The Pteridologists of Flora Brasiliensis

John Gilbert Baker (1834–1920) was born in Yorkshire, England. He worked at the Royal Botanic Gardens, Kew, where he served as herbarium curator from 1890 to 1899. In Flora Brasiliensis, he revised Cyatheaceae and Polypodiaceae, which then encompassed nearly all ferns, including tree ferns (Cyathea). Besides ferns, Baker also wrote treatments for flowering plant families, such as Asteraceae and Connaraceae. His work was essential for the classification of tropical flora.

Friedrich Adalbert Maximilian Kuhn (1842–1894) was born in Berlin, where he studied botany with J. Hanstein, H. Karsten, and A. Braun. He worked at the Berlin Royal Herbarium and taught for decades. In Flora Brasiliensis, he described the families Isoëtaceae, Marsileaceae, and Salviniaceae. Isoëtaceae are aquatic lycophytes with globose stems and cylindrical leaves. Marsileaceae and Salviniaceae are heterosporous ferns: the former resemble four-leaf clovers, while the latter float in lakes and rivers.

Carl August Julius Milde (1824–1871), a German botanist, was born in Breslau (now Wrocław, Poland). He was responsible for the family Equisetaceae, which includes horsetails. This plant group is characterized by hollow, jointed stems, reduced leaves, terminal strobili, and spores with hygroscopic elaters that aid in dispersal. For a long time, horsetails were considered a separate group from ferns due to their unique morphology.

Anton Friedrich Spring (1814–1872) was born in Geroldsbach, Bavaria. He studied medicine and botany at the University of Munich under the guidance of Martius. He taught physiology and anatomy at the University of Liège and was a member of the Belgian Academy. In Flora Brasiliensis, he described Lycopodiaceae, Selaginellaceae, and Psilotaceae, groups that share some morphological similarities but belong to entirely different lineages: the first two are lycophytes, while the last is a fern.

Johann Wilhelm Sturm (1808–1865) was born in Nuremberg, Bavaria. Son of Jacob Sturm, a renowned engraver and entomologist, he studied botany after graduating from his hometown’s School of Arts. He helped illustrate scientific works and received an honorary doctorate from the University of Pennsylvania. In Flora Brasiliensis, he described Ophioglossaceae and Marattiaceae (eusporangiate ferns) and Osmundaceae, Schizaeaceae, Gleicheniaceae, and Hymenophyllaceae (basal leptosporangiate ferns).

Carl Friedrich Philipp von Martius (1794–1868) was born in Erlangen, Germany. Between 1817 and 1820, he explored Brazil on a scientific expedition, collecting thousands of plants that later formed the basis of Flora Brasiliensis. Although he did not describe ferns and lycophytes directly in this work, he published studies on these groups in Icones Plantarum Cryptogamicarum (1828–1834), in collaboration with Hugo von Mohl, providing detailed descriptions and illustrations.

Hugo von Mohl (1805–1872) was a German botanist and a pioneer in plant anatomy. Although he did not contribute to Flora Brasiliensis, he collaborated with Martius on Icones Plantarum Cryptogamicarum (1828–1834), describing the anatomy of tree ferns. He was also the first to describe chloroplasts (1837) and coined the term "protoplasm" (1846), revolutionizing cell studies. His work contributed significantly to understanding cell division and plant structure.