anatropous


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Related to anatropous: anatropous ovule

anatropous

(of flowering plants) having the OVULE inverted so that the MICROPYLE points towards the PLACENTA.
References in periodicals archive ?
With the J/M tree, where Ceratophyllum is sister to eudicots, well removed from Chloranthaceae, the most parsimonious position for Couperites is linked with Chloranthaceae, supported by its thick nexine, but attached below the crown group, because of its anatropous ovule.
alata are anatropous, subglobose, bitegmic, and crassinucellate, with a narrow conical nucellus (see Figure 4D, E).
Seed shape is described here as it is commonly illustrated with the hilum and micropyle at the 'bottom' of the seed, although it is acknowledged that this is developmentally the apex of the anatropous ovule.
The fossil and living taxa share the following characters: persistent floral tube, valvate sepals (unknown in Minsterocarpum), superior ovary, axile placentation, capsular fruit, loculicidal dehiscence (unknown in fossil Decodon), septum attached to outer wall of the valve at dehiscence, multiple anatropous seeds per locule, and a t obtrigonal shaped seed body with a sclerotic inner lining of the seed coat.
The ovary is monocarpellate and the mature ovule is anatropous, bitegmic and crassinucellate.
Gymnosperm ovules are always unitegmic and also orthotropous so that the podocarp ovule may be seen as anticipating the anatropous ovule of flowering plants, the second integument being responsible for the necessary asymmetric growth.
The ovule is of anatropous type and unitegmic (Fig.