Theophrastus. History of Plants
These books discuss the main parts of plants, with Theophrastus distinguishing between external and internal parts.
The external parts are roots, stems, branches and shoots, leaves, flowers, and fruits. The seed is considered by Theophrastus, as by his predecessors, as the “egg” of plants, but he did not know what the connection between the seed and the flower was.
The internal parts of plants are bark, wood, and pith, which, in turn, consist of sap, fibers, veins, and flesh.
What Theophrastus meant by this is not entirely clear. Sap is, in some cases, latex, and in others something else, such as resin or gum. Fibers and veins are named so for their similarity to the corresponding parts of animals.
The difference between fibers and veins is that fibers do not branch. Theophrastus referred to bundles of thick-walled phloem as fibers, but in other cases, apparently also to vascular bundles, for example, in leaves.
Veins are branched tubes filled with sap: lactifers, resin canals, ducts, and again vascular bundles.
Interestingly, the terms “veining,” “veins,” and “nerves” of leaves are still used in botany: intriguing echoes of terms that have lost their direct meaning from scientific antiquity.
Finally, the flesh is located between the fibers and veins and is characterized by being divisible in all directions, while fibers split only along their length.
In various combinations, these 4 main or primary parts form the pith, wood, and bark.
The external parts of plants are characterized with examples and quite in detail.
The classification and system of plants by Theophrastus is very simple: he first divides the entire plant kingdom into 4 sections: trees, shrubs, perennials, and herbs, and within each section distinguishes two groups: wild and cultivated plants. He then describes trees and shrubs, primarily Greek, but also foreign, addressing many important theoretical and practical issues, discussing natural and artificial reproduction of plants, woods from a technical perspective, methods of seed dispersal, even artificial pollination, and elaborating on longevity, diseases, and death of plants.
When it comes to perennials, Theophrastus first describes wild ones (which are divided into 2 categories – with “thorns” and “without thorns”), then cultivated ones: “plants for wreaths,” i.e., garden flowers, and ornamental plants. This group includes roses and annual herbs according to Theophrastus.
Two books of the work are dedicated to herbs, mainly cereal grains, legumes, vegetables, etc. In total, Theophrastus identified about 500 species of plants, including ferns, fungi, and algae (notably, he was aware of not only Mediterranean algae but also large forms from the Atlantic, presumably laminaria).
Speaking generally, Theophrastus’s descriptions of plants are brief and not sufficiently clear, making it difficult in most cases to guess which specific plant is being referred to.
The last (9th) book of “Natural History,” which is sometimes considered a separate work of Theophrastus, discusses specific saps and the healing powers of roots.