The Rhododendron, Camellia and Magnolia Group of the Royal Horticultural Society is supporting a Ph.D. studentship at the Royal Botanic Garden Edinburgh. This is in response to the urgent need to ensure continued expertise in rhododendron taxonomy following the retirement of Drs. David Chamberlain and George Argent. Tobias's first report follows

Report on Rhododendron Fieldwork in China
25th of August - 24th of September 2007
By Tobias Marczewski

As part of the PhD project on hybrid zones in Rhododendron, funded by the RHS, a collection trip to south west China was undertaken. The main aim was to obtain silica dried leaf material from Rhododendron populations of subsection Taliensia containing individuals of uncertain taxonomic status and/or obvious hybrids. During the planning phase Dr. Gao Lianming from the Kunming Institute of Botany (KIB) was of great help and everything from the arrival in Kunming on went unexpectedly well. We (Dr. David Chamberlain, Dr. Richard Milne and myself) were joined by Liu Jie a masters student at KIB, who acted as interpreter, and Yang Song, a professional and experienced driver from KIB.

After using the first few days in Kunming to set up everything for the fieldwork and inspecting relevant herbarium specimen, we headed of to Lao Jun Shan Hotel, situated at an altitude of 3800m, where we had scheduled a longer stay to acclimatize to the altitude. This site was chosen by Dr. Chamberlain based on observations of hybrids made during previous field trips to that area. One downside of the chosen season was that the Rhododendrons would not be in flower, leaving us with one character less for the identification of hybrids. But having a specialist like Dr. Chamberlain with on board this was a minor problem and considering the possible gain of the opportunity to collect seeds this was a reasonable decision.

The site at Lao Jun Shan offered much more than we expected and we were able to collect samples from various species representing different problems regarding hybridization and speciation. We sampled one whole ecological plot of 20 by 20 meters in a grid like fashion, representing a seedling recruitment area in a Rhododendron forest, composed of R. beesianum, R. traillianum, hybrids of the former two, and a few R. roxieanum individuals.
On other sites around Lao Jun Shan population samples were obtained involving R. clementinae, R. roxieanum, R. traillianum and, according to our field observations of special interest, R. roxieanum var. cucullatum.

Very much to our disappointment the weather conditions during the flowering season had been very bad and hardly any plants had managed to set seed, limiting us to a hand full of seedpods we were able to find.

Having completed the work on Lao Jun Shan after one week, we spent further six days in Yunnan Province collecting mainly different population samples of R. phaeochrysum and R. aganniphum including the taxonomically equivocal R. aganniphum var. flavorufum. Thereafter, crossing to southern Sichuan Province, we acquired further populations of R. phaeochrysum so that the collection of this species now covers a wide sample of populations throughout the distribution
range.

Due to time problems we were not able to collect desired allopatric reference populations of some of the species from Lao Jun Shan but overall the collected material is more than sufficient for the intended work to follow.

Summarizing the fieldwork was a complete success in terms of collecting the desired plant material and furthermore yielded most valuable observations regarding the population structure and hybridization behavior of Rhododendrons.