446 i Flora Unveiled
The term was first used in biology in the seventeenth century to describe the seemingly
sudden transformation of insects from one form to another. For example, in 1669, the
Dutch biologist Jan Swammerdam used a microscope to study the stages of insect devel-
opment and demonstrated that these transformations were gradual and continuous.
Linnaeus applied the term to plant development in his Metamorphosis Plantarum (1755),
which outlined his medulla– cortex theory for the formation of pistils and stamens (see
Chapter 13).^52 Linnaeus’s Metamorphosis Plantarum is the likely inspiration for Goethe’s
German title, Versuch die Metamorphose der Pflanzen zu erklären (Attempt to Explain the
Metamorphosis of Plants).
In Metamorphosis of Plants (1790), Goethe compares plant development to the
ascension of a ladder that culminates in sexual reproduction. Plant metamorphosis,
he states,
may be observed at work step by step from the first seed leaves to the final develop-
ment of the fruit. By transmutation of one form into another, it ascends as though on
the rungs of an imaginary ladder to the climax of Nature, reproduction through two
sexes.^53At this early stage of his own transformation into a botanist, Goethe expressed no doubts
about the sexual theory as he now interpreted it, although, as we shall see, his interpretation
was unorthodox. Like Aristotle’s Scala Natura, Goethe’s developmental ladder is a hier-
archical system from the least perfect (vegetative) structures to the most perfect (sexual)
structures. In contrast to the Scala Natura, which places plants at the bottom, Goethe con-
siders plants on a par with animals, at least in the realm of sexuality. For esoteric reasons
that will be explained later, Goethe even considered hermaphroditic flowers to be superior
to animals as exemplars of sexual reproduction.
Goethe states at the outset that he will restrict his discussion of metamorphosis to annual
plants, which “advance continuously from seed to fructification.” Trees and other perenni-
als that produce seasonal fruits are excluded from his discussion. In addition, he excludes
all plants that required outside agents for pollination. Curiously, in view of Sprengel’s pio-
neering work on this subject, Goethe regarded examples of insect- or wind- mediated pol-
lination as “excrescences,” which are “abnormal” and “restricted” in nature. As discussed
later, neither wind nor insect pollination accorded well with his theory of “anastomosis,”
or re- fusion, which formed the basis of his view that plants are, by definition, self- sufficient
organisms.
Starting with the cotyledons, or seed leaves, Goethe traces the variations in leaf form
and size from node to node as the stem elongates. Goethe explains that the “cruder flu-
ids” of the sap are drawn off and replaced by “purer ones,” enabling the production of
the flower. Encouraged by the eighteenth- century discovery of spermatozoa in animals,
Goethe hazards the guess that petals may harbor male sperm, as suggested by their color
and scent. Such a proposal, he states, is consistent with the “close relationship of petals and
staminal organs,” as demonstrated by the presence of intermediate forms in some flow-
ers and the transformation of stamens into petals in double- flowers, a phenomenon that
results in sterility.