
デボン紀後期の三翼種子化石 Alasemenia tria は、包被のない初期種子植物の分散戦略を示唆している。


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The ovules or seeds (fertilized ovules) with wings are widespread and especially important for wind dispersal. However, the earliest ovules in the Famennian of the Late Devonian are rarely known about the dispersal syndrome and usually surrounded by a cupule. From Xinhang, Anhui, China, we report a new taxon of Famennian ovules, Alasemenia tria gen. et sp. nov. Each ovule possesses three integumentary wings evidently extending outwards, folding inwards along abaxial side and enclosing most part of nucellus. The ovule is borne terminally on smooth dichotomous branches and lacks a cupule. Alasemenia suggests that the integuments of the earliest ovules without a cupule evolved functions in wind dispersal and probable photosynthetic nutrition. It indicates that the seed wing originated earlier than other wind dispersal mechanisms such as seed plume and pappus, and that three- or four-winged seeds were followed by seeds with less wings. Mathematical analysis shows that three-winged seeds are more adapted to wind dispersal than seeds with one, two or four wings under the same condition.

### Competing Interest Statement

The authors have declared no competing interest.

Alasemenia, the earliest ovule with three wings and without cupule

最古の三翼の種子化石-alasemenia-tria-包被なしの初期種子植物の分散戦略


最古の三翼の種子化石 Alasemenia tria - 包被なしの初期種子植物の分散戦略
