Johann Jacob Paul Moldenhawer (11 February 1766 – 21 August 1827) was a German

botanist Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...

who made a number of important discoveries in

plant anatomy Plant anatomy or phytotomy is the general term for the study of the internal Anatomy, structure of plants. Originally, it included plant morphology, the description of the physical form and external structure of plants, but since the mid-20th centu ...

. He was born in

Hamburg Hamburg (, ; ), officially the Free and Hanseatic City of Hamburg,. is the List of cities in Germany by population, second-largest city in Germany after Berlin and List of cities in the European Union by population within city limits, 7th-lar ...

, the son of a minister, and started out studying theology and the classics. At some unknown point he became interested in plants, and in 1791 he published ''Tentamen in historiam plantarum Theophrasti'', on

Theophrastus Theophrastus (; ; c. 371 – c. 287 BC) was an ancient Greek Philosophy, philosopher and Natural history, naturalist. A native of Eresos in Lesbos, he was Aristotle's close colleague and successor as head of the Lyceum (classical), Lyceum, the ...

, and the following year he is recorded as "Extraordinary Professor of Botany and Fruit Tree Culture" (''außerordentlicher Professor für Botanik und Obstbau'') at the

University of Kiel Kiel University, officially the Christian Albrecht University of Kiel, (, abbreviated CAU, known informally as Christiana Albertina) is a public research university in the city of Kiel, Germany. It was founded in 1665 as the ''Academia Holsator ...

. He studied plant anatomy from 1795 until 1812, when he published ''Beyträge zur Anatomie der Pflanzen'' on his results. Immediately subsequently he concentrated on

fruit tree A fruit tree is a tree which bears fruit that is consumed or used by animals and humans. All trees that are flowering plants produce fruit, which are the ripened ovaries of flowers containing one or more seeds. In horticultural usage, the te ...

culture. He died in

Kiel Kiel ( ; ) is the capital and most populous city in the northern Germany, German state of Schleswig-Holstein. With a population of around 250,000, it is Germany's largest city on the Baltic Sea. It is located on the Kieler Förde inlet of the Ba ...

. Moldenhawer's contributions center on the microscopic examination of plant tissues, for which he devised techniques to separate the cells from the middle lamella layer that separates them. He identified

vascular Vascular can refer to: * blood vessels, the vascular system in animals * vascular tissue Vascular tissue is a complex transporting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue ...

and

parenchymatous upright=1.6, Lung parenchyma showing damage due to large subpleural bullae. Parenchyma () is the bulk of functional substance in an animal organ such as the brain or lungs, or a structure such as a tumour. In zoology, it is the tissue that ...

tissues, described

vascular bundles A vascular bundle is a part of the transport system in vascular plants. The transport itself happens in the stem, which exists in two forms: xylem and phloem. Both these tissues are present in a vascular bundle, which in addition will includ ...

, observed the cells in the

cambium A cambium (: cambiums or cambia), in plants, is a tissue layer that provides partially undifferentiated cells for plant growth. It is found in the area between xylem and phloem. A cambium can also be defined as a cellular plant tissue from whic ...

, and interpreted

tree ring Dendrochronology (or tree-ring dating) is the scientific method of dating tree rings (also called growth rings) to the exact year they were formed in a tree. As well as dating them, this can give data for dendroclimatology, the study of climate ...

s. He found that

stomata In botany, a stoma (: stomata, from Greek ''στόμα'', "mouth"), also called a stomate (: stomates), is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange between the internal air spa ...

were composed pairs of cells, rather than a single cell with a hole. Although Moldenhawer is not credited with the

cell theory In biology, cell theory is a scientific theory first formulated in the mid-nineteenth century, that living organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pr ...

, his work provided key documentation for the validity of the theory in plants. The genus '' Moldenhawera'' is named in his honor.

References

* Duane Isely, ''One hundred and one botanists'' (Iowa State University Press, 1994), pp. 127–128 1766 births 1827 deaths 18th-century German botanists Scientists from Hamburg University of Kiel alumni Academic staff of the University of Kiel 19th-century German botanists {{Germany-botanist-stub