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interpreted them as a waste product. Using the analogy of earwax in animals, which he
defined as an impurity of the blood secreted by the brain, he referred to pollen as particles
of “wax” released by stamens during the removal of the impurities from the plant’s earthy
nutriment.
Albert thus considered the function of stamens to be excretion rather than reproduction.
Why didn’t Albert, who must have been familiar with the ancient literature on the artificial
pollination of female date palms, connect the “dust” of male date palms with the “wax” of
stamens? The answer is that he was merely following Aristotle.
Although Albert adopted Aristotle’s erroneous identification of pollen as “wax” and
embellished it further by comparing it to earwax, to his credit, he also performed the first
known chemical tests on it, such as placing it in a flame. He interpreted the fact that pollen
readily ignited as a confirmation that it was composed of wax. Indeed, Albert was partially
correct in his conclusion because the major component of the outer layer of pollen cell
walls is a highly cross- linked lipid compound with a waxy consistency called sporopollenin.
Albert also adopted Aristotle’s notion that bees collect wax from flowers to build their
hives. In reality, worker bees secrete the wax themselves in specialized glands located on
their abdomens. Pollen serves as a nutritious food source for bees, not as a direct source
of wax.
With De Vegetabilibus, medieval botany reached its apex, but in most respects it fell far
short of the standard set by Theophrastus. Theophrastus did not have to contend with the
philosophical disdain for “particulars” in the study of nature as Albert did. So pervasive
was this disdain for “particulars” in the medieval period that Albert felt the need to apolo-
gize in De Vegetabilibus for his descriptions of individual plants.^52 Not until 1453, with the
appearance of the Latin translations of the long- lost botanical treatises of Theophrastus,
did such detrimental medieval attitudes finally die out. Remarkably, Historia Plantarum
and De Causis Plantarum were still scientifically useful some 1,600 years after they were
written.The Rebirth of Naturalism in Medieval Herbals
The natural theology of St. Francis and the poems of the Troubadours in the thirteenth
century laid the foundation for the revival of classical naturalism in art. In France and
Germany, exquisite foliage motifs began appearing on the capitals of the major cathedrals.
Still, the plant illustrations of the herbals remained highly stylized until the end of the four-
teenth century, when professors of the newly established medical schools began to demand
greater accuracy.^53
The revival of Naturalism in the manuscript herbals took place over a period of about
seventy years in the fourteenth century. The Tractatus de Herbis, written early in the four-
teenth century, included both highly stylized illustrations copied from older herbals as well
as some that were apparently drawn from real plant material. An example of the latter is
the portrait of jasmine shown on the right in Figure 11.5A. Here, we see the beginnings of
realism, although not on a par with the best plant portraits in the sixth- century Juliana
Anicia Codex. The specimen is unnaturally flattened, as if the portrait had been drawn from
a pressed plant with its leaves carefully spread out.
Fully naturalistic plant portraits begin to appear in the manuscript herbals at the end of
the fourteenth century. The first of these was the Herbolario Volgare (Popular Herbal), an