I’ve been curious about this plant ever since I ate my first Panamanian tamale wrapped in one of its leaves.
Luckily, the family that is helping me with my Spanish gave me a grand tour of their property last week, and they presented me with many plant cuttings and fruits and other wonders from their place. This plant was among the gifts.
One of the first things I noticed after potting it up was that the leaves folded up:
Being new to botany and gardening, I thought, well, it must be transplant shock. The next morning, the leaves were open again, and I breathed a sigh of relief. Okay, it’s not going to die on me. But then by noon, the leaves had folded up again.
It was time to figure out what is going on.
It did not take long to find the scientific name of the plant because the woman who gave it to me also was kind enough to write down its name in Spanish – bija, or bijao (for the leaf). I found the word bijagua in the index of my copy of Tropical Plants of Costa Rica, and there, on page 98, was my plant.
The reddish parts are bracts, and they form the shape of the flower cluster, or inflorescence. An individual flower has been pulled out of one of the bracts and sits between the two stems on the right. The flowers appear only after the plants are mature and much taller than the one in my pot.
Calathea lutea belongs to the family Marantaceae, which is named for Bartolommeo Maranti, a 16th century Venetian botanist. Since the family is named after a person, we don’t get a description of the plant from the name, but it didn’t take long at Wikipedia to discover that Marantaceae is sometimes called the “prayer-plant family” because of the way the plants fold their leaves.
There’s a great description of this leaf behavior at the page on Form and Photosynthesis by Thomas J. Herbert, who has studied leaf movement in Calathea lutea in detail. According to Herbert, the leaf surface becomes vertical at night (this is called nyctinasty, in botanical language) and then more horizontal in the morning. By noon they’ve moved into a vertical position again – and they’ve folded their leaves. This time the movement is called paraheliotropism. Nyctinasty is activated by the red-sensitive pigment that causes a plant to flower in the spring because the days are growing longer or in the fall because the days are growing shorter. Heliotropism is activated by a blue-sensitive pigment.
But back to my original interest in this plant – as food wrapper. You can see from the first image that the leaves are large and attractive. They also have a waxy surface underneath, which can be seen when the leaves are folded. It’s always fun to guess why the first person decided to try using a plant in a new way. For one thing, there are plenty of these plants around – it is a pioneer species in the tropics, so it’s abundant in open areas. For another, to me, the leaves just look clean, and they’re plenty large enough to wrap food in…so….
I don’t yet know how to make tamales, but I do now know how to make Panamanian tortillas folded in one of these leaves. You simply place the waxy side of the leaf down on a skillet, place the tortillas on the leaf, and fold the top half of the leaf over the tortillas. Place a lid on top to hold the leaf in place and cook over a very low flame for 40 minutes. Turn and cook for an additional 30 minutes. They’re done.
You’ll notice that I haven’t given the recipe for the tortillas themselves – that’s a family secret!
Update, 5 June 2012: The secret is out. Here’s a link to that family’s recipe for Panamanian tortillas.