I was surprised to find that it was not on Skean’s plant list from the 1980s. In addition, John Connors, who was the first manager of Durant Nature Preserve and knows this place and its critters intimately, was also not aware of this species on the preserve. So I added it to the list, wondering what other treasures I might find here.
The next year I eagerly awaited the emergence of Turtlehead by the lake. That first year I could see it near the trail and by canoe, so I watched the shoreline both ways. No turtlehead emerged that year or the year after. I haven’t seen it since.
It seems strange that this plant would just appear and then disappear again so quickly. Here one year, gone the next? No evidence suggests that it was planted by anyone; it may well have established on its own. Perhaps it could have been there for a few years, but it seems like it was not there for long. It was not in an obscure, difficult-to-access location, so it seems like people would have noticed it. On canoe programs, I’ve met at least one other person who saw it, during that same year. Perhaps it goes dormant, staying underground for a few years and reemerging when conditions are right. This seems unlikely, as I have not found any information on dormancy in this species.
So why did it disappear? Maybe seeds established briefly in a less-than-ideal habitat, yet still good enough for plants to flower. Or it could be because small populations are at a disadvantage. Small populations are more likely to be decimated by random events, just because there are so few in the population. Or there could be too few in the population to establish in the first place (not enough mates, or not enough genetic diversity, etc.). Many small populations may disappear before we even notice they are there.
On the island of natural habitat preserved here, populations of many species are small, experiencing the disadvantages described above. Several other plant species have disappeared from the preserve (local extinction). These plants may have been rare all along, or may have been common but local to one small area, dwindling down to nothing over years. After three years of searching, I have found 389 of the 487 plants on the original list by Skean. I still hold out hope of finding some of the 98 plant species I have yet to document from the original list, but several of those plants are likely to be extinct here. As land use changes in and around the preserve, as climate changes, and as more people access the land, some plants and other species wink out of existence on the preserve, and some new living things find their way here (or were here, undetected, all along). So far, I have found 215 other plant species not on the original list—about 140 of these are native to this area. I mourn species losses but am excited whenever a “new” native plant shows up, or when I find a plant on the list that has eluded me.
But Turtlehead is a strange case. I am glad I intersected with it, and I hope it returns one day
References:
https://www.inaturalist.org/observations/185238443
Skean, J.D. 1982. The vascular flora and plant community types of Durant Nature Park, Wake County, North Carolina. M.S. thesis, North Carolina State University. Raleigh, North Carolina.
Bitternut Hickory (Carya cordiformis) at Horseshoe Farm Nature Preserve
I had found many of the “expected” hickory-associated leaf-mining species on Bitternut Hickories at Horseshoe Farm before, but in late May I found one I had never seen on any hickory before: a tent miner in the genus Phyllonorycter.
“Tent miners” are leaf-miners are like other leaf-mining moths in that they feed in between the upper and lower layers of the leaf, in the tiny, thin space in between. Tent miner caterpillars make a space for themselves by hollowing out a small area within the leaf, then spinning silk over the lower part of their inner chamber. As the silk dries, it shrinks, pulling the lower layer of the leaf together, and causing the upper layer to buckle upward into a tentlike structure (see the photos below). Then the caterpillar feeds on the leaf inside the chamber, until it is ready to pupate. Several genera of moths in the family Gracillariidae make mines like this. Caterpillars in different genera have different behaviors. In some cases, caterpillars exit the mines and feed in rolled leaves before pupating. In others, they exit and make cocoons externally without feeding outside the mines. In the genus Phyllonorycter and a few other genera, caterpillars pupate inside their leaf mine. Their pupa then pops out of the mine, allowing the adults to pull out of the pupa case and fly away to mate and lay eggs.
Lower side of the Phyllonorycter leaf mine on Bitternut Hickory
Upper side of the Phyllonorycter leaf mine on Bitternut Hickory
In this case, I collected the leaf with the tent mine on May 26, and an adult emerged on June 11. The adult is a bit of a mystery. Apparently, the two Phyllonorycter species known to eat hickories as caterpillars look very similar. One is known to eat Bitternut Hickories, but has not been found in North Carolina yet. The other has been found three times in North Carolina (in two counties) but is not known to use Bitternut Hickory as a host. Male anatomy or DNA can help distinguish between the species. Since my specimen is a female, I’ll need to wait until DNA analysis can be done to figure out which species this is.
Meandering can sometimes reveal mysteries. At least this mystery is solvable, with time and the right expertise… But before that happens, a good bit more water will flow past the horseshoe bend…
References: https://www.inaturalist.org/observations/365791326