Tuesday, April 17, 2012

Peekaboo! I see you!






Species name: Arisaema triphyllum

Common name: Jack-in-the-pulpit, bog onion, brown dragon, Indian turnip

Location: Ontario

Jack in the pulpit flowers are great examples of exceptions in the plant world, which is one of the reasons why I like them so much. It is another example of a native eastern North American plant. We have these growing in our back yard, which confused me at first (like they do many people) since I mistook them for poison ivy and ripped out all of the leaves one year (with gloves on!). The leaves of poison ivy and jack in the pulpit are both what are called "trifolate", which means there are three leaflets coming out of each "leaf point" on the stem. Once this plant starts to flower, however, is very obvious that it's not poison ivy! Silly me. Like the last plant in this blog, hyacinth, jack in the pulpit also grows from a corm.

One of the amazing things about this plant is just how variable it can be depending on environmental conditions, and what type of genetic variation it contains. The flowers themselves can range in size from 12-36 cm tall, and can be anywhere from pure green (like in the photo) to green with dark brown (almost purple) stripes. The "jack" on the inside can also be bright green or dark purple-brown, or anywhere in between. The plants themselves can be from 30-65 cm tall, depending on nutrient levels of the soil.

In general, a good rule to use to figure out if a plant is a monocot (in other words, most closely related to grasses) or a dicot (in other words, most closely related to an oak tree) is by the shape of their leaves and the number of flower parts. In general, monocots have long and thin leaves with parallel veins and flowers with flower parts (petals, sepals, stamens and stigmas) in multiples of three. Dicots have broad leaves with net-like veins and flower parts in multiples of either fours or fives. Jack in the pulpit, then, seems to be a dicot. Its leaves are broad and have net-like veins, and unless you have a very powerful hand lens it's impossible to tell if flower parts are in multiples of 3s or 4-5s. Unfortunately...that would be incorrect. This is a monocot! One unusual group of monocots is the family Araceae, which includes the peace lily (a common ornamental plant, often used as an aquatic plant in wedding centrepieces). They have broad leaves with (mostly) parallel veins (but some are cross-wise) and a specific type of flower called the spathe and spadix. Here, "Jack" would be the spadix and his pulpit would be the spathe. If you zoom in on the spadix, you would see that it's actually a multi-flowered flower head (called an inflorescence), with each little facet on the spadix being one flower. Neat!

But, of course, the uniqueness of this plant doesn't stop there. This is also a great plant to demonstrate all of the unique evolutionary mechanisms plants have derived to avoid self-pollination or inbreeding. There are separate male and female flowers on the spadix, but never both at the same time. Usually the plant starts with predominantly male flowers (if there are female flowers, they are not mature yet) that are producing pollen. Flies are attracted to the spadix because they are much warmer than the ambient air (thanks to the spathe), and they have a rather...unpleasant smell. The fly is covered in pollen, then travels to another flower. If the plant plays its cards right, the next flower will be predominantly female flowers (if there are male flowers, they are no longer mature) which are receptive to receiving pollen. The fly deposits the pollen onto the stigmas, and pollination occurs. Even neater!

This plant is absolutely toxic if consumed raw (it contains calcium oxalate crystals which can perforate the digestive tract), but is actually often cooked as a root crop like you would cook potatoes (but boiled a bit longer because they're much tougher) and eaten. I have never tried it so I can't vouch for what it would taste like, but I can't imagine it would be too flavourful. Native North American people often used this plant as a medicine to treat sore eyes, rheumatism, bronchitis, snake bites, and to induce sterility. Whether or not it's an effective treatment against any of these I have no idea. I wouldn't recommend experimenting.