There are so many green radishes in the world, but isn't there a single one that blooms?

As one of the most successful indoor cultivated plants in the world, the pothos is almost synonymous with potted plants, but at the same time, it is also the most familiar stranger to us. The species of pothos (Epipremnum aureum) was published as early as 1880, but it is hard to imagine that it was not until 2004 that its origin was determined to be Moorea in the Society Islands of French Polynesia.

What’s even more mysterious is that the green ivy is an overly reserved plant. Although it has spread to tropical regions around the world, there was only one definite record of its flowering in 1962. It was not until 2016 that people discovered the secret of its flowering.

Are you really familiar with this plant which is very common around us?

Want to know why the green radish doesn't bloom? See below | pixabay

“I will climb up step by step”

I remember when I was a kid, I saw potted green radish with big leaves sold in the flower market. I couldn’t believe it was green radish. If you search for pictures of green radish, you will get two completely different types: one with small and dense leaves, and one with leaves as big as a cattail leaf fan. They look like two different plants - this is actually the dimorphic leaf phenomenon that many vines have.

Many vines often germinate in the understory of a forest with extremely low light levels. Growing small and numerous leaves can reduce energy consumption and increase the efficiency of photosynthesis. At this time, they will spread out and stretch out their branches to find a suitable object to cling to. Once they find something to cling to, these vines will quickly change their strategy and begin to climb upwards, heading towards the canopy of the forest, while growing larger leaves. Many vines around us have this survival strategy, such as ivy, Ficus microcarpa (jelly fruit), etc.

In the game "Travel Frog", the thing climbing on the outer wall of the frog's house is the fig. The fig is a plant of the genus Ficus, which can produce cryptogams similar to figs | 旅かえる；Ixitixel & Vincent Cheng / wikimedia

The same is true for the green ivy. When it is not yet an adult and the plant has not yet climbed, it will continue to grow smaller heart-shaped leaves, while the stem continues to extend forward to find something to climb. Once it finds a tree trunk or a rock, it begins to grow upward, the stem quickly becomes thicker, and the leaves quickly become larger, as if it has become a different species.

The green radish in the greenhouse of Wisley Garden. You can see that the lower leaves are very small, while the upper leaves are very large. | Yu Tianyi

Manufacturers of large potted plants use palm columns (with bamboo inside and mesh fibers from palm trunks outside) to help the plants find something to climb on and grow thick stems and large leaves. The outer layer of the palm column is loose and porous, which allows the aerial roots of the plants to take root on the column and absorb water to provide moisture to the aerial roots.

Potted plant with palm column | Mokkie / wikimedia

The dense aerial roots of the Pothos | Forest & Kim Starr

In fact, there are many plants with dimorphic leaves in the Araceae family, where the green radish belongs. However, although it is called dimorphic leaves, there are actually more than two types. If you look closely at a Monstera, you will find that the leaves range from small to large, with edges ranging from unbroken to 1-3 lobes and then to more than 10 lobes. Even more exaggerated is the Syngonium, whose leaves look like the dripping Guanyin (Alocasia or taro) when young. When it grows a little bigger, the lobes at the base of the leaves begin to become pointed. After finding something to cling to, the leaves will quickly split, some with 3 lobes, and some with 5 lobes in a palm shape.

Monstera deliciosa beside Luochi in Liuhou Park, Liuzhou, Guangxi | Wula Kuanke/ wikimedia

The secret of not blooming

The flower of the green radish has always been a mystery. Because no one knows what its flower looks like, the classification of the green radish has always been uncertain, and its Latin scientific name has been changed three or four times.

Since the first discovery of the green radish was published as Pothos aureus by botanists, its English name has always been called pothos, but in fact, it is not closely related to the genus Pothos and does not look much like it. It was not until 1962 that people finally observed the flower of the green radish and finally moved it to the genus Epipremnum.

However, since that crucial flowering in 1962, there has been no definite record of the flowering of the green radish in the world, until an article in 2016 finally revealed the secret of the green radish's failure to bloom. Scientists have discovered that the green radish lacks the gene for synthesizing gibberellins (EaGA3ox1) and the gene for identifying flower bud differentiation (EaLFY) - because gibberellins are important substances that control the formation of flower buds and promote flowering in plants, the green radish will never bloom under natural conditions. In the experiment, the author sprayed the green radish with gibberellins (GA3) for a long time, and the result was amazing: the immature plants that did not find anything to cling to bloom first.

The middle of the picture shows the flower of the green radish induced by gibberellin. It has the typical spathe and spadix of the Araceae family | Chiu-Yueh Hung et al. / Nature (2016)

What? Have you ever killed a green radish?

Despite its lack of flowering, the pothos has become one of the most successful houseplants. One reason for its success is that it is so easy to keep.

The living environment that humans like happens to be the growth environment that most plants don't like. There are very few plants that can tolerate indoor environments, so most indoor potted plants are species that adapt to the moist and dark environment under the canopy of the forest. The green radish is one of the most suitable plants for indoor environments with a lack of light and air circulation, so if you can kill the green radish, either put it in a very unsuitable environment, or give up growing flowers.

Young shoots and leaves of indoor climbing pothos | Jerzy Opioła / wikimedia

So, what kind of environment is the green radish very unsuitable? Although the green radish is shade-tolerant and moisture-tolerant, the soil in its native place is loose humus, so the green radish does not like hard and compacted clay. The pot soil can temporarily accumulate water, but it must have good drainage.

In addition, the green ivy is afraid of long-term direct sunlight. Its native environment is under the dark rainforest canopy, where direct light is difficult to reach. Long-term direct sunlight will cause the leaves to turn yellow and fall off, and strong direct sunlight in summer can even quickly burn the entire plant (don’t ask me how I know).

However, for variegated varieties, only a certain amount of sunlight can maintain the bright contrast of the leaves. Long-term exposure to the shade will cause the leaves to turn green and the contrast is not obvious. Therefore, variegated varieties need more bright scattered light. The Flora of China records that "if planted in a too dark place, the beautiful spots on the leaves will easily disappear", which actually describes the variegated varieties of the green radish.

Pothos 'Golden Queen' | Joydeep / wikimedia

Another factor for the success of the green radish is that although it does not bloom, it has a strong asexual reproduction ability. The cuttings of the green radish are extremely easy to survive. Each stem node on the branch can grow aerial roots. As long as the aerial roots are successfully rooted, they will grow rapidly. A small section of the green radish branch can quickly grow into a large pot.

Since the green radish is dimorphic, it will grow very long branches at a certain stage in search of something to cling to. The leaves of this branch are usually sparse, which affects the appearance. If you just want to keep the leaves of your green radish small, you can just cut off the elongated branches and use them for cuttings.

Author: Yu Tianyi

This article comes from the Species Calendar, welcome to forward

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