I have been noticing a lot of Jack-in-the-Pulpit plants with five leaflets per leaf instead of the usual three. I also notice that there is a species for this, Arisaemia quinatum. One of my field guides says it is “often considered to be a variety of, or not distinct from, A. triphylllum.” The plants I am seeing are definitely not Green Dragon (A. dracontium). They are usually growing in the same area as the three-leaflet Jacks. I have even found plants with one three-leaflet leaf, and one five-leaflet, or even with a four-leaflet leaf.
I am curious if anyone has done any research on this. If you look at my observations, you will probably conclude that I am obsessed with this, because I post so many pictures of it!
More recently it has been accepted as a separate species. I recently became interested in these 3 species (2 jacks & dragon). I’ll talk more about it later. I’m too busy today through Saturday to get into it.
Beware- Arisaema quinatum is indeed a separate species, but has a limited distribution restricted to the southeast. Even in that region, not all jack-in-the-pulpits appearing to have five leaflets will be Arisaema quinatum: individuals of Arisaema triphyllum proper will also occasionally show 5 leaflets (or more often just one of the lateral leaves will be divided, so there’ll appear to be a fourth smaller leaf), something I often see further north where quinatum does not occur, though they’re usually not as dramatic as in quinatum. Arisaema triphyllum is being split further based on other characteristics than just the leaflet morphology, with Arisaema stewardsonii and pusillum being relevant where I live in the northeast, and acuminata occurring in the southeast. Aside from the leaflet morphology, A. quinatum is also distinguished from strict A. triphyllum by its narrower, often curved spadix and hood morphology.
I’m curious about this as well. I, too, noticed a lot of “five-leaved jacks” on my walks and saw there was a separate species so started calling some of my observations Arisaema quinatum. After some more reading then I wasn’t convinced that’s really what I saw and believe they may just have been five-leaved Arisaema triphyllum based on hood color and striping. With the recent splits in this genus, I’m not sure yet how to tell them all apart and pretty sure I probably have misidentified some of mine as well as for others before I realized there had been a split. Sounds like a genus that could use some clean-up.