Francis Rose

The 'Pevsner of plant-hunting' - a field botanist with a rare and intimate knowledge of the flora of Britain

Francis Rose, botanist: born London 29 September 1921; Lecturer in Botany, Bedford College, London 1952-64; Senior Lecturer in Biogeography, King's College London 1964-75, University Reader in Biogeography 1975-81; MBE 2000; married 1943 Pauline Arnup (three sons, one daughter); died Liss, Hampshire 15 July 2006.

Francis Rose was regarded by many as the greatest British field botanist of our time, possibly the greatest of the past century. He coupled an encyclopaedic knowledge of flowering plants, lichens and mosses with an exceptional sense of what might be called ecological awareness. Early on he acquired a knack for where "the best spots" were while walking, peering from the window of a speeding car or train, or even simply by studying a map. He has been called the Pevsner of plant-hunting.

Over a lifetime he worked out what it is that makes some botanical localities richer than others. He studied and compared the flora of woods of different ages. He recorded the flora of Kent, the Sussex Weald and parts of Hampshire in fine detail. And he was a master of what might be called plant geography, relating plants to their often subtle habitat condition defined by climate, rock type, soil and water, as well as present and past land-use.

Rose had an uncanny eye for revealing detail. He was an expert on small plants growing on bark and stone, and alert to their ecological significance. His surveys over the whole of Britain opened up new worlds for botanists, such as the tree-top jungles of lichens and mosses, or the tapestries of lichens on ancient buildings and gravestones. Few, if any, knew the flora of Britain so intimately. However his favourite stamping grounds were in the South, especially Kent, the Sussex Weald and the New Forest.

His early research work was on the ecology of lowland bogs. With the help of the young David Bellamy, then an unknown lab assistant, the two explored the physical and botanical characteristics of wet depressions in East Anglia; in 1960 they collaborated on a celebrated scientific paper, "The Waveney-Ouse Valley Fens of the Suffolk-Norfolk Border". Bellamy has always regarded Rose as his botanical mentor - as indeed have many others.

In the 1980s, with David Hawksworth, Rose was the first to demonstrate and map the effects of air pollution on lichens. He also pioneered the notion of "indicator species" of ancient woodland, which gave British conservationists a new perspective on the history and biology of natural habitats. In the process he overturned the accepted notion that "climax" forests of close-packed tall trees have the highest biodiversity. From studying lichens growing on trees he showed that in Britain "pasture woodlands" of stunted old trees growing in an open setting are much richer in species. Such discoveries demanded a fundamental reassessment of landscape history.

Rose was in demand as a lecturer - he was a gifted communicator and his lightly worn erudition, combined with a genial, gossipy, down-to-earth personality, was infectious. He wrote a number of books to help novice field botanists. In the pocket "Observer's Book" series, he revised for a new audience Ferns (1965), Grasses, Sedges and Rushes (1965), Butterflies (1974) and Wild Flowers (1974). His Wild Flower Key, first published in 1981, set new standards of accurate identification, enabling plants to be identified even when they were not in flower. The book, which took him 20 years to research and write, has never been out of print and was recently revised for a new generation by Clare O'Reilly. His other books include the beautifully illustrated Colour Identification Guide to Grasses, Sedges, Rushes and Ferns of the British Isles and North-Western Europe (1989). He was also co-author with Lady Anne Brewis and Peter Bowman of The Flora of Hampshire (1995), one of the most acclaimed local floras of recent times.

Born in the Kentish part of south London, Francis Rose first became interested in botany at the age of six, learning to identify wild plants on country walks with his naturalist grandfather. Biology was unfortunately not on the syllabus of his Roman Catholic school, Xavier College. Even so Francis managed to enrol at Chelsea Polytechnic and then at Queen Mary College, London, where he read Natural Sciences, graduating in botany. In 1953, he received his PhD for a field-based study of lowland bogs in Britain.

After wartime work testing explosives at Woolwich Arsenal, Francis Rose taught engineering science at Gravesend Technical School from 1944 to 1947. In that year he was appointed Lecturer in Botany at Sir John Lass College, and, two years later, at Bedford College, beginning a career-long association with London University. In 1964, he transferred to the university Geography Department as Senior Lecturer in Biogeography.

Being a lone botanist among geographers suited Rose's holistic approach to the environment. "Being a botanist in a geography department is unusual but advantageous," he once said. "It makes you the expert - and geographers are interested in climate, biogeography and all the strands that make up the environment." In 1975 a special post as University Reader in Biogeography was created for him at King's College London, which he occupied until retirement in 1981. He was also a popular tutor for field courses run by the Field Studies Council, and for extra-mural courses at the universities of Oxford and Bristol.

Rose was much involved in nature conservation work. He helped to found the Kent Field Club, and served as secretary and then chairman of the Kent Wildlife Trust in its early days. He was active in the British Bryological Society, the British Lichen Society and the Botanical Society of the British Isles, and was elected as a life member of all three, the only British botanist to be so honoured.

Much of his fieldwork was written up in over 60 detailed reports for the Nature Conservancy Council and other bodies. He had a rare ability to describe a habitat in the round as well as in detail, and in language that appealed to the field naturalist as well as to specialists and conservation bureaucrats.

His immense collection of notebooks forms a unique archive of detailed information on plants and vegetation from the 1940s onwards. Many of them have been transcribed on a computer archive at Sussex University for use in biological monitoring. The originals, together with Rose's herbarium of more than 20,000 specimens of mosses, lichens and vascular plants, are at the National Museum of Wales and in local museums, as is his photo-library of 5,000 slides.

From the 1970s onwards, Rose lived at Liss in rural Hampshire with his wife, Pauline, whom he married in 1943. In 2000 he was appointed MBE for services to botany, and the Wildlife Trust's Christopher Cadbury Medal the following year. In 2003, the Francis Rose Reserve was set up by the Royal Botanical Gardens at Wakehurst Place in West Sussex, in an area rich in Roses's favourite lichens, mosses and filmy-ferns.

His name also lives on in several species of lichens, including Porina rosei or "Francis's Blue-green Lichen".

Peter Marren