Josias Braun-Blanquet and the Sociology of Plants

Raunkiær based his system on the way plants have adapted to climate. Other botanists were using a similar approach to classify large units of vegetation, and one of the most influential was the German botanist and plant geographer August Grisebach. Other European plant ecologists developed Grisebach’s ideas. This led to the emergence of phytosociology as […]

Christen Raunkiær and the Way Plants Grow

In 1903 the Danish botanist Christen Raunkiær proposed a solution to the difficult botanical problem of comparing plant communities with entirely different compositions. Raunkiær’s idea was to categorize plants by the position of their perennating buds—the plant structure with which a plant survives periods of adverse conditions. Raunkiær believed that flowering plants first appeared in […]

Robert Brown, the Cell Nucleus, and the Study of Pollen

Charles Darwin’s theory of evolution by natural selection was first presented in the form of a paper read at a meeting of the Linnean Society in London on July 1, 1858. The meeting had been arranged hastily, following Darwin’s receipt on June 18 of a paper by Alfred Russel Wallace (1823–1913) setting out an almost identical […]

Matthias Schleiden, Theodor Schwann, and Cell Theory

It was Robert Hooke in the 17th century who first observed cells and gave them that name, but the German botanist Matthias Schleiden (1804–81) was the first scientist to appreciate their importance. All living organisms either consist of a single cell or are made up of cells, and organisms grow and reproduce by the division […]

Erasmus Darwin and The Botanic Garden

The Lunar Society boasted several members of outstanding intellect, who quite cheerfully referred to themselves as lunaticks. Joseph Priestley was one, and another was Erasmus, the grandfather of Charles Darwin. Erasmus Darwin (1731–1802) believed that in the natural world species were constantly developing as they struggled to overcome the constraints imposed by their environment. He […]


In 1667 the German chemist Johann Joachim Becher (1635–1682) published a book called Physica Subterranea (Physics below ground), in which he revised the traditional view of the classical elements. Becher replaced the elements fire and earth with three alternative forms of earth to which he gave Latin names: terra lapidea, or “stony earth,” which was […]

Joseph Priestley and “Dephlogisticated Air”

In 1772 William Petty, the second earl of Shelburne (1737–1805), invited Joseph Priestley (1733–1804), with his wife Mary and their three children, to live on his estate near Calne, Wiltshire, where Priestley would work as Petty’s librarian and tutor to his children. The Priestleys moved to the Shelburne estate the following year. That is where […]

Transpiration is the process by which the evaporation of moisture through leaf stomata generates a pressure that draws up moisture from the soil, through the roots and the plant’s xylem vessels.

Stephen Hales, the Movement of Sap, and Transpiration

On the surfaces of leaves there are small pores that open and close in response to the movements of two guard cells, one on either side of each pore. The pores are called stomata (singular stoma), and they are the openings through which the plant exchanges gases. Carbon dioxide enters the plant and is used […]

Robert Hooke and the Cell

In 1665 the English physicist, instrument maker, and inventor Robert Hooke (1635–1703) published a book called Micrographia describing his researches using a microscope and illustrated by his own excellent and detailed drawings. Hooke’s microscope has survived and is shown in the following illustration. It is now housed at the National Museum of Health and Medicine […]

Marcello Malpighi and the Microscopic Study of Plants

Nehemiah Grew moved from Coventry to London partly to gain access to the microscopes owned by the Royal Society. Scientists recognized the value of these instruments, and Grew made extensive use of them. It was the Italian physician Marcello Malpighi (1628–94), however, who really pioneered the use of the microscope in the study of anatomy. […]