Axial nature of the cupule-bearing organ in Caytoniales

Caytoniales are an important group of seed plants, and the nature of their female reproductive organ may influence interpretations of the seed plant phylogeny and the origin of angiosperms. Although not convincingly demonstrated by clear evidence, cupules on previously described specimens were inter...

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Bibliographic Details
Published in:Journal of Systematics and Evolution
Main Author: Wang, Xin
Format: Report
Language:English
Published: WILEY PERIODICALS, INC 2010
Subjects:
angiosperms
Caytoniales
cupule
evolution
Paracaytonia
seed plants
systematics
Yixian Formation
SEED-PLANT PHYLOGENY
EARLY EVOLUTION
ORIGIN
FERNS
CHINA
ARCHAEFRUCTUS
ANTARCTICA
FLOWER
Plant Sciences
Antarc*
Antarctica
Online Access:http://ir.nigpas.ac.cn/handle/332004/19747
https://doi.org/10.1111/j.1759-6831.2010.00072.x
Description
Summary:Caytoniales are an important group of seed plants, and the nature of their female reproductive organ may influence interpretations of the seed plant phylogeny and the origin of angiosperms. Although not convincingly demonstrated by clear evidence, cupules on previously described specimens were interpreted as being distichously arranged, implying that the cupule-bearing organ in Caytoniales was a pinnate megasporophyll. Here a female reproductive organ of Paracaytonia hongtaoi gen. et sp. nov. (Caytoniales) is reported from Liaoning, China. The well preserved specimen clearly shows a spiral arrangement of cupules along the reproductive axis, suggesting that the cupule-bearing organ in Caytoniales is not a megasporophyll but a branch. This new information on the axial nature of the cupule-bearing organ in Caytoniales has significant implications on the placement of Caytoniales in the seed plant phylogeny and interpretation of the relationship between Caytoniales and angiosperms.

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