Am. J. Bot. Li-Cor Advertisement
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

First published online January 7, 2010; doi:10.3732/ajb.0900239
American Journal of Botany 97: 311-323 (2010)
© 2010 Botanical Society of America, Inc.
 		  Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter
What's this?
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
ajb.0900239v1
97/2/311    most recent
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Steiner, K. E.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Steiner, K. E.
Agricola
Right arrow Articles by Steiner, K. E.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

Reproductive Biology

Twin oil sacs facilitate the evolution of a novel type of pollination unit (meranthium) in a South African orchid1

Kim E. Steiner

Botany Department, California Academy of Sciences, 55 Music Concourse Drive, San Francisco, California 94118 USA

ABSTRACT

The unique floral morphology of the South African orchid H. pulchra, with its twin meranthia, is best explained as an adaptation to pollination by oil-collecting bees. Flowers consisting of meranthia (floral parts that function as single pollination units; commonly observed in garden Iris) are extremely rare among the angiosperms and their significance poorly understood. Unlike all other known examples of meranthia, the novel type described for H. pulchra is not bilabiate. All Huttonaea species are unique in having twin petal sacs with glandular verrucae that secrete oil and are pollinated by Rediviva (Melittidae) oil-collecting bees. But only Huttonaea pulchra has long and widely divergent petal claws that place the oil sacs well beyond the reach of a centrally positioned bee. The wide separation of these sacs forces the pollinator, R. colorata, to visit each side of the flower independently and effectively divides the flower into two meranthia. Molecular data indicate that the evolution of the Huttonaea-type meranthium was dependent on the prior evolution of the oil flower/oil bee relationship. Meranthium evolution was also facilitated by the presence of oil in two separate structures (petal sacs) that were not physically constrained to remain in close proximity.

Key Words: Diseae • floral evolution • Huttonaea • meranthium • oil-collecting bees • Orchidaceae • pollination • Rediviva

Received for publication 12 August 2009. Accepted for publication 9 November 2009.

FOOTNOTES

1 The author thanks P. Fritsch and S. Dötterl for valuable comments on earlier versions of the manuscript, S. Dötterl with assistance on the statistical analyses, and B. Cruz with the DNA sequencing. This work was partially supported by the L. and E. Rose Memorial Fund. The KwaZulu-Natal Wildlife Permits Office is gratefully acknowledged for permission to collect in KwaZulu-Natal.

2 E-mail: ksteiner{at}calacademy.org


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?




HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2010 by the Botanical Society of America, Inc.