Flora Unveiled

464 i Flora Unveiled

What Wiegmann had accomplished, however, made him a worthy recipient of the
prize. Henschell had claimed that Koelreuter’s methodology was flawed because the plants
he used were grown in pots, which cramped their roots. As a result, Henschell asserted,
monstrous offspring had been produced, which Koelreuter had misinterpreted as hybrid
plants. Koelreuter had probably grown his plants in pots for convenience, since he had to
emasculate the flowers to prevent self- pollination. To circumvent Henschell’s criticism,
Wiegmann, then in his early fifties, grew all his plants in the open ground— despite, he
complained piteously in his report, “weak sight, a trembling hand, and painful bending and
k neeling.”^5 However, his perseverance paid off. At the end of four years, he had performed
thirty- six crosses and confirmed Koelreuter’s major findings. Because the plants were grown
in open soil, the argument could no longer be made that Koelreuter’s hybrids had actually
been “monsters” caused by pinched roots.
Henschell had also claimed that the fertility of many of Koelreuter’s interspecies hybrids
were proof that they were not true hybrids, since it was well- documented that hybrids in
the animal kingdom were sterile. However, Wiegmann obtained the same results that
Koelreuter did:

I have found his observations well- founded, that the plants produced from seed from

one capsule of hybrid plants, often differ from one another with respect to fertility,

and especially in the structure of certain parts, now approximating more to the father,

now to the mother.^6

Having demonstrated that he could repeat virtually all of Koelreuter’s results in plants
grown under field conditions, there could no longer be any doubt that plants could form
hybrids in accordance with the sexual theory. It seems likely that Goethe, a voracious
reader, had kept abreast of the results of the Prussian Academy’s contest and was aware of
Wiegmann’s prize- winning study. In 1831, the same year that Wiegmann’s essay was pub-
lished, he acknowledged Henschell’s— and by association Schelver’s— stinging defeat.
Two years later, the Dutch Academy of Sciences offered another prize to answer addi-
tional questions about plant hybridization raised by Wiegmann’s studies:  “What does
experience teach regarding the production of new species and varieties through artificial
fertilization of flowers of the one with the pollen of the other, and what economic and orna-
mental plants can be produced and multiplied this way?” No doubt the thriving Dutch tulip
industry, eager to apply the new technique of cross- pollination to the creation of profitable
new tulip varieties, was behind the new prize. In any case, the question of plant hybridiza-
tion had now moved beyond whether it occurred to how it could be exploited commercially.
To the surprise of no one, the winner of the Dutch prize was the German physician Carl
Friedrich von Gaertner, the celebrated son of the noted botanist Joseph Gaertner, whose
extensive work on plant hybridization was already well- known to members of the Dutch
Academy. The research for which Gaertner was awarded the prize in 1837 had been con-
ducted over the previous twenty- five years and involved nearly 10,000 crossing experiments
among 700 species belonging to 80 different genera. By the end of his career, Gaertner had
obtained some 350 different hybrid plants, far more than Koelreuter and Wiegmann com-
bined. These results were ultimately published in 1849, in an updated edition of his book,
Experiments and Observations on the Production of Hybrids in the Plant Kingdom.^7