.A. Stratton. 1994. Systematic increase in pollen carryover and its consequences for geitonogamy in plant populations. Oikos. 71: 431–440.CrossRefGoogle Scholar
  74. Morse, D. 1994. The role of self-pollen in the female reproductive success of common milkweed (Asclepias syriaca, Asclepiadaceae). Am. J. Bot., 81: 322–330.CrossRefGoogle Scholar
  75. Motten, A.F. and J. Antonovics. 1992. Determinants of outcrossing rate in a predominantly self-fertilizing weed, Datura stramonium (Solanaceae). Am. J. Bot., 79: 419–427.CrossRefGoogle Scholar
  76. Murawski, D.A. and J.L. Hamrick. 1991. The effect of density of flowering individuals on the mating system of nine tropical tree species. Heredity, 67: 167–174.CrossRefGoogle Scholar
  77. Murawski, D.A., J.L. Hamrick, S.P. Hubbell, and R.B. Foster. 1990. Mating system of two Bombacaceous trees of a neotropical moist forest. Oecologia, 82: 501–506.CrossRefGoogle Scholar
  78. Nilsson, L.A., E. Rabakonandrianina, and B. Pettersson. 1993. Exact tracking of pollen and mating in plants. Nature, 360: 666–668.CrossRefGoogle Scholar
  79. Peakall, R. 1989. A new technique for monitoring pollen flow in orchids. Oecologia, 79: 361–365.CrossRefGoogle Scholar
  80. Pleasants, J.M. 1991. Evidence for short-distance dispersal of pollinia in Asclepias syriaca L. Func. Ecol., 5: 75–82.CrossRefGoogle Scholar
  81. Pleasants, J.M. and M. Zimmerman. 1990. The effect of inflorescence size on pollinator visitation of Delphinium nelsonii and Aconitum columbianum. Collect. Bot. (Barcelona), 19: 21–39.CrossRefGoogle Scholar
  82. Pyke, G.H. 1978a. Optimal foraging in bumble bees and coevolution with their plants. Oecologia, 36: 281–293.CrossRefGoogle Scholar
  83. Pyke, G.H. 1978b. Optimal foraging in hummingbirds: Testing the marginal value theorem. Am. Zool., 18: 739–752.Google Scholar
  84. Richards, A.J. 1986. Plant Breeding Systems. George Allen and Unwin, London.Google Scholar
  85. Ritland, K. 1990. A series of FORTRAN computer programs for estimating plant mating systems. J. Hered., 81: 235–237.Google Scholar
  86. Ritland, K. and Y.A. El-Kassaby. 1985. The nature of inbreeding in a seed orchard of Douglas fir as shown by an efficient multilocus model. Theor. Appl. Genet., 71: 375–384.CrossRefGoogle Scholar
  87. Ritland, K. and S. Jain. 1981. A model for the estimation of outcrossing rate and gene frequencies using n independent loci. Heredity, 47: 35–52.CrossRefGoogle Scholar
  88. Robertson, A.W. 1992. The relationship between floral display size, pollen carryover and geitonogamy in Myosotis colensoi (Kirk) Macbride (Boraginaceae). Biol. J. Linn. Soc., 46: 333–349.CrossRefGoogle Scholar
  89. Schemske, D.W. 1980. Floral ecology and hummingbird pollination of Combretumfarinosum in Costa Rica. Biotropica, 12: 169–181.CrossRefGoogle Scholar
  90. Schemske, D.W. 1983. Breeding system and habitat effects on fitness components in three neotropical Costus (Zingiberaceae). Evolution, 37: 523–539.CrossRefGoogle Scholar
  91. Schlessman, M.A., P.P. Lowry, and D.G. Lloyd. 1990. Functional dioecism in the New Caledonian endemic Polyscias pancheri (Araliaceae). Biotropica, 22: 133–139.CrossRefGoogle Scholar
  92. Schmid-Hempel, P. and B. Speiser. 1988. Effects of inflorescence size on pollination in Epilobium angustifolium. Oikos, 53: 98–104.CrossRefGoogle Scholar
  93. Schmitt, J. 1980. Pollinator foraging behavior and gene dispersal in Senecio (Compositae). Evolution, 34: 934–943.CrossRefGoogle Scholar
  94. Schoen, D.J. 1983. Relative fitnesses of selfed and outcrossed progeny in Gilia achilleifolia (Polemoniaceae). Evolution, 37: 292–301.CrossRefGoogle Scholar
  95. Schoen, D.J. and M. Dubuc. 1990. The evolution of inflorescence size and number: A gamete packaging strategy in plants. Am. Nat., 135: 841–857.CrossRefGoogle Scholar
  96. Schoen, D.J. and D.G. Lloyd. 1992. Self- and cross-fertilization in plants. III. Methods for studying modes and functional aspects of self-fertilization. Int. J. Plant Sci., 153: 381–393.CrossRefGoogle Scholar
  97. Scribailo, R.W. and S.C.H. Barrett. 1994. Effects of prior self-pollination on outcrossed seed set in tristylous Pontederia sagittata (Pontederiaceae). Plant Sex. Reprod. 7: 273–281.Google Scholar
  98. Seavey, S.R. and K.S. Bawa. 1986. Late-acting self-incompatibility in angiosperms. Bot. Rev., 52: 195–219.CrossRefGoogle Scholar
  99. Shore, J.S. and S.C.H. Barrett. 1984. The effect of pollination intensity and incompatible pollen on seed set in Turnera ulmifolia (Turneraceae). Can. J. Bot., 62: 1298–1303.CrossRefGoogle Scholar
  100. Snow, A.A. 1982. Pollination intensity and potential seed set in Passiflora vitifolia. Oecologia, 55: 231–237.CrossRefGoogle Scholar
  101. Snow, A.A. 1986. Pollination dynamics of Epilobium canum (Onagraceae): Consequences for gametophytic selection. Am. J. Bot., 73: 139–151.CrossRefGoogle Scholar
  102. Snow, A.A. and P.O. Lewis. 1993. Reproductive traits and male fertility in plants: Empirical approaches. Ann. Rev. Ecol. Syst., 24: 331–351.Google Scholar
  103. Snow, A.A. and T.P. Spira. 1993. Individual variation in the vigor of self pollen and selfed progeny in Hibiscus moscheutos (Malvaceae). Am. J. Bot., 80: 160–164.CrossRefGoogle Scholar
  104. Spira, T.P. 1989. Reproductive biology of Hibiscus moscheutos (Malvaceae). In The Evolutionary Ecology of Plants (J.H. Bock and Y.B. Linhart, eds.), Westview Press, Boulder, CO, pp. 247–255.Google Scholar
  105. Spira, T.P., A.A. Snow, D.F. Whigham, and J. Leak. 1992. Flower visitation, pollen deposition, and pollen-tube competition in Hibiscus moscheutos (Malvaceae). Am. J. Bot., 79: 428–433.CrossRefGoogle Scholar
  106. Stephenson, A.G. 1982. When does outcrossing occur in a mass-flowering plant? Evolution, 36: 762–767.CrossRefGoogle Scholar
  107. Stout, A.B. 1928. Dichogamy in flowering plants. Bull. Torrey Bot. Club, 55: 141–153.CrossRefGoogle Scholar
  108. Sun, M. and F.R. Ganders. 1988. Mixed mating systems in Hawaiian Biden (Asteraceae). Evolution, 42: 516–527.CrossRefGoogle Scholar
  109. Thomson, J.D. 1986. Pollen transport and deposition by bumble bees in Erythronium: Influences of floral nectar and bee grooming. J. Ecol., 74: 329–341.CrossRefGoogle Scholar
  110. Thomson, J.D. and S.C.H. Barrett. 1981. Temporal variation of gender in Aralia hispida Vent. (Araliaceae). Evolution, 35: 1094–1107.CrossRefGoogle Scholar
  111. Thomson, J.D. and J. Brunet. 1990. Hypotheses for the evolution of dioecy in seed plants. Trends Ecol. Evol., 5: 11–16.PubMedCrossRefGoogle Scholar
  112. Thomson, J.D., M.V. Price, N.M. Waser, and D.A. Stratton. 1986. Comparative studies of pollen and fluorescent dye transport by bumble bees visiting Erythronium grandiflorum. Oecologia, 69: 561–566.CrossRefGoogle Scholar
  113. van Treuren, R. Bulsma, N.J. Ouborg, and W. van Delden. 1993. The effects of plant density and population size on outcrossing rates in locally endangered Salvia pratensis. Evolution, 47: 1094–1104.CrossRefGoogle Scholar
  114. Waddington, K.D. and B. Heinrich. 1979. The foraging movements of bumble bees on vertical “inflorescences”: An experimental analysis. J. Comp. Physiol., 134: 113–117.CrossRefGoogle Scholar
  115. Waller, D.M. and S.E. Knight. 1989. Genetic consequences of outcrossing in the cleistogamous annual, Impatiens capensis. II. Outcrossing rates and genotypic correlations. Evolution, 43: 860–869.CrossRefGoogle Scholar
  116. Waser, N.M. 1982. A comparison of distances flown by different visitors to flowers of the same species. Oecologia, 55: 251–257.CrossRefGoogle Scholar
  117. Waser, N.M. 1988. Comparative pollen and dye transfer by pollinators of Delphinium nelsonii. Func. Ecol., 2: 41–48.CrossRefGoogle Scholar
  118. Waser, N.M. and M.L. Fugate. 1986. Pollen precedence and stigma closure: A mechanism of competition for pollination between Delphinium nelsonii and Ipomopsis aggregata (Polemoniaceae). Oecologia, 70: 573–577.CrossRefGoogle Scholar
  119. Waser, N.M. and M.V. Price. 1982. A comparison of pollen and fluorescent dye carryover by natural pollinators of Ipomopsis aggregata (Polemoniaceae). Ecology, 63: 1168–1172.CrossRefGoogle Scholar
  120. Waser, N.M. and M.V. Price. 1984. Experimental studies of pollen carryover: Effects of floral variability in Ipomopsis aggregata. Oecologia, 62: 262–268.CrossRefGoogle Scholar
  121. Waser, N.M. and M.V. Price. 1991. Reproductive costs of self-pollination in Ipomopsis aggregata (Polemoniaceae): Are ovules usurped? Am. J. Bot., 78: 1036–1043.CrossRefGoogle Scholar
  122. Webb, C.J. and D.G. Lloyd. 1986. The avoidance of interference between the presentation of pollen and stigmas in angiosperms II. Herkogamy. New Zeal. J. Bot., 24: 163–178.Google Scholar
  123. Willson, M.F. 1983. Plant Reproductive Ecology. John Wiley & Sons, New York.Google Scholar
  124. Wolfe, L. and S.C.H. Barrett. 1989. Patterns of pollen removal and deposition in tristylous Pontederia cordata L. (Pontederiaceae). Biol. J. Linn. Soc., 36: 317–329.CrossRefGoogle Scholar
  125. Wyatt, R. 1983. Plant-pollinator interactions and the evolution of breeding systems. In Pollination Biology (L. Real, ed.), Academic Press, New York, pp. 51–96.Google Scholar

Copyright information

© Chapman & Hall 1996

Authors and Affiliations

  • Allison A. Snow
    • 1
  • Timothy P. Spira
    • 2
  • Rachel Simpson
    • 3
  • Robert A. Klips
    • 1
  1. 1.Department of Plant BiologyOhio State UniversityColumbusUSA
  2. 2.Department of Biological SciencesClemson UniversityClemsonUSA
  3. 3.Department of BiologyUniversity of MichiganAnn ArborUSA

Personalised recommendations