Flora Unveiled

220 i Flora Unveiled

God next commands “every living thing that moveth” (animals) to “be fruitful and mul-
tiply.” In contrast, plants are not encouraged to “multiply,” apparently because there is no
need— they already contain the seeds of the next generation within themselves:

See, I have given you every plant bearing seed that is upon the face of all the earth, and

every tree with seed in its fruit; you shall have them for food.^29

Plants are exempted from the divine command to “multiply” because plants were thought
to produce seeds asexually.

Theophrastus on Plant Sex

We now turn to the writings of Aristotle’s most famous pupil, Theophrastus, whose botani-
cal works represent the first comprehensive treatises on plants. Fortunately, Theophrastus’s
writings about plants have come down to us relatively intact, allowing us to reconstruct his
thinking on the subject in some detail. Two of his botanical works have survived: Historia
Plantarum and De Causis Plantarum.
Theophrastus’s conception of plants differed from those of Aristotle in many respects.
Most importantly, he did not consider plants to be merely degenerate forms of animals, as
implied by Aristotle’s Scala Natura. He argued that the anatomy, growth, and reproduction
of plants were qualitatively different from those of animals. He rejected the idea that the
root could be compared to the mouth and digestive system of animals. Because of the many
differences between plants and animals, Theophrastus warned against trying to draw analo-
gies between two qualitatively different types of organisms.
Although Theophrastus’s views on sex in plants are basically similar to those of Aristotle,
he studied plants in far greater depth and detail than did his mentor. For example, he wrote
extensively about plant anatomy and developed a general system of classification based on three
main groupings: herbs, shrubs, and trees. Trees, perhaps because of their size, were considered
to be the most advanced. He also distinguished between plants based on the structures of their
flowers, anticipating the Linnean sexual system of classification. However, Theophrastus’s defi-
nition of the flower was restricted to the sepals, petals, and probably the stamens:

Thus of flowers some are downy, as that of the vine mulberry and ivy, some are leafy,

as in almond, apple, pear, and plum. Again some of these flowers are conspicuous,

while that of the olive, though it is leafy, is inconspicuous. Again it is in annual and

herbaceous plants alike that we find some leafy, some downy.^30

He regarded the carpel, or pistil, as a structure separate from the flower that developed
into the fruit, and he associated the persistence of the pistil after the corollas had been shed
with higher crop yields:

[T] here are ... differences in the way of growth and the position of the flower

[corolla]; some plants have it close above the fruit [pistil], as vine and olive; in the lat-

ter, when the flowers [petals] drop off, they are seen to have a hole through them, and