Indian Corn Cob, Corn Cob Plant, Corncob Euphorbia, Corncob Cactus
Synonyms of Euphorbia mammillaris (7) (Updated on 12-22-22 from Plants of the World Online): Euphorbia enneagona Haw. (1803), Euphorbia erosa Willd. (1814), Euphorbia latimammillaris Croizat (1933), Euphorbia mammillaris var. spinosior A.Berger (1902), Euphorbia mammillaris var. submammillaris A.Berger (1902), Euphorbia platymammillaris Croizat (1932), Treisia erosa (Willd.) Haw. (1819)
Euphorbia mammillaris L. is the accepted scientific name for this species of Euphorbia. The genus and species were named and described as such by Carl von Linnaeus in the first edition of Species Plantarum in 1753.
As of 12-22-22 when this page was last updated, Plants of the World Online lists 2,087 species in the Euphorbia genus. It is a member of the plant family Euphorbiaceae with 227 genera. Those numbers could change as updates are made on POWO. The number of species in the genus fluctuates often.
The genus, and family for that matter, consists of plant species from most of the world. While some may not be that abundant, others are quite common. There are herbaceous plants (annuals, perennials, wildflowers, herbs, etc.), trees, shrubs, and succulents in the genus. Euphorbia mammillaris is a succulent species, almost cactus-like, from South Africa. Yeah, I know… Cactus are succulents, but not all succulents are cacti… 🙂
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I picked up this Euphorbia mammillaris cutting on March 29, 2019. I have had a few other Euphorbia species as companions and we have always gotten along very well. I like the small leaves and there were remnants of its small yellow flowers when I brought it home.
Origin: South Africa
Zones: USDA Zones 8b-11 (15-40° F)
Size: 6-18” or “more” tall. HMMM…
Light: Sun to part shade
Soil: Very well-draining soil. Potting soil amended with additional pumice or chicken grit and perlite.
Water: Regular watering during the summer. Very little, if any, during the winter.
Euphorbia mammillaris on 3-30-19, #557-10.
This species has 7-17 ribs with hexagonal tubercles in vertical rows resembling an ear of corn. It also has a few spines. The tubercles swell with normal watering and shrink during dry periods.
There is not much information online about the Euphorbia mammillaris for some reason. It is a very interesting plant in my opinion.
The Llifle (Encyclopedia of Living Forms) website has more than any other website about this species and growing recommendations.
Although most information online says this plant grows up to maybe 18″ tall, Llifle also says…
“…young plants are happy growing indoors, where they can easily reach the ceiling.”
“It is a moderately fast grower, and will quickly become large landscape masterpieces in just 3-5 years.”
SOOOO… It will be interesting to see what this plant does firsthand.
Description: It is a short-stemmed dioecious shrublet producing a dense cluster.
Stem: Thick deep green,, erect, simple and ribbed, that in cultivated plants may branch above, 1, 5-6 cm in diameter.
Mature: Height 20-35 cm tall. Usually, there are many club-like lateral branches, starting about 10 cm and arches upward.
Ribs: 7-17, with hexagonal crowded tubercles set in vertical rows after the manner of an ear of corn and separated by horizontal groves.
Spines: Occasionally present and scattered, thick, blunt, and whitish, up to 1 cm long. The “spines” are the solitary sterile peduncles.
Leaves: Small, ephemeral (meaning they last for a short time).
Flowers: Produces yellow solitary cyathia at the top of each stem. Peduncle +/- 2 mm long with several bracts up to 3 mm long. Nectar glands elliptic, separate, yellow-green to purplish.
Blooming season: Late winter to early summer.
Fruits: Obtusely lobed, up to 6 mm in diameter, subsessile.
Remarks: Euphorbia fimbriata is similar to E. mammillaria but has conical stem tubercles.
I had to move the potted plants inside for the winter on October 11 (2019) because an “F” was in the forecast. As always, I photograph and measure the cactus and most of the succulents. The Euphorbia mammillaris measured 5 3/4″ tall. I didn’t measure it when I first put in the potting soil so I have nothing to compare it to. I do know it is growing, though.
There are a lot of leaves on the upper part of the stem which will fall off at some point. Their leaves are ephemeral which means they only last for a period of time but they will regrow when the time is right. That makes it interesting to grow this plant.
I am kind of running out of words to say…
Oh, the spines… It does have a few spines toward the base of the plant and side branches.
I had to bring the plants inside for the winter on 10-15-20 because an “F” was in the forecast. As always I took photos and measurements. The main stem of the Euphorbia mammillaris measured 8″ tall so it is doing quite well.
I really like the combination of leaves and thorns.
The Euphorbia mammillaris has grown from 8″ tall to 11 3/4″ tall since last October 17. It is 6″ taller since October 2019. I will admit it looks weird the way the stem is wide, then thin, then wide again.
Even though it is somewhat weird, it is still a neat plant.
The Euphorbia mammillaris is still alive and well, but the stems are turning brown. I’m not sure, but think it is a natural thing called “trunking”. I may cut the stems and try regrowing it… It isn’t very photogenic like it is.
Be sure to click on the links below for further information about growing this plant. Llifle has a lot of good information. There is also a variegated form of this species.
I hope you enjoyed this page and maybe found it useful. If you have any comments, questions or suggestions, I would like to hear from you. Please click on “like” if you visited this page. It helps us bloggers stay motivated. 🙂 You can check out the links below for further reading. The links take you directly to the genus and species of this plant.
Thank you! I haven’t had much success in finding info on this plant either… I got the variegated one (I think). It’s light green..almost white! I got it from Leaf and Clay. Very cute and I’m excited to see them grow ^_^ I agree those little leaves are really cute and really weird for the cactus to have both leaves and thorns…and very few thorns here and there lol very random! Keep posting! Love.
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Hello Bluemoon! Glad you have one of these and a variegated one at that! It isn’t a cactus, though. 🙂 It is one of those plants that look like a cactus but is a succulent. Remember, cactus are succulents, but not all succulents are cactus. 🙂 I will keep writing because of people like you. Take care and thanks for the comment!