Journal of Experimental Botany Advance Access published February 27, 2008
Journal of Experimental Botany, Page 1 of 3
Journal of Experimental Botany, Vol. 64, No. 18, pp. 5791–5793, 2013
doi:10.1093/jxb/ern038
doi:10.1093/jxb/ern038 Advance Access publication 28 February, 2008
FLOWERING NEWSLETTER
My favourite flowering image
Peter K. Endress*
Institute of Systematic Botany, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland
Received 4 January 2008; Accepted 8 January 2008
Abstract
Key words: Drawings, Eupomatia, flowering, illustrations.
Nick Battey asked me to write about my favourite
flowering image. The word ‘flowering’ implies a process,
the time in the life of a flower when pollen is available
and the stigma is receptive. The process of flowering has
been studied in relatively few plants. I do not think that
the process from opening to fading of a flower in
Arabidopsis or Antirrhinum has been analysed in detail
by developmental morphologists, developmental geneticists, or ecologists. Many changes can happen during
anthesis of a flower, changes in colour and scent, and
growth and movement of floral organs. These changes
also contribute to the fascination of some ornamental
flowers. They emphasize the ephemeral nature of flowers.
One cannot keep a flower, one has to enjoy it in its best
moment. A rose flower continuously changes its features
during anthesis. The peak of its beauty for a rose lover
may be a short episode in this development.
Which is my favourite flowering image? This is a tricky
question. Should it be an image that conveys an unusual
amount of information? Should it be an image that is
aesthetically pleasing in a special way? Should it be a an
image that puzzled me and that I cannot forget so easily?
I made a list of several possibilities for these different
aspects and pondered them. Finally, I chose the third
aspect and decided on an image that I drew myself and
that puzzled me immensely when I drew it and was an
eye-opener for me.
In the 1970s, I focused on a number of small, isolated,
poorly known basal angiosperm families. One of them was
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The heuristic value of drawings in research is emphasized, based on a drawing of flowers of Eupomatia
bennettii.
Eupomatiaceae (Rix and Endress, 2007). I was somewhat
familiar with the floral structure as I had studied fixed floral
material and published the observations (Endress, 1977).
When I was in the field in Australia and New Guinea in
1977 I was focusing on other families and therefore missed
the flowering time of Eupomatiaceae. However, thanks to
experienced gardeners, we could later cultivate Eupomatiaceae in the Botanic Garden of the University of Zurich.
The first plant that came to flower was a specimen of
Eupomatia bennettii. A young plant produces only a single
flower in the first year it comes to bloom. Its flower bud
opened in the morning of 5 February 1979. This was quite
an event. I not only photographed the flower but, when it
had opened and looked similar to the illustration in Curtis’s
Botanical Magazine (Hooker, 1855) (under the wrong
name Eupomatia laurina), which was the best available
illustration of a flower at that time, I also began to draw it
with pencil and pastel because this is the best way to
familiarize oneself with a plant and to make critical
observations (Fig. 1A). The anthesis process had never
been studied before and was thus completely unknown.
And now the surprise: a shocking experience! At first,
I thought my capacity to recognize things three-dimensionally was hampered. When I checked organs just drawn
a few minutes earlier they looked different, and this was the
same with all the organs, although the aspect of the whole
flower had not noticeably changed. It did not help to
correct the drawing because the same frustration continued
after the corrections. So I realized that all the organs were
constantly moving. The flower was still in the opening
process. I also realized that the reason why the overall
image of the flower didn’t appear to change was because
the organs were spirally arranged and thus all organs had
the same divergence angles and the movement of the
individual organs was highly co-ordinated. My first
drawing (Fig. 1A) shows the flower at about 09.00 h.
When I was certain that the flower was fully open, at about
14.00 h, I made a second drawing (Fig. 1B).
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Later, I made more detailed studies on the entire
flowering process in the two species of Eupomatia known
at that time (Endress, 1984). The flowers have an unusual
architecture: they look as if they are inside out. They are
perianthless but have a cap-like cover that is really a bract.
The bract falls off like a calyptra when the flower first
opens. The stamens are the outermost floral organs,
followed by numerous petaloid inner staminodes and
a gynoecium of numerous basally united, apically flattened carpels forming a platform with stigmatic knobs in
the floral centre. Each flower performs a fixed programme
of movements during anthesis. After the calyptra has
detached from the floral periphery, the petaloid inner
staminodes curve backward. When they are maximally
recurved after several hours, the flower is fully open and
is in the female phase. Later, the staminodes incurve
again, blocking access to the gynoecium. The anthers
open, and the flower comes into the male phase. The
sequence of events is the same in all three species [a third
one was described subsequently (Jessup, 2002)]. But the
length of anthesis is different: one day in Eupomatia
laurina and E. barbata and two or three days in E.
bennettii (Endress 1984, 2003). The flowers are pollinated
by tiny weevils, which also lay their eggs in the flowers.
After the male phase, stamens and staminodes, which are
united at the base, fall off as a unit and the larvae of the
weevils develop in the nutritious staminodial tissue on the
forest floor (Armstrong and Irvine, 1990).
The entire process of floral development up to anthesis
has also been studied. The nature of the calyptra as a bract
has been confirmed by comparative developmental morphology (Endress, 2003) and by molecular genetics (Kim
et al., 2005). A developmental study of incipient flowers
also showed how all the floral organs are positioned in
a regular spiral (Endress, 2003), a reason for my
puzzlement when I first drew the flower.
This essay on my drawing a flower that perplexed me
while I was drawing it also allowed me to ask myself how
I would characterize a good image in a scientific work. A
good image is aesthetically pleasing and rich in information. It should convey information in a pleasant and
simple way.
Last but not least, I would like to emphasize the great
heuristic value of drawings, an ‘art’ that today is less
valued than in earlier times. Of course, to do naturalistic
drawings takes time, but the process of hand drawing can
provide valuable insights into patterns or processes of
nature, which can scarcely be achieved by merely looking
at and analysing a picture taken by a camera or the SEM.
Since I was at school I have made hundreds of drawings
of plants. They taught me to see the three-dimensional
structure of flowers like a landscape. Words are not able
to convey an exact image of a complicated architecture.
Pictures can convey patterns in nature much better than
words (Rockwell and Lagarias, 2006; Ribisi et al., 2007).
Words can only highlight certain features that an author
views as important in a given context.
An interesting experiment was once made in a scientific
drawing class. A student had to draw a plant of Rhoeo
spathacea (Commelinaceae) based on a detailed descriptive text (Heller and Reble, 1990). He had not seen the
plant before. Only after he had finished his illustration did
he receive a live plant and drew it again. The two
drawings look very different, and, looking at the first
drawing it is difficult to recognize the plant (Heller and
Reble, 1990).
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Fig. 1. Flower of Eupomatia bennettii F. Muell. (Endress 4358, Mt. Nebo, Queensland), drawn on 5 February 1979. The drawings show the inner
staminodes bearing secretory warts, in (B) also the exposed gynoecium. (A) Flower drawn at about 09.00 h, still in the process of opening. (B) The
same flower drawn at about 14.00 h, fully open, in the female phase of anthesis.
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Acknowledgements
For successful cultivation of Eupomatia bennettii over many years,
I especially thank the gardeners Leonhard Braun and René Stalder.
I also thank Alex Bernhard for his help with the reproduction of the
figure.
References
Armstrong JE, Irvine AK. 1990. Functions of staminodia in the
beetle-pollinated flowers of Eupomatia laurina. Biotropica 22,
429–431.
Endress PK. 1977. Über Blütenbau und Verwandtschaft der
Eupomatiaceae und Himantandraceae (Magnoliales). Berichte der
Deutschen Botanischen Gesellschaft 90, 83–103.
Endress PK. 1984. The flowering process in the Eupomatiaceae
(Magnoliales). Botanische Jahrbücher für Systematik 104, 297–319.
Endress PK. 2003. Early floral development and the nature of the
calyptra in Eupomatiaceae. International Journal of Plant
Sciences 164, 489–503.
Heller M, Reble C. 1990. Wissenschaftliches Zeichnen: Museum
für Gestaltung Zürich. Museum für Gestaltung, Zürich
Hooker WJ. 1855. Eupomatia laurina. Curtis’s Botanical Magazine 81, t. 4848.
Jessup LW. 2002. A new species of Eupomatia R. Br.. (Eupomatiaceae) from Queensland. Austrobaileya 6, 333–335.
Kim S, Koh J, Ma H, Hu Y, Endress PK, Hauser BA, Buzgo M,
Soltis PS, Soltis DE. 2005. Sequence and expression studies of
A-, B-, and E-class MADS-box genes in Eupomatia (Eupomatiaceae): support for the bracteate origin of the calyptra. Botanical
Journal of the Linnean Society 148, 265–274.
Ribisi Jr S, Yu K, Lambertson L. 2007. A picture is worth
a thousand questions. The American Biology Teacher, Online
Publication. March 2007, 42–47.
Rix M, Endress PK. 2007. 591. Eupomatia laurina, Eupomatiaceae. Curtis’s Botanical Magazine 24, 162–167.
Rockwell NC, Lagarias JC. 2006. The structure of phytochrome:
a picture is worth a thousand spectra. The Plant Cell 18, 4–14.
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Thus the value and necessity of illustrations is clear.
They are primarily important to help the reader understand the content of a text. It is dismaying to see how
sloppy images, and plates of images, are sometimes in
publications. To compose good plates of images can be
thought of as an art. Not only should each single image
be good, but also the composition of a plate, which
should be designed with an overall comparative context
in mind. In this way plates of images should be valued
as independent, integral parts of a publication and
should not be seen just as assemblages of images
supporting the text. This is not appreciated by some
scientific journals, which require that the sequence of
images should strictly follow the sequence of their
citation in the text.
However, illustrations are not only important as a visual
demonstration of structures in publications but also as
instruments for the process of scientific discovery. ‘My
favourite flowering image’ is of this category.