JARS v48n1 - The Loss of Dr. Sleumer

The Loss of Dr. Sleumer
Frank Doleshy
Seattle, Washington

Bordered in gray, a note arrived in early October from Prof. Dr. Hermann Otto Sleumer's daughter Angela and granddaughter Nora, telling us he had died on October 1st, 87 years old. Thus we lost the ARS Gold Medalist who had set off two revolutions. First, he had developed a logical system of distinguishing features for all kinds of rhododendron species, enabling us to identify them without knowing which of the old-fashioned "series" they are in. Second, he had decided the not-too-well-known tropical species needed some personal visits, and he did much to get them into cultivation.

As background for becoming such a scientific revolutionary, Dr. Sleumer first followed his father into pharmacy, then worked at this during weekends and holidays to support his study of botany, obtaining a doctorate in 1932. In 1933 he joined the great Berlin-Dahlem botanical center, where he did the scientific work on 32 plant families, one being Ericaceae (including Rhododendron ), and he worked so rapidly that he published six to 14 papers per year. However, unhappy with Hitlerdom, he refused to join the Nazi party and therefore did not receive a permanent academic position, but nevertheless was in the German army 1941-44, mainly as a pharmacist. Returning to Berlin after the war, he found the botanical center mostly demolished and his home an unlivable mess after being used as Russian officers' quarters. He joined in the tasks of rehabilitation and also was invited to take two additional faculty positions. Yet he could foresee nothing ahead in Berlin but 20 years of rebuilding, with little chance to get to the scientific frontiers that were his joy.

This dreary period ended with an offer from the University of Tucuman in Argentina, where he could return to taxonomic research and exploration. He accepted and went there in September 1949, on contract for three to six years, while a position was held open for him in Berlin until 1952, with the prospect of his becoming director. Despite this somewhat tentative approach to his Tucuman appointment, much about it was attractive to him; he readily learned Spanish and explored the plant life of the Andes, between Patagonia and Bolivia. Yet, with South American changes in politics and economics, the opportunities declined there. Consequently he moved to the Netherlands, and in 1953 he joined the staff of Foundation Flora Malesiana, centered at Leiden as a guest working group. This foundation's great project was and is a systematic study of the plants found from New Guinea west through Sumatra and the Indochinese Peninsula, and from the Indies north through the Philippines. Then in 1956 Sleumer accepted a permanent post at the Rijksherbarium in Leiden, with the condition that he continue his work for Flora Malesiana.

Turning now to the fortunate relationship between Sleumer and the Seattle Rhododendron Society, Mrs. Doleshy found that the University of Washington library had a German language copy of his then-not-translated new classification system. Delighted with this, we wrote him and learned he would soon leave on his 1961-62 New Guinea expedition, emphasizing rhododendrons. Our SRS Species Study Group decided to provide some financial support for this, and we soon started receiving numerous seeds and cuttings. These amazed the federal plant quarantine people in Seattle, who called us whenever they came in and then even hand-delivered them the same day to downtown offices. Our propagating techniques were very experimental, but we learned, and I'm sure these particular seeds and cuttings were the source of many plants now alive and growing. Reflecting his own enthusiasm, Sleumer even pressed flowers with a fairly cool iron to mail us while the colors were still vivid. Commonly, the huge-flowered R. leucogigas is considered his prize find, but I'd nominate his new collection of R. phaeochitum , found as an epiphyte, rooted among the branches of a newly felled tree. This has a conspicuous brown indumentum (of scales, not hairs); it produces its good-sized shell-pink tubular flowers for months at a time, and it layers itself wherever it can.

Sleumer's work on rhododendrons and other plants has appeared in the continuing series of periodically issued publications titled Flora Malesiana , but a subscription to the whole series is costly, perhaps best left to the libraries. For rhododendrons only, the essential handbook is Sleumer's 1966 excerpt from Flora Malesiana , called An Account of Rhododendron in Malesia . Also he published supplements in the Dutch periodical Blumea between 1961 and 1973. All these are in English, but to help find your way, consult the reference people at a big university's library.

Beyond his academic and field career, perhaps a little bit said about Sleumer as a friend will help bring him into focus. When he visited Seattle in 1976, with an excellent program about tropical rhododendrons, he relaxed as our house guest and enjoyed trading tall tales about fun in the tropics. Then when we visited the Sleumers in 1985, we'd been badly delayed in producing a paper on Japanese rhododendrons, since some people had tried to transfer an azalea's name to a non-azalea. However, Sleumer got this straightened out with both the persons involved and the International Committee for Botanical Nomenclature, and we sailed ahead. Even more important, he handed us the original 1829 type specimen of the plant then called R. metternichii and urged us to look at, feel, and turn over this little piece of dried plant until we could accurately interpret and discuss it.