The great whale-shaped mountain of granite, far from being the bare rock that it appears, is literally covered with plant life. Thirty specimens of plants are listed as rare, and many more are so uncommon or so regional as to be total strangers to nearly all visitors.
Botanists from Emory and Georgia State Universities in nearby Atlanta, and the University of Georgia in Athens, have regarded Stone Mountain as their special laboratory since the schools were founded. In 1961 a full-time horticulturist was employed to live on the mountain. Harold Cox, from Stratford, England, studied at the Royal Botanical Gardens at Kew. His assistant, Gerhard Oortman, grew up working in the magnificent gardens of Eastern Holland. They have become intimately acquainted with practically every weed, twig, bush and tree on Stone Mountain.
They have ascertained that the Hypericum is the only shrub that grows nowhere else. Hoping to have specimens where visitors could recognize them, without running the risk of having souvenir hunters exterminate the genus, Cox and Oortman rooted some cuttings in the greenhouse and set them out in a garden plot across from the carving—and saw them promptly wither and die. However, some seed planted in the same ground have sprouted and seem to be thriving.
Stone Mountain’s botanical treasures are governed partly by the seasons and partly by the amount of soil available. The most spectacular of the unusual plants is the Viguiera porteri. It is so rare that it had no common name until the Stone Mountain natives titled it Confederate Daisy. It has relatives in Mexico, but the American branch is confined entirely to Stone Mountain and other granite outcrops of Georgia’s Piedmont Plateau.
The Confederate Daisy grows in swales or crevices where sand or soil has collected to a depth of three or four inches to a foot. The plants would be regarded as skimpy little weeds throughout spring and summer. A dry summer stunts the year’s crop. But when frequent showers dampen the mountain’s surface, the scrawny plants put on a big spurt of growth in August. About the middle of September they burst into great beds of blooms, making the nearly bare rock look like a golden meadow. The profusion of color lasts until mid October.
In early spring the Diamorpha cymosa spread like a bright red carpet where soil is half to an inch deep. The color is in the plants, two or three inches tall, and in the succulent round leaves. Tiny white blossoms detract, rather than add, to the color.
The Amphianthus pusillus has no common name. It is a member of the snapdragon family, but is so small that it is rarely noticed except by naturalists who are looking for it. However, it leads a remarkable existence.
The Amphianthus lives in the rain pits on top of the mountain, small sunken areas where water collects after each shower. When the pit dries up, the only sign of the plant is a little cyst under the sand and gravel at the bottom. Immediately after a rain the cyst sends up a little rosette of reed-like leaves that stay submerged. From their midst a thread-like stem arises and sprouts two leaves half an inch across, that float on the surface. A tiny bud appears between the two leaves, and opens into a white flower no more than one-sixteenth of an inch across.
When the pool dries up, the plant disappears, quickly turning to dust, except for the cyst, which waits patiently for the next rain to bring it back to life.
The Amphianthus is not exclusive with Stone Mountain. It has been seen on Mount Rollaway in Rockdale County, but it is missing from some of the other granite outcrops. Cox called it a monotypic genus, which means it is represented by the one genus.