The first bloom of tender spring ephemerals is winding down, but on brushy hillsides where few other wildflowers grow, one tough little plant is coming into its own.
Jack-in-the-pulpit, Arisaema triphyllum, first emerges from its corm as a fleshy sheath enfolding the baby leaves…
…which soon push skyward and begin to unfold.
Though Jack-in-the-pulpit is relatively abundant in some parts of this forest, the density of the population on this particular hillside is surprising. It’s been about eight years since the large, heavily shading Bush honeysuckles that dominated this site were removed; since then the small light-starved Jacks have rebounded and spread happily .
I spent an entire afternoon, mostly on hands and knees and sometimes prone, to collect these images.
It was like a treasure hunt – finding one Jack after another after another, each with it’s own unique personality.
Jack is part of an ancient lineage; the Araceae or Arum family is one of the oldest angiosperm families, with fossil records from the late Cretaceous. Perhaps this accounts for its unique reproductive structures, consisting of a protective spathe sheltering a clublike spadix.
I’ve found no explanation other than “genetic variation” for why some Jacks are all green. The flowers are not trying to attract bees or butterflies so bright colors likely don’t matter.
Instead, Jack’s mushroom-like odor attracts tiny insects, particularly fungus gnats. Since the inside of the spathe is slippery and steep, male flowers have a tiny exit hole near the base of the spathe. Female flowers however, don’t allow gnats to escape, helping ensure pollination. I have to wonder if carnivorous plants might have evolved in this fashion.
Something (not me) has removed the spathe from this female flower, revealing its floral anatomy. The actual flowers surround the lower part of the spadix. The presence of two leaves on this plant indicate it’s a female – this year anyway. Jack may also be Jill, since this species is a “sequential hermaphrodite”, able to modify or switch gender in response to the age of the plant and amount of stored energy. Female plants need more stored energy to ripen seeds, but may switch back to mostly male flowers the following season.
Most of the plants on this hillside are female, so they must be thriving. Increased sunlight is likely a factor, due to invasive plant removal and the loss of large ash trees to the Emerald ash borer. Though there is increased competition in the herbaceous layer, Jack seems deal with it just fine. I have found big healthy plants deep in brushy thickets of blackberries.
It will be interesting to see how successful their reproductive efforts are, based on the number of berry laden stems later this summer. Though deer do bite off some of the flowers, hopefully they will not develop a preference for them.