Flora Unveiled

342 i Flora Unveiled

plants were filled with sterile seeds. But his happiness was cut short by the discovery that
among the mostly sterile seeds were “numerous fertile seeds”— he does not say how many—
”at which,” he confessed rather endearingly, “I must admit I was quite upset.”
Whenever Camerarius’s confidence wavered, he turned to the philosophical writings of
Robert Boyle for solace. Following the distressing results with Cannabis, he seized upon
a particular passage admonishing young scientists never to trust the outcomes of single
experiments:

Experiments on the basis of which you strongly desire to erect theories ... should be

verified repeatedly, and with the greatest of circumspection; nor should too much

credence be given to those that you accomplish perfectly no more than a single time.^50

Buoyed by Boyle’s reassuring words, Camerarius determined to repeat the Cannabis
experiment the following spring, but, when spring arrived, he was stricken with a serous
illness that lasted until the summer. By the time he recovered, it was too late in the growing
season to begin a new experiment. Fortunately, Camerarius discovered an isolated group of
six Cannabis plants growing in his garden, three of which were females.^51 The plants were a
little taller than he would have preferred, but none of the anthers of the three male plants
had split open yet, which meant that there was still time to conduct his experiment. He
quickly cut down the males and waited anxiously to see how the females would be affected.
Alas, he obtained the same result as before! Although each of the female plants contained
“an immense quantity of infertile seeds,” there were in addition, he sadly confessed, “fertile
ones that were not so few in number.”
Despite the equivocal results with Cannabis, Camerarius persevered with other species.
He conducted similar experiments with two monoecious plants: castor bean (Ricinus) and
maize (Zea mays). After removing the male flowers from castor bean plants, he waited to see
what would happen to the female flowers. To his immense relief, not one pistil developed
into a mature fruit:

In the second class of plants, in which the male flowers are separated from the female

on the same plant, I have learned by two examples the deleterious effect produced by

removing the anthers. When I  removed the male flower buds of Ricinus before the

anthers had expanded, and prevented the growth of the younger ones, but preserved

the ovaries that were already formed, I  never obtained perfect seeds, but observed

empty vessels, which fell finally to the ground exhausted and dried up.^52

Turning to maize, Camerarius identified the tassels at the top of the stalk as male inflo-
rescences and the cobs below as females. Camerarius also observed the silky styles attached
to each kernel and noted that they functioned to receive the pollen:

In this cereal the protruding tassel at the end of the stalk is too well known to need

a detailed description. After the wilting and drying of these tassels without produc-

ing any seeds themselves, farther down those thick cylindrical cobs are taking shape,

which with their grains are covered by some leaves and protruding from each grain a

long thread [silk], which spread like a tail and which receive the pollen.^53