Célestin Alfred Cogniaux

Célestin Alfred Cogniaux (1841-1916) was a Belgian botanist who was born in the village of Robechies. He stood out for his study of cucurbits, melastomes, and orchids, and with these families he was the author who contributed the most pages to Flora Brasilienses.

A promising student from the start, he graduated from the École Normale de Nivelles, where he received a teaching diploma at the age of 22.

His first scientific article, about the alga Nitella tenuissima, appeared in the Bulletin de la Société Royale Botanique de Belgique in 1863. Cogniaux’s subsequent detailed floral descriptions, with many measurements, may relate to this initial focus on more basal plants.

In the following 10 years Cogniaux taught at five different schools, until 1872 when he was offered a research position at the National Botanic Garden of Belgium due to the influence of his friend and mentor, the botanist turned politician Barthélemy Dumortier.

That year, August Wilhelm Eichler, editor of Flora Brasiliensis, had asked the Belgians to contribute, if possible, studies of some of the ‘remaining’ families, including Melastomataceae and Cucurbitaceae.

Although Cogniaux immediately signed up for melastomes, it seems that Eichler was somewhat skeptical and suggested the young man do the cucurbits first. The study of this family for Brazil (1878) and then for the world (1881) received international acceptance.

After that, Cogniaux produced studies of the Melastomataceae for Flora Brasiliensis (1883-1888) and for Monographiae phanerogamarum (1891), in which 2,731 species and 555 varieties are reviewed, 793 of them new to science.

Disagreements, the nature of which is unclear, led Cogniaux to resign from the Botanic Garden in 1880, aged 39, and return to teaching, which he pursued until his retirement in 1901, while continuing his systematic studies.

From 1887 to 1902, Cogniaux was vice-consul of Brazil in the Belgian city of Verviers. He was appointed to this position by Dom Pedro II, who had met him in Europe and already admired him for his contributions to Flora Brasiliensis. This work was dedicated to the emperor by its authors.

Until the day of his death aged 75 on April 15, 1916, Cogniaux worked on contributions on melastomes and cucurbits for various floras and on a world monograph on orchids.

Although the excellence of his work was widely recognized and brought him international acclaim, Cogniaux always remained a quiet and unassuming man. After his death, his private herbarium, with 5,251 specimens, was donated to the Meise Botanic Garden. 

The orchid genus Neocogniauxia was thus named in his honor by Rudolf Schlechter. Henri Ernest Baillon named the genus Cogniauxia (Cucurbitaceae) and Carl Ernst Otto Kuntze named the fungal genus Biscogniauxia (Xylariaceae) in his honor.