John and George botani-snooped Halpatioke Park in Stuart today, always a source of photogenic plant diversity. Unlike previous weeks, the park was awash in the odd little annual grass Steinchisma laxa, which seems to have popped up in response to some cue. The other domineering presence, Goldenrods (Solidago species), take their cue from lengthening nights after the summer solstice. There exist about a hundred species, mostly in North America. Pinebarren Goldenrod, Solidago fistulosa, was the main showoff here and now.
What does everyone know about Goldenrods? Allergies, although it is probably a bum rap. The big sticky insect-borne pollen grains are not likely to wind up often in your snoot if you don’t sniff bugs, although flower arrangers know Goldenrods to irritate the skin
Bees are the main pollinators, and additional insects visit. Today Soldier Beetles resembling lightning bugs without the flashlights were on duty. Often associated with Goldenrod, they lurk among the blossoms catching other insects, mating, and eating those pollen grains.
The name Solidago means “becoming whole,” as in healing. There are too many medicinal applications to list, and most are boring. However, there’s probably validity to some of the historical uses. The plants are bioactive, including a handy ability to suppress soil pathogens (and human pathogens?) via root exudates. And Goldenrods produce natural pre-emergent herbicides to throttle germination of competing seeds, at least in the lab. Some folks like Goldenrod Tea, but why blithely consume any bioactive plant? I’ll stick with Winn Dixie tea. Goldenrods have touched automotive history too:
Thomas Edison, Harvey Firestone, and Henry Ford shared an endeavor in the early 20th Century. Around WWI time they fretted about rubber running low. Ford tried Rubber Tree (Hevea brasiliensis in the Euphorb Family) plantations in the Amazon. Firestone went for Liberia. Double failure, yet cars were proliferating nationwide like Goldenrods sprouting across the meadow. The Captains of Industry realized that many plants other than the proper (Para) Rubber Tree make latex, including Ficus elastica and the Palay Rubbervine. The former graces waiting rooms nationwide. The latter is a showy weed in hot-climate America from its introduction as an attempted rubber plant. Most importantly for today, also giving up latex are many species of the Aster Family, including the much-touted Guayule, Dandelions, and Goldenrods. You can farm these.
And now comes a big Florida connection. Brainstorming Goldenrods took place at Edison’s Ft. Meyers compound along with Florida-oriented botanist John Kunkel Small and University of Miami botanist Walter M. Buswell. Interesting how the elite of that era got together. Even distant Luther Burbank had a hand in the doings.
Edison had found 2000 ways not to make a light bulb. That was just a warm-up for selecting a plant to cultivate for latex. Edison (a tired assistant) ground through 17,000 dud species, until Solidago leavenworthii emerged with 12% latex content. This species ranges throughout Florida. The Solidago rubber worked; prototype tires were made and driven. So Edison thought he had it nailed by the late 1920s, and Goldenrod Rubber went forth with fanfare. Altogether not too shabby, but too little too late, as synthetic rubber nudged all 17,0001 species aside. Gasoline did the same to the electric car battery under development at roughly the same time.
A hundred years later, the electric car battery and bio-based rubber have bounced back. Several corporations are developing tires and other rubber products based on biomass, plant-oils, “waste” animal fats, and sugars with the help of bacterial enzymes. Reliving Edison’s brief triumph a century ago modern engineers have made prototype green tires, which may be on your electric car by 2015.
Goldenrod’s cousin Dandelion (especially a Russian species) has come into contention as an industrial rubber source for its milky latex, just as in Goldenrod. CLICK and CLICK AGAIN Remarkably, the process involves genetically engineered viruses if you can get your mind around those. If Dandelions work it would be no huge stretch for related and similar Goldenrod to resurface too, so Goldenrod tires are still conceivable.
Let’s exit Tomorrowland and finish up back in Halpatioke. We saw more galls on plants today than perhaps any other time or any other place. This seems to be the summer of the galls, at least in Stuart. Most were on oaks, but Goldenrods are gall favorites too. A study around Gainesville showed 122 species of insects to attack Goldenrods in some capacity or another. The best-known Goldenrod gall-makers are gall flies of the genus Eurosta. Long ago and far away I used to enjoy cross country skiing in Michigan. At that time the Goldenrod galls on dead stems above the snow were sufficiently conspicuous and odd to be memorable now. The fly larvae lodged in the galls persist long after stalk death to emerge the following spring—after bitter cold and/or life-sucking dryness, depending on the locale. Noting this, biologists have studied the larvae as examples of bizarre adaptation to extreme conditions. How can a little worm in a pod get through 10 degrees below zero or months of desiccation and pop forth smiling?
[Special thanks to my tire-expert engineer son Martin for a heads-up on new bio-tires, especially the Russian Dandelion.]