This month we’re looking at some of PEI’s native wildflowers. So far, we’ve seen showy (Trilliums and Cherries), subtle (Blue-eyed Grass), and sneaky (Bunchberry). Today we have strange: Jack-in-the-pulpit (Arisaema triphyllum).
Jack-in-the-pulpit is common on PEI and most often found in rich, damp soil along streams and rivers. This is a tall plant – leaves can be up to 60 cm (2 feet) high – that looks like it would be more at home in a tropical jungle than our temperate forest. Each plant has one or two leaves, but each leaf is divided into three parts making it look a bit like the three leaves of Trillium. You can easily tell the two plants apart by size, number of leaves, and leaf veins: Jack-in-the-pulpit has veins that branch out from the midline, whereas Trillium’s leaf veins all arise from the base.
While Jack-in-the-pulpit’s leaves may resemble other plants, its flower is unmistakable. The green and cream striped part is the ‘pulpit’ – a modified leaf (called a spathe) that helps protect the inner flowers and guide pollinators to them. Inside is the finger-like ‘Jack’, a type of flower (called a spadix) comprised of dozens of tiny florets. Once pollinated, the flowers become distinctive red berries that are used by birds and other wildlife but are toxic to humans. All parts of Jack-in-the-pulpit contain calcium oxalate which can irritate skin, so it’s best not to touch it either.
This species is dioecious, meaning not all individuals are Jacks – some are Jills. Unlike most plants, Jack-in-the-pulpit can switch between male and female forms throughout its life. This isn’t just a cool party trick, but rather a very useful adaptation! Female plants produce fruit and seeds, which takes a lot of energy. All young plants start out as male, likely because their small size and root mass doesn’t provide the energy needed for flowering and seed set. As this perennial plant ages and grows, the root gets larger and able to store more energy; once large enough, it switches to female.
This isn’t a one-way street, and plants can return to male if necessary. If poor growing years arise – dry conditions or too much sunlight hitting this shade-loving species, for example – female Jack-in-the-pulpit can become male to conserve energy and increase chances for survival. Additionally, if one population of plants becomes too female-dominated, some may switch back to male to restore the balance.
This reproductive strategy is called ‘sequential hermaphrodism’ and is also found in Striped Maple (Acer pensylvanicum). Jack-in-the-pulpit is not only an unusual-looking wildflower, its reproductive adaptation is a very cool part of PEI untamed!