I sometimes receive e-mails from readers intrigued by the oddities of the plant world. Since I love telling you about the wonders of nature, even if it’s not directly related to gardening, I wanted to share with you a discovery made by a reader…
A discovery that prompted me to do some research, and the information I found literally fascinated me!
A Curious Plant
The reader in question sent me these photos of a Jack-in-the-pulpit specimen so colossal it could be used as an umbrella by a troll…
This immediately piqued my curiosity and prompted me to embark on further research. I may be a biologist, but I don’t know everything, and I’m certainly not an expert on troll umbrellas. The Jack-in-the-pulpit, a small undergrowth plant, is an araceae. Ever heard of the peace lily? Well, they’re in the same family. Can you see the resemblance?
In fact, when you’re lucky enough to see a Jack-in-the-pulpit (I say lucky, because it’s a rather discreet species, and it’s very easy to pass it by without spotting it), you’re bound to be puzzled. Is it a flower? A carnivorous plant?
In fact, the strange organ that forms the calyx is the spathe. It’s a transformed leaf, just like the Peace Lily. Jack-in-the-pulpit flowers are tiny and are all on the small spike in the center (the spadix), which is protected by the spathe.
Now that this enigmatic plant is (slightly) less strange to us with its three-lobed leaves and spathe streaked with dark red and white, let’s move on to what makes it truly intriguing: its mode of reproduction.
“OK, but where’s the giant umbrella?”
The Arisema and Its Extraordinary Sex Life
I’m not telling you anything new if I say that flowers are often visited by pollinators to spread the pollen all over the other flowers. But, unlike the classic flowers that attract bees and butterflies, the Jack-in-the-pulpit has developed a surprising relationship with blighters, tiny stinging insects.
Also known as “$?&*? flies” (I salute people living in the boreal forest!), these insects feed on blood by stinging. Since they cause an immediate burn, they’re also known as “burns”. Having spent two weeks in the field in the Laurentians in June during my studies, I personally have a deep-seated hatred for this pesky fly, but that’s not today’s topic…
In short, these blossoms visit the blossoms of the Jack-in-the-pulpit, distributing their pollen. The strange thing is that, as you’ll recall, the blighters feed on the blood of biology students… They’re not strictly speaking “pollinators”. So why are they attracted to this flower and what do they find interesting?
A mystery! Even scientists haven’t found the answer.
Male, Female, Both, Neither? Go Figure!
With its underground rhizomes, Jack-in-the-pulpit has the ability to regrow every year. There’s even speculation that the plant can live for hundreds of years, regenerating from the same rhizome. It’s an easy, low-maintenance plant, making it a great curiosity to have in your flower beds.
Especially if it’s the size of an umbrella… for just one year! (It’s coming, we’re getting closer to an explanation).
This plant is dioecious, which means that an individual has either male or female flowers, but not both. This isn’t so strange; many plants have a well-established sex in this way. But in the case of this arisema, things aren’t quite so simple…
Each individual plant is free to “decide” each year whether to make male or female reproductive organs. This is called sequential hermaphroditism.
How Is This Possible?
The rhizome has the genetic baggage to produce either a male or a female. If its reserves from the previous year are high enough to produce fruit, the rhizome will produce female flowers. If, on the other hand, it has less energy, it will make do with male flowers, and can continue to accumulate reserves in its roots so that, next year, it can produce female flowers.
No, but isn’t nature absolutely FASCINATING? Plants that can change sex at will, as well as making little vampires of themselves!
“OK, but where’s the damn troll umbrella?”
Well, well, well, here’s the thing: the older the individual, the larger the specimen it will produce in the years when it makes female flowers. That’s why the same small Jack-in-the-pulpit can grow 20 centimetres year after year, then suddenly grow over a metre tall one summer… before returning to 20 centimetres the next year.
It’s not the fertilizer or the weather or some magic formula that has created a plant worthy of the enchanted forest; it’s the plant itself, all by itself, that has reached a venerable age and a considerable amount of energy in its rhizome.