Fruit trees?

Banana (trees?) hang over the fence in my sister’s backyard in Los Angeles.  While they are as big as some small trees, bananas are really just a very large herbaceous flowering plant.

bananas

The fence is about 5 1/2 feet tall, and the bananas approximately double that. You can just barely see an overly ripe bunch in the right-center of the photo above the fence.

Each stalk that arises from an underground corm produces one flowering stem that develop into the fingers of bananas we later purchase at the grocery store. When that stalk has ripened its fruit, it withers and falls, and a new “baby banana” shoot starts to grow up from the corm.  So banana plants are really herbaceous perennials.

banana fingers-very ripe

These bananas were beyond ripe and almost mushy, but very sweet tasting. The parent stalk behind the clump of bananas is already yellowing and will soon fall down.

Bananas originated in the Indomalayan-Australian region of the world. Varieities were selected that could develop fruits without seeds and without fertilization of the flowers for cultivation, so modern bananas develop directly from the first, female-only flowers on the flower stalk (i.e., parthenocarpic development).

banana fingers

Green (unripe) banana fingers grow in whorls around the flower stem. The lower part of that stem that would produce sterile and male-only flowers has been broken off.  The fleshy part that develops into the banana arises from the flower’s ovary; dried-up remnants of petals persist at the outer tips of the fruit. 

banana fingers and male flowers

When the female-only flowers have developed into banana fingers, the flower stalk elongates and produces additional sets of flowers in double rows — first, a set of sterile flowers with both stigma and anthers, and then lower down, rows of male-only flowers.

sterile banana flowers

I think these are the sterile banana flowers that contain both female and male reproductive organs, but no pollen or ovules in the flowers. The stigmas (female) are the whitish spoon-shaped structures, and the anthers are the yellowish, reflexed structures.

Plant breeders have so successfully messed with the sex life of the banana plant, there is no purpose for these sterile or male-only flowers, and they are usually removed.  Their slimy, sticky residues are a nuisance to clean up anyway.

The bananas in the Los Angeles backyards seem to be an untapped resource — there are no monkeys to harvest them, and the squirrels and birds seem to ignore them.

2 thoughts on “Fruit trees?

  1. What a really cool posting. I had no idea how bananas, one of my favorite fruits, grew. You managed to confuse me a bit with your detailed discussion of the sex life of bananas, but your photos are beautiful and helped me to understand somewhat better how bananas grow.

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