Bananas, plantains; pollination, parthenocarpy

How do you tell the difference between a plantain and a banana?

It’s pretty straightforward when you walk into a fruit and vegetable stand and see large, green plantains next to smaller, yellow bananas.

Plantains are starchy and are cooked like starches. Bananas can be cooked, too, but the bananas we know from temperate climates are “dessert” bananas and usually are eaten raw.

But it’s not so easy to tell them apart when you look at two adjacent, growing plants, one plantain, the other banana.

In this image, all the plants are banana plants except the two end plants in the middle row. Those are plantain plants.

On closer examination, here’s a plantain plant on the left and a banana plant on the right.

Without going into further detail at the moment, the only difference I can tell between them is their size, which reflects the rate at which they’ve grown. (The angle of the leaves depends on how long ago the leaf unfurled and is not, as far as I know, a distinguishing characteristic.) We planted the bananas about a year ago and the plantains about six months ago. The plantains are already much taller than the bananas.

So what is the difference between plantains and bananas?

These days I turn first to my book, A Guide to Tropical Plants of Costa Rica, for an overview. There I find that both are members of the genus Musa, family Musaceae. There are hundreds of banana forms and cultivars, and there are about 40 wild species of Musa. The plantain is a hybrid of the species M. acuminata and M. balbisiana. The growing banana pictured in that book is M. acuminata, from which the commercial banana was cultivated.

That information tells me that the plants are reliably genetically different, but it doesn’t tell me how to tell which plant is which.

Our local Panamanian friends have educated us in the ways bananas or plantains grow. You obtain a shoot (a “baby”) from a friend who has a banana or plantain plant. The shoot is actually a pseudostem growing from an underground stem or corm. As the original shoot matures, another shoot, or baby, may begin growing from the underground corm.

Eventually the original shoot will produce a flower (an inflorescence, actually) which will produce one stalk of bananas or plantains and then will die. After you harvest your bananas, you cut back the original shoot and wait for the baby shoot to mature.

That information tells me the plants grow in the same way, but it doesn’t tell me how to tell which plant is which.

My book explains to me that the fruits develop without pollination and without seeds, a process called parthenocarpy. This multisyllabic word comes from the Greek parthenos, which means virgin, and karpos, which means fruit. So there is no pollination, no fertilization, no seeds. Yet the plant produces both nectar and male and female flowers.

Those flowers have their own karma. The first 5-15 rows on the stalk are female flowers and these develop into fruit. The next few rows are sterile flowers with abortive male and female parts, and the last rows are flowers with normal stamens but abortive ovaries. These latter types of flower eventually drop off.

That information tells me that the biology and development seems to be so similar for both bananas and plantains that it’s not worth distinguishing, at least on a level suitable for a non-professional botanist.

Some friends have given me some suggestions on how to tell the plants apart – the color of the “trunk” is darker for a banana than for a plantain, there are 3 sides to a plantain but not to a banana, and the stem (petiole) of the leaf is paler for a plantain than for a banana. I’ve examined our plantain/banana side-by-side plants and my poor eyes just cannot find these distinctions, except possibly for a hint of a difference in the shading of the petiole.

So I’m going to have to grow accustomed to the plants, watch them produce year by year, and wait for the subtle differences to show themselves to me. Maybe one day….

8 thoughts on “Bananas, plantains; pollination, parthenocarpy”

  1. The way I like plantain best cooked as a dessert. Coming from the US, I wasn’t familiar with this interesting food, but its versatility makes it a real staple here in Panama,

  2. I received 2 bananas and 1 plantain, but the person who gave them to me bundled the three together. Right now one off the plants has fruit. I think it’s the plantain because the fruits seem large for just fruit bananas. I would love to grow some of the other bananas, like the lady bananas and the red ones. I’m looking forward to my “machos” as tostones when they are green and cooked with rum and sugar when riper, yum.
    Great info here and your other banana post. Thanks,

  3. Theresa in Merida,

    Nice to hear from you. Mmm, your thought of cooking tostones [plaintains (?) or bananas (?)] with rum and sugar sound great!

    Thanks for the idea.


  4. if plantain can actually reproduce without the female flower then what is the need of the flower?

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