In the Texas Hill Country there is a shrubby tree known locally (and incorrectly) as the "Texas Mountain Laurel." While the taxonomy of this small tree is not the topic of this post, suffice it to say that it is not a member of the Laurel family nor is it restricted to mountainous areas. It does favor predominantly calcareous soils, which the Hill Country, with its thick strata of limestone bedrock, provides in abundance.
For most of the year Sopophora texana is an attractive but otherwise unremarkable element of the native flora, its shiny, dark evergreen leaves being its most compelling feature. In late winter or early spring, however, it is one of the earliest-blooming native trees, a true harbinger of pleasant times. Its clusters of purple blossoms resemble those of the introduced Wisterias but are much darker.
A legume, the blossoms of the Texas Mountain Laurel result, weeks later, in a brownish-colored pod about 5-6 inches in length. Splitting open the pod reveals a number of the most surprisingly scarlet-colored beans, the so-called "mescal bean."
An alternate, less attractive, and equally erroneous name for this tree is the "Mescal Bean." Now as any devotee of Mexican fermented beverages will quickly note, true mescal is derived from the fermented hearts of several different varieties of agave known locally as magueys. The bean of the Mountain Laurel, however, contains several allegedly potent alkaloid compounds, which when taken orally can result in either a state of intoxication resembling overindulgence in mescal, or, in the worst case scenario, death.
Even in urban portions of San Antonio, which straddles the Balcones Fault (and thus is technically half on the Edwards Plateau), it is possible to find "Mountain Laurels." A favorite area of mine was Olmos and Contour Drives in the Olmos Park suburb, sinuous streets that are lined by great numbers of Mountain Laurels, many perhaps native some perhaps introduced.
The real charm of this plant, for me, has always lain in the olfactory arena. Where the trees are abundant, the flowers produce a sweet, cloying scent that is literally capable of filling a Hill Country canyon with its fragrance. The dreamy, sensuous euphoria this perfume could induce in me during long-ago springtime forays was almost atavistic. It is, or was, a fragrance that I associated with my wastrel youth. As likely as not this would involve ditching an afternoon lab class to wander through some Hill Country canyon, absorbing the natural wonders of the place and especially that fabulous, mysterious scent. Even years later, a faint whiff of "Mountain Laurel" blossoms could transport me back to that wondrous time of life.
It still does, to some extent, but much of the mystery has vanished. Several springs ago, Sara and I were walking back to the vehicle after having hiked the Sabinal River trail at Lost Maples State Park. We had just seen a beautiful male Golden-cheeked Warbler that must have arrived only a few days earlier. Passing through a grove of "Mountain Laurels" along the trail, I reached out and plucked one of the purple blossoms and inhaled deeply from it. Passing it to Sara, she did likewise, then commented, matter-of-factly, "Grape Soda."
"What?!" I said, as if she had uttered a non sequitur.
"Grape Soda," she repeated slowly, patiently. "Mountain Laurels smell like Grape Soda. You've never noticed?"
I hadn't! But suddenly, in the more analytical portion of my mind, it made sense. Esters! Of course! Even though I have spent most of my professional life as a high school chemistry teacher, having conducted laboratories that produced similar esters, I had failed to make the connection.
Esters are an engaging group of organic chemical compounds, many of which are responsible for the pleasant smells we encounter in everyday life (as well as a few not-so-pleasant). Sara's olfactory sense had instantly isolated the active ingredient in the long mysterious "Mountain Laurel" fragrance. Indeed, it could be this very ester, produced in the laboratory and added to sugar and the other ingredients that give grape flavoring to most powdered or soft drinks. When you see the words "artificial flavoring added" on a container, they're talking esters! Grape Soda, which contains nothing derived from actual grapes, manages to taste more grape-like than even real grapes (or so we've been programmed)!