单词 | heterogamous |
释义 | heterogamousadj. 1. Botany. Variously applied to conditions in which stamens and pistils are not regularly present in each flower or floret. Applied: (a) originally by de Candolle to plants having flowers monœcious, diœcious, or polygamous; (b) by Lessing to composites whose capitula or flower-heads contain florets differing in sex; (c) by Trinius to grasses in which the arrangement of the sexes is different in different spikelets. ΘΚΠ the world > plants > part of plant > reproductive part(s) > flower or part containing reproductive organs > [adjective] > having or relating to parts > of or having stamens or pistils > having neither stamens or nor pistils imperfect1704 neutral1755 neuter1785 heterogamous1839 1839 J. Lindley Introd. Bot. (ed. 3) i. ii. 157 If all the flowers are hermaphrodite in the capitulum, it is homogamous; if the outer are neuter, or female, and the inner hermaphrodite, or male, it is heterogamous. 1842 in W. T. Brande Dict. Sci., Lit., & Art 1866 J. Lindley & T. Moore Treasury Bot. Heterogamous, when in a capitulum the florets of the ray are either neuter or female, and those of the disk male. 1872 D. Oliver Lessons Elem. Bot. (new ed.) ii. 196 If all the florets of a flower-head (capitulum) be perfect, the flower-heads are homogamous (Dandelion); if part of them be imperfect, the heads are heterogamous (Daisy). 2. Biology. Characterized by the alternation of differently organized generations, as of a parthenogenetic and a sexual generation. ΚΠ 1897 T. C. Allbutt et al. Syst. Med. II. 1031 Certain species [of Nemathelminthes] possess what is known as the ‘free rhabditis form’ and are heterogamous. 3. Of or pertaining to irregular marriage. ΚΠ 1862 M. Hopkins Hawaii 159 Besides these he may have had other heterogamous connexions. 4. Biology. Involving, having the character of, or producing heterogametes. ΘΚΠ the world > life > biology > biological processes > procreation or reproduction > reproductive substances or cells > [adjective] > gametes gametic1883 gametal1888 oogamous1888 progamic1891 heterogamous1895 gametoid1903 heterogametic1910 homogametic1910 pregamic1934 planogametic1957 1895 J. R. Green Man. Bot. I. i. ii. 215 The smaller are held..to be male, and the larger female. Plants with such gametes are called heterogamous. 1900 Ann. Bot. 14 662 The union of heterogamous walled aplanogametes. 1925 E. B. Wilson Cell (ed. 3) vii. 593 In true heterogamous forms the macrogamete becomes a large, non-motile cell. 1957 H. C. Bold Morphol. Plants iii. 55 These plants are the male and female gametophytes which liberate the heterogamous gametes at maturity. 1969 G. W. Prescott Algae i. 42 Sexual reproduction may include isogamous, anisogamous, or heterogamous methods, with or without special sex organs. This entry has not yet been fully updated (first published 1898; most recently modified version published online September 2021). < adj.1839 |
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