Colocasia antiquorum/fontanesii ‘Black Stem’/Black Stem Taro/GEEZ!!!

Colocasia antiquorum/fontanesii ‘Black Stem’ on 6-2-12, #95-30.

Black Stem Elephant Ear, Black Taro, ETC!
Colocasia antiquorum
kol-oh-KAY-see-uh an-ti-KWOR-um
Colocasia fontanesii
kol-oh-KAY-see-uh fon-tan-EZ-ee-eye
Colocasia antiquorum var. fontanesii (or visa versa)
Colocasia esculenta

According to The Plant List, Colocasia antiquorum Schott is the correct and accepted name for this species of Elephant Ear. It was first documented by Heinrich Wilhelm Schott in Meletemata Botanica in 1832. The synonym’s scientific name is Colocasia fontanesii Schott described by the SAME man in Oesterreichisches Botanisches Wochenblatt 1854. SO, wouldn’t this man have seen both and could tell the difference?

I bought my Colocasia antiquorum ‘Black Stem’ from Brent & Becky’s in the spring of 2012. I also bought an Alocasia ‘Black Stem’ from Wellspring Gardens. I thought maybe they were the same plant, but sure enough, they were different. The Colocasia leaves pointed downward and the Alocasia pointed upward. Very strange that there is a species of Alocasia and Colocasia that look so much alike except for the direction the leaves point…

Although The Plant List says that Colocasia fontanesii is a synonym of Colocasia antiquorum, many websites, including Dave’s Garden, are still saying that the black Stem is a Colocasia fontanesii. They state that Colocasia esculenta is a synonym of this plant, but no mention of Colocasia antiquorum. SO, I searched Dave’s Garden for Colocasia antiquorum. I find Colocasia antiquorum ‘Illustris’, ’Black Runner’… Dave’s Garden is SO SSSSSLLLLLOOOOOWWWWW these days I got frustrated and stopped after the third page.

I did a Google Search and typed in Colocasia ‘Black Stem’. Here’s what I see:
American Meadows says Colocasia fontanesii-Elephant Ear Black Stem
Fine Gardening says Colocasia esculenta ‘Fontanesii-Black stem elephant’s ear
Plant Delights says: Colocasia ‘Fontanesii’-Black Stem Elephant Ear
Plants Database (National Gardening Association) says Colocasia fontanesii is the accepted scientific name and lists four synonyms I didn’t see anywhere else. Just as confusing…
Ball Seed Company even says Colocasia fontanesii with Black Stem as a common name.


Colocasia antiquorum/fontanesii-Black Stem Taro on 7-19-12, #111-10.

The Wikipedia says both Colocasia antiquorum and Colocasia fontanesii are accepted names. When I click on Colocasia antiquorum it redirects to Eddoe (what the edible bulbs/tubers are called). When I click on Colocasia fontanesii I get noting. Besides the name, it says they are from Yunnan, the eastern Himalayas, northern Indochina. My fiance is from the Phillippines and we have had several discussions about the ‘taro” they eat there. She says that some of them are white, some are purple, some are pink, and some are white with purple specks… AH HA!!! Now, even though you can read it for yourself, the Wikipedia says the Eddoe seemed to have been developed in Japan or China and taken to the West Indies. Farther down it says…. OK, I better stop. Anyway, it says, QUOTE, “They are the most commonly eaten inhames/carás in the states of São Paulo, Rio de Janeiro and Espírito Santo, as well as surrounding regions of all. They are also fairly common in Northeastern Brazil, where they might be called batata (literally “potato”), but less so than true yams of the genus Colocasia. According to Brazilian folk knowledge, the eddoes most appropriate to be cooked are those that are more deeply pink, or at least pinkish lavender, in the area where the leaves were cut.” SO, wouldn’t you think that the Black Stem Taro would produce purple bulbs? How is a bulb formed and what makes it get bigger? WAIT A MINUTE!!!! Colocasia in Brazil? Now how did an Asian species get to Brazil? Someday, VERY SOON, I am going to the Philippines and I am going to find not only the different colored taro but also the plants they come from…

SO, wouldn’t you think that the Black Stem Taro would produce purple bulbs? How is a bulb formed and what makes it get bigger? As the petioles die the bulbs get larger by adding another layer.

Seriously, I have been way confused. In the first place, I don’t even remember what Brent and Becky’s website called them when I purchased it, 5 years have passed. I think maybe it said Colocasia fontanesii ‘Black Stem’, but it could have said antiquorum. Then, in 2010, The Plant List changed and said Colocasia antiquorum had become a synonym of Colocasia esculenta… I was VERY confused because “Black Stem” had hardly any characteristics that Colocasia esculenta have. The only one being, that I could tell, was that they were Colocasia. The purple petioles, smaller dark olive green leaves, smaller bulbs, nothing like a Colocasia esculenta. BUT, I changed the names I had with the photos. Then, when I started blogging again, for the third time, I saw where the name had changed AGAIN to Alocasia antiquorum… Well, at least they aren’t Colocasia esculenta anymore… Then there are the Colocasia esculenta ‘Tea Cups’, ‘Coffee Cups’, ‘Bikini Tini’, ‘Big Dipper’, etc. which all have the same features. They have the same dark petiole as the Black Stem plus the dark olive-green leaves. The only visible difference is their smaller cup-shaped leaves and they are supposed to be “cultivars’ of Colocasia esculenta. I think they are from Colocasia antiquorum/fontanesii not Colocasia esculenta. 

SO, personally, call them Colocasia antiquorum or fontanesii but please not Colocasia esculenta. How do they decide one is a synonym of another then change it back again? Why would they change the names if the plants look so much different to be different species in the first place?

SO, in my honest opinion, ‘Black Stem’ is not a cultivar name at all. Black Stem is a common name of either Colocasia antiquorum or Colocasia fontanesii.

If you have any comments, questions or suggestions (PLEASE), I would love to hear from you. Someday I will buy another Black Stem Colocasia and try them here in mid-Missouri. I think my experience with them would have been MUCH better if I started with larger plants.

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