from The American Heritage® Dictionary of the English Language, 5th Edition.

  • adjective Growing straight, so that the micropyle is at the end opposite the stalk. Used of an ovule.

from The Century Dictionary.

  • In botany, growing vertically or straight: applied specifically to an ovule in which the chalaza is at the evident base, and the orifice at the opposite extremity, the whole ovule being straight and symmetrical.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • adjective botany, of an ovule Growing straight and having the micropyle at the apex

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adjective (of a plant ovule) completely straight with the micropyle at the apex


from Wiktionary, Creative Commons Attribution/Share-Alike License

ortho- +‎ tropous


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  • The ancestral state in other characters is equivocal: e.g., bisexual vs. unisexual flowers, whorled vs. spiral floral phyllotaxis, presence vs. absence of tepal differentiation, anatropous vs. orthotropous ovules.

    A Disclaimer for Behe? 2009


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