A Summary of Dr. Rock's 1948 Expedition to the Yunnan-Tibet Border
P. H. Brydon
Fig.1. R. fortunei series at 11,000 ft.
collected by the Dr. Rock expedition.
We are indebted to China for countless treasures which now enrich our gardens. That vast storehouse of horticultural material which gave us the progenitors of such important genera as Rhododendron, Camellia, Magnolia, Liliua, Rosa, Primula, and many more, is still a fertile land for the plant collector willing to risk his life in order that we may enjoy the fruits of his labors. The American Rhododendron Society was indeed fortunate to have the privilege of supporting Dr. Joseph Rock, one of the few remaining great plant explorers, in his recent expedition to the Yunnan Tibet frontier. Dr. Rock was very generous in his supply of seed and certainly is to be highly commended for his courage in tackling this undertaking in the face of unsettled conditions, not to mention the hardships which must accompany such a task, even in "normal times" if such a state ever existed in the wilds of that vast and turbulent country. The area which he traversed lies in the South Western part of China anti borders the Province of Yunnan where it meets the northerly limits of Burma and the eastern portion of Tibet. It is in this region where the two great rivers, the Salween and the Irrawady commence their southerly journeys of over one thousand miles to the Bay of Bengal. Mountains exceeding 15,000 ft. in altitude are divided by deep chasms and drenched by torrential rains. The forested slopes and mountain meadows are rich in Rhododendrons and the list of species collected is ample evidence of a job well done. Dwarfs of the Sanguineum Sub Series a few inches in height, to forest giants of the Falconeri and Grande Series (Fig. 9) up to 30 and 10 feet tall reflect the striking change in climatic conditions which exist in the territory covered by Dr. Rock and his native collectors. Upon their arrival in the spring, their first task was to prepare dried plant specimens for subsequent identification. Pertinent information as flower color, height, and habit of the plant, and altitude was noted. The dried specimen and the plant were given identical numbers so that in the autumn when the collectors returned to harvest the seed, they would be assured of collecting fruits from the same plant as was described on the herbarium sheet.
In the spring of 1949, the results of Dr. Rock's harvest was received by Mr. George Grace. Fortunately, Mr. Grace was about to depart for the Rhododendron Conference which was held in Great Britain this spring and he graciously consented to deliver the dried plant specimens to the Royal Botanic Garden at Edinburgh where they were identified by skilled staff of botanists. It will be noted in several instances that only the Series name is given. This may have been due to the fact that the specimens were not sufficiently complete, or perhaps damaged so that accurate identification was not possible. In some instances the abbreviation aff. (affinity) appears after the species name, indicating that the specimen, while resembling the type in a general sense, deviated sufficiently to question the use of the name without some modification. Two new species were discovered. numbers 53 and 54, which have been placed in the Sanguineum subseries. In due time, these will be given a name by the proper authorities, but in the interim, named or un-named, we will watch their development with a great deal of interest.
From a strictly ornamental standpoint, this collection contains many worthwhile species. It is unfortunate that the species are still in the minority so far as our garden material is concerned. To the writers knowledge, over 200 species have been propagated on the west coast, but a very small percentage has found its way into our gardens. This is due in part to the absence of a comprehensive collection where they might be seen and evaluated as ornamentals. It is gratifying to note that the University of Washington Arboretum, under the able direction of Mr. Brian Mulligan, is doing a splendid job of establishing an excellent planting of rhododendron species and it is our hope that before long we will see many of the finer types more generally used in our home gardens. Apart from their botanical and geographical interest, the species provide a pleasing contrast of foliage patterns and texture which is not to be found in the more pretentious hybrids.
Fig. 2. Seedlings grown from the
1948 Dr. Rock expedition.
Fig. 3. Seedlings grown from the
Rock expedition showing the variation
of habit and foliage.
The accompanying illustrations show a selection of twelve numbers taken at random from seedlings which were grown at Brooks by Mr. Aloys Winnekamp. Fig. 2, beginning from left to right, shows the following No. 1928: pennivenium aff.; No. 135: R. bullatum; No. 10: R. floccigerum; No. 188: R. lapponicum series; No. 73: R. niphargum; No. 181: R. triflorum series. Also reading from left to right, Fig. 3 shows No. 1130: R. heliolepis series; No. 33: R. eclecteum; No. 1838: oleifolium; No. 1938: falconeri series; No. 31: R. maddenii series; No. 179: R. triflorum series. The seed was sown in April of this year, germination was excellent and the seedlings are already showing their various character. To the plantsman, here is the ultimate in enjoyment. Watching each growth unfold, observing the first signs of indumentum, and recognizing the morphological distinctions between the various Series. By next spring, the new growth will begin to show the adult leaf structure, and two years hence an occasional flower bud will be formed. It is hoped that at least a few specimens of each species collected will be preserved, so that it might form a nucleus for the trial garden which one day will be established in the Portland area.