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COMPARATIVE ONTOGENY OF THE INFLORESCENCE AND FLOWER OF HAMAMELIS VIRGINIANA AND LOROPETALUM CHINENSE (HAMAMELIDACEAE)

 

作者: Thomas Mione,   A. Linn Bogle,  

 

期刊: American Journal of Botany  (WILEY Available online 1990)
卷期: Volume 77, issue 1  

页码: 77-91

 

ISSN:0002-9122

 

年代: 1990

 

DOI:10.1002/j.1537-2197.1990.tb13530.x

 

出版商: Wiley

 

数据来源: WILEY

 

摘要:

A comparative developmental study of the inflorescence and flower ofHamamelisL. (4‐merous) andLoropetalum(R. Br.) Oliv. (4–5 merous) was conducted to determine how development differs in these genera and between these genera and others of the family. Emphasis was placed on determining the types of floral appendages from which the similarly positioned nectaries ofHamamelisand sterile phyllomes ofLoropetalumhave evolved. InHamamelis virginianaL. andH. mollisOliv. initiation of whorls of floral appendages occurred centripetally. Nectary primordia arose adaxial to the petals soon after the initiation of stamen primordia and before initiation of carpel primordia. InLoropetalum chinense(R. Br.) Oliv. floral appendages did not arise centripetally. Petals and stamens first arose on the adaxial portion, and then on the abaxial portion of the floral apex. The sterile floral appendages (sterile phyllomes of uncertain homology) were initiated adaxial to the petals after all other whorls of floral appendages had become well developed. In all three species, two crescent shaped carpel primordia arose opposite each other and became closely appressed at their margins. Postgenital fusion followed and a falsely bilocular, bicarpellate ovary was formed. Ovule position and development are described. The nectaries ofHamamelisand sterile phyllomes ofLoropetalumrarely develop as staminodia, suggesting a staminodial origin. However, these whorls arise at markedly different times and are therefore probably not derived from the same whorl of organs in a common progenitor. This hypothesis seems probable when one considers that the seemingly least specialized genus of the tribe,Maingaya, bears whorls of both staminodia and sterile phyllomes inside its whorl of stamens.

 

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