ARTHUR EXELL was an outstanding personality in the field of systematic botany and phytogeography this century. Despite his formidable list of publications, he cannot be credited with new scientific ideas or systems, but his greatest achievement lies in the furthering of botanical exploration in tropical and sub-tropical Africa, and above all in organising international scientific co- operation with consummate skill.
Exell stood out from most of his colleagues - often competent, but tedious specialists - as a man of culture with a natural talent for making friends. Unusual for an English scientist, he acquired more than a working knowledge of the main Western European languages. He was able to deliver off-the-cuff speeches at international conferences in French, German and, above all, Portuguese, and was steeped in their literature; he prided himself on having read Dante in Italian.
He spent an inordinate amount of his modest income in hospitality to foreign colleagues, to the point of providing them with stationery and postage stamps on the bedside table. Kindred spirits would find themselves sitting into the early hours opposite him at the chessboard. But despite his gregariousness, and for all his kindness, he could be a nervous, impatient and shy character.
Exell was educated at Queen Elizabeth Grammar School, Warwickshire, and King Edmund's School, Birmingham, from which he went up as a scholar to Emmanuel College, Cambridge. In 1924 he won in open competition a place in the Department of Botany at the British Museum (later the Natural History Museum). He was employed in the Herbarium - one of the greatest collections of conserved plants in the world - where he was responsible for a group of plants known as the Polypetalae. His first scientific publication was a morphological study of the hymenium (the skin) in three species of mushroom, but a glance at his long list of publications revealed how quickly he got to grips with the systematic complexities of the families of flowering plants under his care.
He made his mark with studies of the Combretaceae - a large family of tropical and sub- tropical trees and shrubs - becoming the world authority on the subject. A lesser man might have dedicated his entire career to these and related plants, but he soon broke out of the confines of Herbarium investigations and became involved in the floristic exploration of vast areas of Africa. His interest in this direction was triggered by the arrival at the museum of substantial collections made by the botanists and explorers F. Welwitsch, John Gossweiler and others.
Like all scientists of the British Museum, he was in a privileged position. He once remarked, 'One feels as proud as a priest who has been accredited to the Vatican; anyone who has a name in our field of science will sooner or later pay us a visit.' By his nature and his gift for communication he made good use of his opportunity, but he also visited other great centres of systematic botany, especially Berlin, Paris and Brussels.
In his first foray into Africa Exell spent many months in the botanically underexplored islands of the Gulf of Guinea, where he made extensive collections in S. Tome, Principe, Fernando Po and Annobon. The scientific results of this expedition, as well as earlier ones by other travellers, were published by Exell in his Catalogue of the Vascular Plants of S. Tome (1944). With its later amendments, it represents a milestone in African botany and is the definitive work.
These activities brought Exell into close touch with the Portuguese, who had colonised the islands as early as the 15th century. It was these contacts, especially with Professor Carrissoof Coimbra Universityand Dr SA Mendonca, which determined his subsequent career. With these two men, his wife and John Gossweiler, he embarked on a floristic exploration of the flora of the Portuguese colony of Angola, a rather traumatic experience since in the course of it Carrisso died of a heart attack. Based on this and other missions, there emerged Part One of the Conspectus Florae Angolensis, published jointly with the British Museum in 1937. The work is still in progress. In 1938, to Exell's great disappointment, the ancient university of Coimbra awarded an honorary degree to his superior, J. Ramsbottom, then Keeper of Botany.
The Second World War interrupted Exell's career and he was sent 'on loan' to the Foreign Office, working until 1950 in the Government Communications Headquarters at Bletchley Park, mostly occupying the 'Portuguese Desk' (as far as it is known), and at some stage worked at Cheltenham as a decoder.
After his apparently reluctant return to his old post at the British Museum (NH), he set in motion two projects which he had had in mind for years. The first was the establishment of an international organisation of botanists interested in the exploration of Africa. With his diplomatic skills and endless efforts he succeeded in founding in Brussels in 1951 the Association pour l'Etude Taxonomique de la Flore d'Afrique Tropicale (AETFAT). .
His second project was exploration of the flora of the area of south tropical Africa drained by the River Zambesi, resulting in Flora Zambesiaca, planned as a 12-volume work. The area comprised the then Federation of Rhodesia and Nyasaland, Bechuanaland, the Caprivistrip of Namibia and Mozambique. This major undertaking, originally financed by the British and Portuguese governments and the federation, has survived all the vicissitudes and political changes of recent decades (the first volume appeared in 1960) and is now about 60 per cent complete.
It was not until 1962 that the University of Coimbra, at the instigation of Professor Abilio Fernandes, awarded him the degree of Doctor of Science. In 1971 the Portuguese government conferred on him the decoration of Comendador Da Ordem De Santiago da Espada.
Arthur Exell retired from the British Museum (NH) - now, to his great sadness, renamed the Natural History Museum - as Deputy Keeper of Botany in 1962, having been previously bypassed for the Keepership. After this, mainly working from home, he had part-time employment with the Royal Botanic Garden, Kew. On retirement, he and his wife set up home in the village of Blockley in the Cotswolds, where he spent many happy years actively involved in local affairs. The most appealing achievement of his latter years is a light-hearted yet scholarly small book on the ladybird, giving the popular names of this small beetle in many languages and cultures.