In 1751, Carl Linnaeus completed a book elaborating principles of botany that he had developed as a young man and published in Holland 15 years before. This new Philosophia Botanica, shorter than he had planned because of his battles with gout, became one of the most important books in the history of systematic botany.

The Philosophia is “the first textbook of descriptive systematic botany and botanical Latin” (Stearn, 1992, p. 35). It summarizes Linnaeus’s practices, which were already affecting systematic botany in Europe. It defines and illustrates the terms Linnaeus used for the parts of plants; it lays out his methods for accurately and concisely describing plants; and it gives the rules by which he selected names for genera, species, and other groups of plants.

Besides these practical aspects, the Philosophia is also a comprehensive textbook of the theoretical botany of Linnaeus’s time (Stafleu, 1971). It presents theories of life, of the origin of species, of reproduction. It lays out the Aristotelian base for Linnaeus’s method of describing and naming plants.

Today the Philosophia is probably most memorable for the first appearance in print of the term nomina trivialia for one-word tags that, tacked on to a genus name, made it easy to remember and talk about plant species. These trivial names became the specific epithets of today’s binominal species names—the only surviving vestige of the Linnaean system of nomenclature. (See for example Heller, 1964; Stafleu, 1971, pp. 103-112).

But the Philosophia is also fascinating for the innumerable bits of practical information and advice scattered throughout the text: How to press and mount plants and make a herbarium; what a botanical novice should know; what clothes one should wear on botanical excursions; what plants grow in different habitats, an early description of ecological communities; how long is a thumb (pollex); what time of day flowers of various species open and close; what wars were fought over plants; that orchids are aphrodisiac.

The short sentences, the variously indented paragraphs suggesting an outline, and the lists and tables give to the whole work the feel of lecture notes. It comes as no surprise that Soulsby (1933, sub no. 441) says “its substance formed the subject of Linnaeus’s botanical lectures for 1746-48.”

Nearly every aphorism in the Philosophia refers to others. These elaborate cross-references, with the brevity of most of the sections, make the Philosophia an ideal hypertext document.