Flora Unveiled

214 i Flora Unveiled

into a scheme including the four elements and the four qualities of matter (Figure 8.1). This
scheme was used by Aristotle to arrange all organisms into a hierarchy, from primitive (cold/
moist) to advanced (hot/ dry), and to differentiate between the sexes.^12 In general, things that
were hot and dry, like the sun, were considered superior to things that were cold and wet,
like the earth. His hierarchy of Nature placed cold/ wet organisms at the bottom (plants and
invertebrate animals) and hot/ dry organisms at the top (quadruped mammals and humans).

Aristotle on Sex, Gender, and Plants

What set Aristotle apart from his intellectual forebears was the vast scope of his investiga-
tions and his preference for direct observation as the surest way to discover nature’s secrets.
Nowhere were these qualities more on display than in his biological treatises. Aristotle was
the first to study living organisms in a systematic way, from their behaviors in the field to
their internal anatomy.
Because Aristotle was primarily interested in animals, it was left to his student and col-
league, Theophrastus, to apply his mentor’s meticulous methods to plants. Together, they
collected and systematized a prodigious body of biological knowledge, supplementing their
own observations with reports from a wide range of informants, including farmers, rhizo-
tomai (herbalists), woodsmen, fishermen, and craftspeople. They also incorporated reports
from far- flung regions of the Hellenistic world sent back to them by scientific observers,
many of whom were undoubtedly their own students accompanying Alexander’s army.
But despite their considerable resources, neither Aristotle nor Theophrastus succeeded
in advancing the problem of sex in plants much beyond what ancient Mesopotamians had
learned through their mastery of artificial pollination in dioecious date palms and the use
of the caprifig and fig wasp to pollinate edible figs. The failure of these two luminaries to
recognize the more general role of pollination in hermaphroditic flowers has long puzzled
historians of botany.
Whereas Aristotle’s celebrated teacher, Plato, had viewed the physical world as mere
“shadows” of a perfect celestial plain, knowable only through mathematics and abstract phi-
losophy, Aristotle and Theophrastus regarded everything in the natural world that could
be perceived by the senses as both real and knowable. Both believed that direct observation

Yellow Bile

EARTH

dry

Black Bile

WATER

cold

DRY, CO

LD

CO

LD, MO

MOIS IST

T, HO

T

HO

T, DR

Y

AIR

moist

FIRE

hot

Blood Phlegm

Figure 8.1 Diagram of the four humors in relation to the four elements and properties of matter.