Letter to the Editor
I read with interest the article by Dr. J. P. Evans in the Bulletin Vol. 29 October 1975, No. 4, entitled 'Dr. Sleumer', describing a seedling of a Vireya rhododendron raised at Strybing Arboretum from seed of a cross made by me between the hybrid 'Dr. Herman Sleumer' and a form of R. zoelleri from West Irian. The picture on the color pages appears to be this cross and not 'Dr. Herman Sleumer' as so titled.
The rhododendron that I registered as 'Dr. Herman Sleumer' is indeed a natural hybrid but was not given to me as a cutting by Dr. Sleumer as suggested by the article but appeared amongst seedlings raised from seed of R. phaeopeplum sent by Dr. Sleumer from the Arfak mountain region of West Irian. It was the only obvious hybrid amongst some 100 seedlings, and in a letter from Dr. Sleumer after this seedling flowered, granting me permission to use his name, he mentioned that, at Boskoop, Holland, several seedlings of hybrid origin had also appeared amongst seed of R. phaeopeplum he had sent back there. After they flowered he considered them natural hybrids with R. zoelleri.
R. 'Dr. Herman Sleumer' has tubular-funnel form corollas, creamy yellow in the tube with deep pink lobes, much like the shape of R. phaeopeplum and a carnation-like perfume. The foliage is intermediate between the two parents, the new growth greyish, not brown. Rather interesting is the number of corolla lobes, 5, 6 and even 7 lobed flowers can occur on the one truss; this has been observed on all crosses that have been made here between the 7 lobed Phaeovireya species R. leucogigas, konori and phaeopeplum and species of Subsection Euvireya Series Javanica (5 lobes). One particular seedling of a cross between R. lochiae and R. leucogigas produced one truss of 9 flowers all of which were 7 lobed. In other respects all seedlings were intermediate between the two parents.
R. 'Dr. Herman Sleumer' has proved an excellent parent so far with the crosses that have already flowered. The original back cross with the West Irian form of R. zoelleri which was the subject of Dr. Evans article has been repeated using a form of R. zoelleri from the Mt. Hagen area with larger and richer colored flowers. Up to the present time, seedlings of 48 different crosses have flowered here, some of them being quite remarkable rhododendrons.
I agree with Dr. J. P. Evans in his assessment of the future of Vireya rhododendrons, particularly with Peter Sullivan carrying on the good work at Strybing Arboretum.