Serviceberry: preaching the gospel across the Appalachian Mountains

Serviceberry roared into flower this week, going from bud to bloom in a few hours, or so it seemed. From a distance these small trees present puffs of bright white in the dusky woods. Seen close, the flowers are indecently large and gaudy: this is no subtle, ground-hugging anemone flower. The serviceberry is famous all over eastern North America for announcing spring with a vigorous fanfare, usually at the head of the line, weeks before other trees and shrubs shake off their winter torpor.

The species goes by many names, surely more names than any other understory tree. Here are the names that I’m aware of, no doubt I missed a few: serviceberry, sarvis, sarvisberry, shadbush, shadblow, juneberry, sugarplum, wild plum, Indian plum.

Etymology is clear for some of these names, but not for others. “Shad” refers to the shad fish (genus Alosa) of the northeast whose return from the oceans to their upriver spawning grounds coincides with the bloom of the “shadbush.” “Plums” refer to the fruits which are consumed with gusto by birds and small mammals and, depending on the variety of tree, by humans.

“Sarvis” is a mountain dialect variant of “service,” but the origins of these terms is not clear. Some claim a corruption of Sorbus, the scientific name of a related plant, the mountain ash. Others associate the name with church services: the return of traveling preachers as winter roads became passable or the use of the blooms as decorations for Sunday worship. I learned of another interpretation from Jay Leutz’s book Stand Up That Mountain. In the higher parts of the Appalachians, where winter freezes are deep and long, the tree blooms as soon as the ground thaws. This time marks the first opportunity to dig graves and hold funeral services for those who have died in winter and whose bodies await burial. On the Cumberland Plateau, at least in the years I’ve lived here, the ground is fit for burying many weeks ahead of serviceberry blooms. Different meanings are heard in different landscapes; our understanding of language molds itself to place.

Serviceberry also offers us a curious parallel between nomenclature and biology. The genetics of this genus, Amelanchier, are particularly complicated. Dozens of forms exist. These forms hybridize, creating new variants and causing mental (and gastric) distress for any taxonomists who dream of order in the Natural Order. Some forms switch off sexual reproduction and set up small populations of asexual trees. These “microspecies” sometimes then switch back to sexual reproduction and interbreed again with other forms. In all, the genus is a hyperdiverse genetic tangle in which firm species do not exist.

This seems frustrating, but many biologists see the situation otherwise. Here, for example, is our friend Darwin in the second chapter of The Origin, discussing the serviceberry’s unruly relatives in the Rosaceae family:

I refer to those genera which have sometimes been called “protean” or “polymorphic,” in which the species present an inordinate amount of variation; and hardly two naturalists can agree which forms to rank as species and which as varieties…

Certainly no clear line of demarcation has as yet been drawn between species and sub-species…

Hence I believe a well-marked variety may be justly called an incipient species…

From these remarks it will be seen that I look at the term species, as one arbitrarily given for the sake of convenience to a set of individuals closely resembling each other, and that it does not essentially differ from the term variety, which is given to less distinct and more fluctuating forms.

For Darwin, these variable “species” and “varieties” were evidence for continuity in nature. Today’s species is yesterday’s variety. Life evolves; don’t expect tidiness.

We can only speculate what the traveling preachers of the 19th century might have thought of having their arrival heralded by an example of Darwinian mutability. I like to think that at least a few may have reached for the wild-plum wine.