 | |  |
THE NORTHWARD RETURN
With good collections of R. serrulatum one could feel with fair satisfaction that the gamut of southern azaleas had been about run, until such time as return visits to puzzle areas might be called for in another year. A northward return was thus in order, so planned as to catch any further outliers of the R. serrulatum complex together with a fairly detailed survey of its northern counterpart, R. viscosum, which should now be in scattered bloom well into New England.
Leaving Folkston on the 28th of July, our route headed towards Savannah and the Georgia side of the Savannah River where late azaleas had been observed during the R. speciosum season. The only collections this day were of fine specimens from a northerly distribution of Befaria racemosa, the curious ericaceous Tar Flower which, with its spikes of pink blossoms, is suggestive of a primitive azalea form. Here in coastal Georgia it grows on dry soils of the Pine-palmetto forest. Farther south the scattered clumps of this single North American representative of a Central and South American genus is a frequent sight along the Florida roadsides.
Occasional Hammocksweet Azaleas were seen on the way to Savannah while, bypassing this city, the first low white azaleas resembling R. viscosum rather than R. serrulatum were found at a woodland edge in Effingham County. Farther along, in Screven County, there was found a swamp near Oliver where the swamp tussocks were covered with quite normal R. serrulatum, the swamp margins with a very variable dwarf and stoloniferous azalea, sometimes highly pubescent in its buds and leaves which was clearly much more akin to R. viscosum than the other species. On drier land an outer circle of R. canescens, past bloom, completed the azalea picture. This was the last collection of R. serrulatum, which does not seem to spread north of the Savannah River. It is clearly a region where the two late white azaleas meet and as such it is likely that gene exchange with resultant variability could be expected here in East Central Georgia.
Crossing the Savannah River on Route U.S. 301, this road was followed north to Baltimore, as it parallels the coast some 100 miles inland. Throughout the distance of the Carolinas, Virginia and Maryland, R. viscosum was mass-collected, usually in good bloom, at intervals of approximately 60 miles. From Baltimore it was followed past Philadelphia into New Jersey, across New Jersey to Connecticut, and across Connecticut and Massachusetts to Cape Cod and even to the island of Martha's Vineyard where it was flowering on August 8th. This was another thousand mile run in which the variation of one species could be observed, step by step, until it became a fascination that terminated only as the last plants were collected. From the dwarf, twiggy and semi-evergreen bushes of the marshes of South Carolina to the tall, gray leaved and large flowered shrubs of the pond margins of Cape Cod, the Swamp Azalea is much more changeable than its sister of the Gulf Coast. Rehder has divided it into eight varieties and forms. One could make these many more, or less, depending upon the, viewpoint of the observer. It seems certain that not a little of the trouble is due to R. viscosum and arborescens having met on occasion in the northern states, as was strongly suggested by the last New York State and Pennsylvania collections on the return to Philadelphia. In some of these northern swamps genes have been so freely exchanged between these two species that nomenclatural assignment of present populations becomes virtually impossible. The situation is similar to that previously noted with regard to R. roseum and nudiflorum. But in spite of these local happenings, R. viscosum can still be regarded as “good” a species, though variable, as R. roseum, nudiflorum or serrulatum.
This last run from central Pennsylvania to Philadelphia was on Sunday, August the 12th, and thus ended, after 21 weeks and 25,000 miles of almost continuous collecting, our quest for native azaleas. A few additional collections have since been made, as doubtless there will be others in the future. From this major field survey were secured 8,000 herbarium specimens and 500 living plants whose study should throw much new light upon the nature and the behavior of these plants. The herbarium specimens, now mounted and catalogued, are deposited in the herbarium of the Morris Arboretum of the University of Pennsylvania, at which institution the collection of living plants is also maintained for future observation and for their use in current cytological studies.[*]
| | |