The story begins with Eugene Allen Smith, longtime state geologist. During
his summer field trips to document and describe Alabama's geological features, Smith also collected plants of interest. In July 1877, he clipped a branch from an odd-looking shrub growing on the limestone bluffs at Pratt's Ferry near Centreville; he later passed the specimen on to Charles Mohr, a Mobile pharmacist and botanist. Mohr was likewise puzzled and sent the specimen to the reigning authority on Southern plants, Alvan Wentworth Chapman of Apalachicola, who formally named the plant in the second edition of his Flora of the Southern States. Thus it was through the combined efforts of Smith, Mohr, and Chapman that Croton alabamensis came to scientific light.
Alabama cratons are uniquely adapted to their harsh rock outcrop environments, surviving (and even thriving) where few plants can. The shallow mat of broadly spreading roots assures that every molecule of the limited available moisture will be tapped. The shimmering leaf scales reflect the sun's rays, cutting down on heat stress and water loss from leaf surfaces. With rapid flower development in the spring, followed closely by fruiting, seed maturity, and seed dormancy, these high-cost reproductive events are accomplished long before the summer drought. By early summer, in fact, many leaves become completely dormant, shutting off their photosynthesis, and turning yellow or bright orange before falling to the ground.
While the croton is so highly adapted to the heat and drought of its habitats, a major question remains: How did it get to these isolated pockets in the first place? The working hypothesis, initially formulated by Mohr, is that its current distribution is relictual--a holdover from a previous era. Species like the croton once enjoyed a more widespread distribution, but, during the shifts imposed by the Wisconsin glaciation, were pushed south into protected ravines and river bluffs. Following the retreat of the glaciers, other species returned north, but the croton remained confined to its tiny, rock-strewn pockets, protected from the frequent fires that swept the surrounding pinelands. Mohr put it best:
If we regard these plants as the slightly modified descendants of types belonging to an ancient flora, which have survived the changes our globe has undergone and have found a refuge in their present localities, the mystery of their strange isolation finds a satisfactory solution.
The Alabama croton, then, is a botanical survivor, pushed into seemingly inhospitable places by forces no longer at work. And it remains there, in protected isolation, hanging on by its shallow (but ever-so-efficient) roots.