Miniature Elephant Ear Surprise
On a recent morning walk to a corner of the orchard I had not visited recently, I nearly stumbled over a small white flower.
The morning sunlight shone through the hood, making a glow like candle-light.
Hoping it might be easy to identify, I ran to my borrowed copy of the Flora of Panama Checklist and Index and looked up Arum – the jack-in-the-pulpit genus – and found four species. It did not take long to discover that this plant was none of the four species listed. So, being impatient and eager to get on with the ID, I turned to friend Carla, who did a little research and then turned to her friend Marianne, and behold we had a name – Xanthosoma mexicanum, previously known as Xanthosoma pilosa.
Sometimes (maybe I should say often) plant identification is just a matter of knowing who to turn to for help!
Edible and poisonous
The Xanthosoma genus is in the same family as the Arum, the Araceae Family. The family takes its name, in fact, from the Arum, a word that may have been derived from the Arabic word for fire, ar [Britannica]. That’s because the sap of and Arum plant and others in this family have a bitter, burning taste due to calcium-oxalate crystals and other toxins [Zuchowski]. These toxins can
…cause swelling and burning of the mouth and throat if eaten raw, as well as diarrhea and vomiting. The juice of the plants may irritate skin and eyes. [Zuchowski]
Cooking, however, can make the plant edible, and the tubers of some of them are used for food. Taro, called ñampi here in Panama, is in the Araceae family, and is used in several dishes of Panamanian cuisine.
Elephant ears
The best known Xanthosoma among gardeners in temperate climates is probably Xanthosoma roseum, the elephant ear. Those leaves may reach 200 cm in length. (Photo from wikipedia.)
Our little Xanthosoma from the orchard, Xanthosoma mexicanum, though, has leaves about 6 cm long. Please excuse its I-survived-the-weedeater appearance!
The yellow body
The word Xanthosoma was coined from xantho, meaning yellow, and soma, meaning body. I’m assuming the yellow body referred to is that part – the spadix – sticking up under the white hood – the spathe. And here we come to the whole reason for putting together this post.
Those two parts – the spadix and the spathe, defined below – are characteristic features of the Araceae family. They are the features of the calla lily, the jack-in-the-pulpit, and skunk cabbage that make the family so interesting to look at. I’ve been curious about these features for ages but only now have had the motivation to learn more about them.
The spadix continues down beneath the red throat of this little plant into the green belly below. I didn’t want to tear apart my one flower just to see what’s inside, so I borrowed an image from Discover Life, where the copyright allows use for personal and scientific reasons. Go there for the high resolution version of this image. The image below combines three views of the spadix and spathe – at the top is the complete structure, in the center is an enlarged view of the top portion of the spadix, and at the bottom is the portion of the spadix that is hidden in my plant.
The spadix and the spathe
A spadix is a cluster of tiny flowers crowded together on a thick, fleshy axis; the spathe is a modified leaf called a bract that either lies just below or partially encloses the spadix (wikipedia).
If we look closely at that upper section of the spadix, the section that’s a little reminiscent of immature corn on the cob, we see the male flowers of the plant. The tiny tufts sticking out between the hexagonal shapes are the anthers bearing the pollen grains.
The bottom portion of the spadix has the female flowers (the bright yellow “corn kernels”) on the left and a belt of sterile flowers (yellow, white, and purple) offered as a reward for pollinators on the right. The pollination story that follows is taken from the wikipedia article on Xanthosoma. It’s a neat tale.
When the top portion of the spathe first opens and exposes the spadix, it produces heat and releases a sweet scent that attracts its pollinators, which are scarab beetles of the Cyclocephala genus (drawing used by permission of Joe McGown).
These beetles presumably arrive covered with pollen from another Xanthosoma inflorescence and they remain in the spathe tube for 24 hours, pollinating the female flowers as they feed on the sterile area of the spadix.
On the second night, they come out of the tube and walk over the male flowers, getting covered by pollen, and then they fly on to another recently opened Xanthosoma.
Fruits start to develop while still sheltered by the spathe tube, and maturation takes months. When the fruits are mature, the spathe tube rolls open to reveal bright orange fruits and a velvety pink inner spathe surface.
Wow! I have no idea whether my single, isolated Xanthosoma mexicanum had a chance to be fertilized, but I’ll try to keep the weedeater away long enough to find out. Meantime, I have seen some other leaves of the plant on the ground nearby and I may try transplanting some to a safer area.
It is such a nice surprise to come upon a new plant. I am always thrilled when a little plant emerges where I didn’t expect it. Naturally one wants to know its name. You have done a very thorough research. I would rescue some and replant if it is possible which is not always the way with Australian native plants.
Wow! What a coincidence! I was on a hike on one of the beautiful trails with a couple friends here in Cerro Azul last Monday. We were at the edge of the river and saw this very same plant with a flower and were marveling at it. There were many other of the same plant around not yet flowering. I wanted to take a couple plants home with me and place them near the quebrada on the edge of our property but decided not to.
Now I know the rest of the story. Thanks!
Hi titania,
Thanks for commenting – I always appreciate your viewpoint. At this point I have indeed decided to try to rescue the plant. I hope it’s possible.
Michael – That’s great, no, it’s fantastic, that you saw the same thing at Cerro Azul. In fact, from what I’ve read, your habitat was a much more likely place to find Xanthosama mexicanum than our orchard! I haven’t really tracked it down, but I haven’t seen any references to it in Chiriqui.
Still, the plant was on the side of the orchard nearest our quebrada (seasonal spring for those not from Panama) so perhaps some creature ate a fruit and deposited the seed nearby. You’ve given me the idea to examine the quebrada area more closely – maybe I will see more plants there.
Wonderful and informative post. Thanks for sharing I love aroids!
Eric,
Thanks for commenting. Aroids are great to look at, aren’t they? Not always great to smell, though, as my friend Carla reminded me. Think of skunk cabbage for starters. It pays to be choosy.
There was a 50-foot bed of calla lilies in the house where I grew up, so I have a sentimental attachment to aroids. Thanks for sharing your discovery! I have some young tubers of other aroids that I’ve planted in the last few months. In a few years I hope to have some skunky but wonderfully outlandish aroids blooming!
I bought an elephant ear plant at a Grocery Outlet Store just because I thought it was really cool looking – it looked like plastic and I had no idea what it was – no identification tag in the plant. I’ve had it inside for about 2 years and it hasn’t done extremely well because I didn’t know how to work with it. Finally found out what it is and gave it more humidity and less sun – so I thought it was getting a new leaf, but it turns out to be one of these wonderful “jack-in-the-pulpit” things! In fact, a second one is growing now – but I doubt they will get fertilized, as I don’t have scarab beetles in my house! I’m so glad I found this site and at least know what these are. Nice surprise!
Karen,
Congratulations on your elephant ear plant! If you read through the comments above, you’ll find that Eric has mentioned the smell of certain plants in the family. I hope you don’t find the smell of your flowers too offensive.
I’m glad you found the right conditions for your plant, and thanks for the comment.