On Friday John and George explored a corner of Seabranch State Park near Port Salerno, Florida, previously unpenetrated by us, a big area of scrub more mature with larger Oaks and Pines than many other local scrub areas.
The Prairie Clover (Dalea feayi) was pleasingly in bloom.
The Yellow Garden Spider was enjoying the day.
If we’re going to feature Chapman’s Oak, we better establish who was Chapman? Alvin Wentworth Chapman (1809-1899) witnessed most of the 19th Century, remaining active to age 90. He was a physician and founder of modern Florida botany. Back then doctoring and botany often occupied the same soul. (Come to think of it, my own father was a physician-and part-time naturalist.)
I believe many species distinctions we use in modern manuals date back to Dr. Chapman’s antebellum (1860) Flora of the Southern United States, setting up subsequent generations of addition and refinement in 20th Century floras. Originally from Massachusetts and a Union sympathizer in the Civil War, Chapman lived most of his long productive life isolated in Apalachicola.
Most local scrub areas host Chapman’s Oak, and in Seabranch State Park this species is abundant, in fruit, big by local standards, and striking with two special eye-catching features:
Feature #1: Galls as big as ping pong balls and as red as apples, before turning brown.
Eye-catcher #2: Super-glossy-reflective leaves. Chapman’s Oak has some of the larger leaf blades found in the sun-drenched scrub habitat where the general tendency in most plants is toward reduced leaf sizes. You’d think those big Chapman solar panels might cook and dehydrate in the scrubby sunbath, and we’ll see in a moment that to be the case in a limited way, but I’d like to think that reflective surface offers protection. We usually think of big leaf blades as typical of shade, so maybe Chapman’s Oak straddles the best of both worlds: expansive blades for life in a mature scrub under the shade of Pines, and at the same time protected when un-shaded. This is mere speculation—the prerogative of the individual who types the blog.
Several species of Oaks grace our local scrubs, and they are an interesting committee. We won’t sort out here how to tell them apart (for help see Lesson 3 in our online class), but some general remarks may interest a reader or two.
Would you expect a cluster of Oak species living in the same habitat in the same place to be closely related? They are mostly just the opposite—a highly disparate group all thrust together. Think of a bunch of new neighbors getting acquainted around the pool in a recently built Florida condo complex (perhaps built where scrub once was). The first conversation topic over frosty Coronas at the meet & greet is, “where are you from?” —- “We’re from Syracuse,” “I came here from Philadelphia,” “Minneapolis,” “Argentina,” etc. Same thing with the Florida scrub-dwelling Oaks. They all came to Seabranch State Park from different directions, different relationships, different histories. How’d they all get together in the same scrubby sandbox? Fairly remarkable, so Floridian, and just like human Floridian transplants, they have their own subtle climate preferences, especially with respect to differences in soil water on that scrubby sugar sand. We’ll return to that.
You can divide the local Oaks into three distinct species alliances, the Red Oaks, the White Oaks, and the Live Oaks.
Representing the Live Oak species group, in Seabranch, we met Sand Live Oak (Quercus geminata) and Dwarf Live Oak (Q. minima). From the Red Oak Guild was pretty Myrtle Oak (Q. myrtifolia). Chapman’s Oak alone hails from the White Oak gang.
Today it is all about Chapman’s Oak. Wonder why it is so rare in cultivation? Apart from any necessary symbiotic microbial partners, its soil moisture preference is under 7%! (Sand Live Oak, by comparison which is cultivated prefers over 12%.) Chapman’s Oak, perhaps by dint of longevity, can extract water from fairly deep scrub soil, recorded down to over 6 feet. It initiates leaves during the early rains of Spring, having them in place during the long hot summer and early autumn. As the dry season rolls around, Chapman’s Oak is particularly prone to have those oversized leaves dehydrate internally…drier than any of several scrub species measured. Remember our worries above how big leaves may dry out. They seem to, to a point, but under protected control, on schedule, and basically okay. Mother N watches over her Oaks.
Chapman’s nearest relative, as revealed by DNA, is the so-called Bastard White Oak (Q. austrina). BWO inhabits more-northern Florida and beyond on soil with more moisture. In short, you might interpret Chapman’s Oak as a heat-seekin’ dry-lovin’ derivative of its bastard northern cousin.
Note: Technical data largely from article by J. Cavender-Bares and collaborators. Phylogenetic Overdispersion in Floridian Oak Communities. Am. Naturalist 163: 823-843. 2004.