Darwin's Orchids: Then & Now
384
Darwin's Orchids: Then & Now
384Overview
Mirroring the structure of Fertilisation of Orchids, Darwin’s Orchids investigates flowers from Darwin’s home in England, through the southern hemisphere, and on to North America and China as it seeks to address a set of questions first put forward by Darwin himself: What pollinates this particular type of orchid? How does its pollination mechanism work? Will an orchid self-pollinate or is an insect or other animal vector required? And how has this orchid’s lineage changed over time? Diverse in their colors, forms, aromas, and pollination schemes, orchids have long been considered ideal models for the study of plant evolution and conservation. Looking to the past, present, and future of botany, Darwin’s Orchids will be a vital addition to this tradition.
Product Details
| ISBN-13: | 9780226173641 |
|---|---|
| Publisher: | University of Chicago Press |
| Publication date: | 12/22/2022 |
| Sold by: | Barnes & Noble |
| Format: | eBook |
| Pages: | 384 |
| Sales rank: | 906,818 |
| File size: | 27 MB |
| Note: | This product may take a few minutes to download. |
About the Author
Read an Excerpt
Darwin's Orchids
Then and Now
By Retha Edens-Meier, Peter Bernhardt
The University of Chicago Press
Copyright © 2014 The University of ChicagoAll rights reserved.
ISBN: 978-0-226-17364-1
CHAPTER 1
Darwin's Orchids (1862, 1877): Origins, Development, and Impact
Peter Bernhardt and Retha Edens-Meier
INTRODUCTION: WHY DID DARWIN STUDY ORCHIDS?
In 2009, scientists, naturalists, and journalists worldwide celebrated the bicentennial of the birth of Charles Darwin (1809–1882) and the 150th anniversary of the first edition of a book now known simply as The Origin of Species (Darwin 1859). If botanists, horticulturists, and plant conservationists wish to continue this happy tradition, we should recognize that first editions of Darwin's "plant books" appeared between 1862 and 1880, which means that the final 150th anniversary will be in 2030 (see Darwin 1880). The first book Darwin published following On the Origin of Species interpreted the morphology and biomechanics of flowers in the orchid family (Orchidaceae; Darwin 1862). Why did he select these flowers as model systems to expand on such concepts as "descent through modification" and adaptation, first addressed in On the Origin of Species?
We will probably never know for certain. Did Darwin's early love of flowers (Siegel 2011) in general predetermine a long-term, and unusually personal, inquiry on orchids decades later? Allen (1977; p. 45) noted that Darwin left a notebook from his university days that shows dissection of the anther and pollinia of Anacamptis morio (syn. Orchis morio). Yet it's most unlikely that Darwin's botany professor at Cambridge University, the Reverend John Stevens Henslow (1796–1861), turned his student into an enthusiastic orchidophile; the surviving Henslow-Darwin correspondence fails to mention orchids. It is far more likely that Henslow influenced Darwin's interests in the leaves of carnivorous plants and flower forms in Primula spp. (see Barlow 1967). Moreover, the orchid species Darwin encountered and collected during his 5 years on the HMS Beagle never evoked comments in his recounting of the voyage (Darwin 1845). In fact, orchid is not even an entry in the book's index.
Darwin's collections of orchids during that voyage were few, although Hooker (1860) credited him with the collection of the terrestrial and temperate Chloraea magellanica, a species that produces shiny white flowers that appear to be etched with bold green veins. Darwin was clearly unable to recognize the unique floral features of the Orchidaceae during this voyage, as 1 of the 2 "orchids" he collected in Tierra del Fuego and preserved in wine turned out to be a Calceolaria sp. (letter to Hooker; 19 May 1846). The story that the great botanist Robert Brown (1773–1858) stimulated Darwin's interest in orchid pollination by convincing him to read Sprengel (1793) did not convince Ghiselin (see foreword in Darwin 1984; pp. xvii–xviii), who insisted that Darwin was experimenting on a range of flowers as early as 1839.
In fact, Darwin's notes and correspondence with J. D. Hooker (1817–1911), the influential botanist and Director of the Royal Botanic Gardens at Kew, show they began discussing irritability in orchid flowers as early as 8 December 1844. In a letter to W. D. Fox (1805–1880) dated 8 February 1857, Darwin asked his cousin if he would observe any Mormodes spp. in bloom in a private collection at Oulton House, to see "which eject their pollen masses when irritated" (see Chapter 9). There is no surviving record of a reply from Fox.
Of course, the mere presence of existing correspondence can't prove Darwin's intense interest in any topic. For example, while his published and/or online letters from 1858 to 1859 fail to mention orchid flowers, it's obvious he recorded natural rates of insectmediated removal of pollinia from flowers in populations of Ophrys muscifera (syn. O. insectifera) in 1858 (Darwin 1862). Therefore, the most plausible explanation for Darwin's orchidophilia remains with his seventh son, Francis (1848–1929): "He [C. Darwin] was probably attracted to the study of Orchids by the fact that several kinds are common near Down" (Darwin F 1896; p. 303). More recently, Boulter (2008; p. 157) reported that he read a notebook that C. Darwin had written in during his early days at Down House in the 1840s. Boulter insisted that Charles and his wife Emma transplanted orchids from the wild into their hothouse to better observe them.
THE VICTORIANS AND THEIR BELOVED ORCHIDS (DARWIN AS ORCHID COLLECTOR)
Whatever the case, Darwin's scientific interest in orchids parallels Victorian sentimentality toward flowers in general, rising literacy with respect to education in botany (see Scourse 1983), and the 19th-century fad for privately owned, living collections of exotic plants (Tyler-Whittle 1970). In England in particular, greenhouse technology improved significantly during the 19th century as iron became cheaper and the tax on windowpanes was repealed (Tyler-Whittle 1970; Woods and Warren 1988). A mania for tropical, epiphytic-lithophytic orchid species was just one of many plant-collecting passions of the Victorian era that also included tropical/temperate species of ferns, aquatic plants, Rhododendron spp., and palms, among others (Scourse 1983). However, the craze for wild-harvested, epiphytic orchids proved to be a longer-lasting and resilient mania (Bernhardt 1989b; Darwin 1868; Siegel 2011) for two overlapping reasons. First, most of England's expanding middle class did not own enough land to support the culture of choice groves of giant conifers and Magnolia grandiflora from North America or the arborescent Rhododendron spp. of the Himalayas. They could not afford to build either the huge tropical pool houses required to sustain the South American Victoria amazonica (Coats 1970), or the palm conservatories associated with Kew Gardens and the great private estates. Instead, small conservatories and glasshouses attached to urban and suburban homes (Woods and Warren 1988) housed dozens of orchid specimens from Old and New World tropics. Some popular writings of the day offered stories about how orchids were collected, bringing mild excitement to armchair travelers. A number of these authors insisted that orchid collections conferred status on their owners, as their cultivation showed good taste and horticultural expertise (see Boyle 1893). Second, Victorian collectors found orchids unique, as mass propagation of these plants from either seeds or meristem tissues was impossible until the 20th century (Bernhardt 1989b).
DARWIN'S ORCHID STUDIES BEFORE 1862
By 1861, Darwin had amassed a sizable collection of orchids from collections at Kew and the commercial nurseries of James Veitch and sons as well as from gifts given by private collectors (Siegel 2011). Addressing his father's research on orchid flowers, Francis Darwin (1896; p. 303) wrote that "in 1861 he [C. Darwin] gave part of summer and all of autumn to the subject." Some people have misread this sentence and come to the conclusion that all Darwin's orchid research for the first edition of On the Various Contrivances began and ended in 1861. While it is reasonable to assume that it took Darwin 10 months to write the book, and that most of his dissections of exotic species were performed and recorded in this space of time, his correspondence indicates that his work on British species was older. In particular, there is Darwin's famous letter to the Gardener's Chronicle (4–5 June 1860) discussing his observations, before and during 1858, recording (insect-mediated) pollinia removal in flowers of Ophrys muscifera. Within the same letter, he contrasts these results with the absence of pollinia removal and self-pollination in Ophrys apifera (see Chapter 3). It was not until the second edition of the orchid book that Darwin (1877) finally released his data on poor pollinia removal rates in flowers of Orchis morio during the cold and wet season of 1860 (see Chapter 2).
Based on collected correspondence, it was in 1860 that Darwin first attempted to enlist other naturalists to make observations on orchid flowers native to Britain. He wrote Alexander Goodman More (1830–1895) on 24 June 1860, but More would not respond until the following year. So the belief that Darwin began and completed his entire study on orchid floral biology pollination in 1861 is a nice story, but it tends to fall apart after reading the first half of one sentence in Darwin (1862; pp. 34–35): "I have been in the habit for twenty years of watching Orchids."
BUT WAS DARWIN A POLLINATION BIOLOGIST BEFORE 1862?
But this sentence is a double-edged sword. If we complete it, we have to wonder if Darwin was much of a pollination biologist by modern standards: "[I] have never seen an insect visit a flower, excepting butterflies twice sucking O. pyramidalis and Gymnadenia conopsea" (Darwin 1862; pp. 34–35). Therefore, in the first edition of his book, Darwin's firsthand descriptions of orchid flower-insect interactions are few and usually credited to other people. In the second edition, Darwin (1877) generously credits the observation of the pollination of Herminium monorchis by a parasitic wasp and moth pollination of Gymnadenia conopsea to his son George (1845–1912). Müller (1871) also complained that visitors to the flowers of Orchis were infrequent, but it was Müller, not Darwin, who observed and collected bees visiting several Orchist spp. (Müller 1883; see Chapter 2). It is ironic to think that Charles Darwin, a great collector of beetles in his youth and a hunter of so many different, and far larger, animals in South America (Darwin 1845), was inept with a butterfly net. Twenty years of bad luck, season after season, seems unlikely even if we emphasize a combination of personal ill health and bad weather in Kent from 1844 to 1861. Grant Hazlehurst, assistant warden of Downe Bank for the Kent Wildlife Trust, noted that members of the trust continue to revisit Darwin's favorite orchid sites each spring. They spend some time catching and photographing male wasps pollinating Ophrys insectifera on sunny, cloudless days (Grant Hazlehurst, personal communication).
We suspect that much of Darwin's lack of field observation was based on two personal limitations. First, his correspondence shows him to be an extremely busy man who was always juggling several lines of research at the same time. It is unlikely he could spend hours in the field every day covering the full flowering seasons of each orchid species as fieldworkers do, or should do, today. We presume that then as now, each population of orchids remained in bloom for 2 or 3 weeks. Second, Darwin never accepted K. C. Sprengel's (1730–1816) interpretation of the false nectar flower (the scheinsaftblumen; sensu Sprengel 1793). That is, Sprengel noted that even though the flowers of some species always fail to secrete nectar, they do produce appropriate visual and/or scent advertisements and repeatedly attract insect pollinators. These insects probe for a nonexistent reward and serve as passive pollen taxis. While Darwin read Sprengel's treatise on pollination, he confided in a letter to Harvard's professor of botany, Asa Gray (1810–1888), that it was "a curious old book full of truth with some little nonsense" (19 January 1863).
DARWIN ON NECTAR SECRETION IN ORCHIDS
Ironically and consequently, the nectar glands Darwin describes in some of his orchid flowers in both the first and the second edition of his book have since been reinterpreted as floral sculptures that fail to secrete nectar but have other functions during the act of insect-mediated pollination. Darwin's predilection for interpreting small, novel floral structures as functional nectar glands was accepted with enthusiasm by Müller (1871) and others. However, few botanists today regard the hammer glands on or in the flowers of most lady's slipper orchids (Cypripedium) as nectar glands (see Chapter 10), breaking with Darwin (1862, 1877) and Müller (1871). We think it's notable that following the publication of his first edition, Darwin netted insects visiting the flowers of Spiranthes autumnalis and Epipactis latifolia (Darwin 1877), both nectar-secreting species. Had he understood that entire lineages in the orchid family fail to produce any reward (Tremblay et al. 2005; Bernhardt and Edens-Meier 2010; see Chapters 2, 3, 4, 5, 7, 10) and remain pollinator limited (sensu Committee on the Status of Pollinators in North America 2007), he might have spent more time in the field or even reinvested his time in another diverse angiosperm lineage with bilaterally symmetrical flowers.
Would the book have had the same general appeal and long-term impact if, for example, he compared flower and pollinator interactions in the pea family (Fabaceae)? We think not, considering the specific plant collection fads during the Victorian age. Ignorance was bliss in Darwin's case. At least he never experienced the disappointment of spending 3 seasons at the same population of Cypripedium reginae, only to capture 6 insects carrying the pollen of the large, colorful but nectarless flowers (Edens-Meier et al. 2011).
DARWIN'S ORGANIZATION OF THE FIRST EDITION (1862): ORCHIS AS A CELEBRITY
Therefore, the first edition of Darwin's book would seem to be an unlikely place for a breakthrough in evolutionary botany. It is a rather short study in the comparative floral morphology and biomechanics of, at the time, 28 species (in 15 genera) distributed throughout Britain. The flowers of an additional 43 genera represent 42 species with Neotropical and Paleotropical distributions. The outline of the book follows the classification of the orchid family by John Lindley (1799–1865), then editor of the Gardner's Chronicle. Most historians of orchidology treat Lindley's classification as the first real attempt to subdivide all species into tribes (see Dressler 1981) based primarily on variation in the architecture and fusion of the floral column and the alignment of the anther(s) to the stigma (Lindley 1826).
To make the book's topic more familiar and appealing to a British audience, Darwin employed an introductory technique he used in On the Origin of Species. He would repeat this technique in all his plant books. He began the book with a simple and familiar example. For instance, Darwin (1859) introduces the new and complicated concept of natural selection by beginning the book with a survey of popular breeds of domesticated pigeons produced by artificial selection. It was, after all, an era in which people ate, bred, raced, exhibited, and shot pigeons according to breed.
(Continues...)
Excerpted from Darwin's Orchids by Retha Edens-Meier, Peter Bernhardt. Copyright © 2014 The University of Chicago. Excerpted by permission of The University of Chicago Press.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.
Table of Contents
PrefacePeter Bernhardt and Retha Edens-Meier
I. Darwin Shares His Orchids
1 Darwin’s Orchids (1862, 1877): Origins, Development, and Impact
Peter Bernhardt and Retha Edens-Meier
II. Darwin’s Orchids of the English and Eurasian Countrysides
2 Darwin on the Pollination of Orchis: What He Taught Us and What We Can Tell Him Today
Giovanni Scopece, Salvatore Cozzolino, and Amots Dafni
3 Ophrys Pollination: From Darwin to the Present Day
Nicolas J. Vereecken and Ana Francisco
III. Darwin and His Colleagues: Orchid Evolution in the Southern Hemisphere
4 Pollination of South African Orchids in the Context of Ecological Guilds and Evolutionary Syndromes
Steven D. Johnson
5 Phylogeny of Orchidaceae Tribe Diurideae and Its Implications for the Evolution of Pollination Systems
Peter H. Weston, Andrew J. Perkins, James O. Indsto, and Mark A. Clements
Appendix 5.1: Morphological Character States Used to Construct a Phylogeny of the Diurideae
6 Pollination of Spider Orchids (Caladenia syn. Arachnorchis) by Wasps . . . and Others: A Lingering Post-Darwinian Mystery
Sophie Petit
7 The Sun Orchids (Thelymitra) Then and Now: Large Flowers versus Small Flowers and Their Evolutionary Implications
Retha Edens-Meier and Peter Bernhardt
IV. Darwin and His Colleagues: Orchid Evolution in the Tropics
8 Pollination Biology and Evolutionary History of Angraecoid Orchids: From Darwin to the Present Day
Claire Micheneau, Jacques Fournel, and Thierry Pailler
9 Orchids and Neotropical Pollinators since Darwin’s Time
David W. Roubik
V. Extravagant Architecture: The Diandrous Orchids
10 Pollination and Floral Evolution of Slipper Orchids (Subfamily Cypripedioideae)
Retha Edens-Meier, Yi-bo Luo, Robert Pemberton, and Peter Bernhardt
VI. Overview: The Influence of Color Perception and Climate Change
11 Color and Sexual Deception in Orchids: Progress toward Understanding the Functions and Pollinator Perception of Floral Color
A. C. Gaskett
12 Impacts of Extreme Weather Spells on Flowering Phenology of Wild Orchids in Guangxi, Southwestern China
Hong Liu, Chang-Lin Feng, Xiao-Qing Xie, Wuying Lin, Zheng-Hai Deng, Xin-Lian Wei, Shi-Yong Liu, and Yi-Bo Luo
Summary
Retha Edens-Meier and Peter Bernhardt
References
List of Contributors
Species Index
General Index