heterogamy
(hɛtəˈrɒgəmɪ)
[f. as prec. + -y.]
The quality or condition of being heterogamous.
1. Bot. Mediate or indirect fertilization of plants.
| 1874 R. Brown Man. Bot. ix. 418 These circuitous methods of fertilisation may be called Heterogamy, or ‘crooked fertilisation,’ in contradistinction to the typical and orthodox method, which may be styled Orthogamy, or direct (‘straight’) fertilisation. |
2. Biol. The succession of differently organized generations of animals or plants, as where sexual generation alternates with parthenogenesis.
| 1884 A. Sedgwick tr. Claus' Zool. I. 543 Chermes affords an example of heterogamy in that two different oviparous generations follow one another: a slender and winged summer generation, and an apterous generation which is found in autumn and spring and lives through the winter. 1886 Rolleston & Jackson Anim. Life Introd. 31 Alternation of Generations..whether in the form known as metagenesis, i.e. the alternation of asexual and sexual individuals, or as heterogamy, i.e. the alternation of parthenogenetic and sexual races. Ibid. 508 [In Insects] Alternation of Generations is coupled with parthenogenesis, and is known in this case as Heterogamy. 1889 Geddes & Thomson Evol. Sex xv. 207 A sexless fern-plant forms special reproductive cells (spores), which develop parthenogenetically into a sexual prothallus, from the fertilised egg-cell of which the fernplant arises..[this] is called by zoologists, in reference to flukes for instance, heterogamy. |
3. Biol. a. The condition of having or producing heterogametes; reproduction involving heterogametes. b. Heterogamous reproduction.
| 1894 S. H. Vines Text-bk. Bot. iii. 275 Heterogamy:—a. Oogamy: sexual cells, oospheres and undifferentiated male cells... b. Carpogamy: no differentiated female cell. 1897 Ann. Bot. XI. 106 Isogamy, heterogamy, and conjugation have been observed. Ibid. 118 The curious heterogamy of Aphanochaete. 1925 E. B. Wilson Cell (ed. 3) vii. 584 A third type is true heterogamy... The gametes are here widely different from each other. 1966 McGraw-Hill Encycl. Sci. & Technol. III. 83/2 Heterogamy is also characteristic of land plants and is regarded as the most advanced type of sexual reproduction. |
Hence heteroˈgamic a., characterized by heterogamy (sense 3).
| 1904 Science 3 June 866/1 In the heterogamic subdivision of the homothallic group, a distinct and constant differentiation exists between the zygophoric hyphæ and the gametes derived from them. 1904 Proc. Amer. Acad. Arts & Sci. Aug. 210 Two genera of the homothallic group..are heterogamic in that their gametes show a certain constant inequality in size. 1927 Gwynne-Vaughan & Barnes Struct. & Devel. Fungi 112 None of the heterothallic forms among the mucors is known to be heterogamic. |