megasporen.
/ˈmɛɡəspɔː/, U.S. /ˈmɛɡəˌspɔr/ Botany.
The larger of the two kinds of spores produced by heterosporous cryptogams, which develops into the female gametophyte. Also: the analogous structure in seed plants (i.e. the immature embryo sac). Contrasted with microspore.
ΘΚΠ
the world > plants > part of plant > reproductive part(s) > seed > [noun] > parts of > embryo-sac
embryo sac1837
macrospore1855
megaspore1857
the world > plants > part of plant > reproductive part(s) > spore or sporule > [noun] > type of > megaspore or megasporange
macrospore1855
megaspore1857
gynospore1900
1857 A. Henfrey Elem. Course Bot. 598 It has been long known that the Lycopodiaceae and the Marsilaceae produce spores of different kinds, unlike especially in size, so that they are conveniently distinguished as microspores and megaspores.
1889 A. W. Bennett & G. R. M. Murray Handbk. Cryptogamic Bot. 11 Two different kinds of spore,..megaspores and..microspores.
1927 F. H. Knowlton Plants of Past vii. 89 In some species [of Lepidodendron]..there were two kinds, large ones called megaspores, in the lower part of the cone, and smaller ones (microspores) in the upper part.
1965 K. Esau Plant Anat. (ed. 2) xviii. 563 The ovule developing from the placenta of the ovary is the seat of formation of the megaspores (or macrospores).
1991 R. Goldring Fossils in Field iv. 65 Compressed megaspores may be readily seen in late Palaeozoic durainous coals.
This entry has been updated (OED Third Edition, June 2001; most recently modified version published online March 2022).
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n.1857