“Dig, dig, dig” to find the little-known facts hidden behind the lyrics!

"Dig and dig in the little garden, plant little seeds, and grow little flowers..."

This nursery rhyme has been very popular recently, but did you know that it can also reveal a lot of interesting plant knowledge? Let’s take a look at it together~

01

"Little Seeds" and "Little Flowers"

Small seeds and small flowers seem to be very common. The wild flowers and weeds around us are mostly such examples.

In early spring, there is a kind of blooming blue flower called "ground grass". As the name suggests, this small wild grass grows close to the ground. The plant itself is not very big, and the flowers are only two or three millimeters.

The picture is copyrighted by the library and is not authorized for reproduction

Such a small flower, such a small plant, cannot grow larger seeds - the seeds of ground ivy are only 1 mm in size .

The advantage of small flowers and small seeds is that they consume nutrients. The flowering period of ground vegetables is very long, and they can bloom almost all the time except in winter. Although each flower can only produce 4 seeds, such consumption is enough for them to fight a protracted war.

If we really want to talk about extreme examples, we have to bring up orchids. The seeds of orchids are as small as dust . Since the seeds are small, how big are the flowers?

Many nature lovers in southern China have a hobby. Every spring, they look for three kinds of orchids in the lawns: the stigmata, the line-column orchid , and the beautiful crown orchid . We jokingly call them the "three treasures of the lawn." Their flowers are very small, so they must be "looked for." For example , the stigmata plant is less than 10 cm tall, with a string of small pink flowers arranged in a spiral on a slender style, and the size of a single flower is less than 1 cm .

Corolla. Copyrighted image from the gallery, no permission to reprint

Line column orchid. Copyright image, no permission to reprint

Image source: Wikipedia

02

"Big seeds" and "big flowers"

In some tropical areas in southern China, a gorgeous street tree, the royal poinciana , is often planted in green belts. When it blooms, the fiery red flowers burn brightly on the rows of trees. Such tall trees are not stingy in spending money on flowering, and each flower can be 10 centimeters in diameter .

The big red flowers are for birds. The big cup-like flowers are filled with nectar for the birds, and the birds spread pollen for the Delonix regia.

Even more outstanding are their seeds. As a member of the leguminous family, the royal poinciana also produces pods, but these pods are really big, more than half a meter long, and the seeds are nearly 2 centimeters.

Royal Poinciana. Copyrighted image, unauthorized reproduction

The seeds of the royal poinciana tree. The picture is copyrighted by the library and is not authorized for reproduction.

Tropical plants always stand out for their large flowers and seeds.

In addition to some Fabaceae, the wood butterfly of Bignoniaceae also looks special. Although the flower is not as big as the Delonix regia, it is also 5 to 6 cm in size. Their fruits are also long columnar, and the fruit pods of the wood butterfly can reach more than one meter in length . When the fruit pods are ripe, they will split open to reveal the seeds inside.

The name of the wood butterfly comes from the appearance of the seed - thin wings extend from the periphery of the seed, and the diameter of the seed and the wings can reach 500 to 600 centimeters. When the seed is spread, the seed is like a butterfly flying lightly in the air.

Wood butterfly. Image source: Wikipedia

Seeds of the wood butterfly. Image source: Wikipedia

03

"Small seeds" and "big flowers"

How small can a seed be? In our culture, sesame is often used as a metaphor for smallness, such as small officials and small things. However, when it comes to smallness, sesame is not even on the list. Orchid seeds are at the top of the list, because as mentioned in the previous article, orchid seeds are probably smaller than dust.

Although many flowers in the orchid family have small seeds and small flowers, there are also quite a few large flowers, such as the Tibetan Cyperus , a specialty of high altitudes, which can be the size of a palm.

Tibetan Cypripedium. Copyrighted image, unauthorized reproduction

The giant comet orchid , which Darwin made famous, has a palm-sized flower and a spur more than half a meter long, which makes it a giant among orchids. However, such a large flower does not prevent the orchid's seeds from being so small. The ratio of the size of orchid seeds to the size of flowers is probably the best in the plant kingdom.

Giant Comet Orchid. Image source: South China Botanical Garden, Chinese Academy of Sciences

The cuckoo is even more exaggerated.

Azalea seeds are not much bigger than orchid seeds, but the flowers of the genus Rhododendron are generally not smaller than orchids. Even the giant among rhododendrons, the Magnolia Rhododendron , can be 10 centimeters in size. Not only is the ratio of flower to seed exaggerated, who would have thought that this tiny seed could grow into a giant tree 10 meters tall .

Magnolia azalea. Image source: Plant Science Data Center, Chinese Academy of Sciences

Whether it is orchid seeds or azalea seeds, they all adopt the "sea of ​​seeds planting strategy" - no matter whether they survive or not, they are scattered first.

Each orchid seed is only a few microns in size. To our naked eyes, it looks like a ball of dust. The tiny seeds are more easily blown away by the wind.

Unlike other plant seeds, orchid seeds do not have the nutritional reserves needed for germination for their offspring, but they have signed a "friendly alliance treaty" with fungi - the fungi provide the orchid with water and minerals for germination and subsequent growth, and the orchid shares the nutrients from photosynthesis with the fungi. Relying on this alliance, orchids are extremely concise in the arrangement of seeds, resulting in such a miniature size.

In the Lingnan region, the Kapok tree is a popular street tree. In early spring, before the leaves grow out, the tree is covered with red flowers. The Kapok tree is sturdy and tall, and the flowers are not small, with a diameter of about 10 cm.

It is also because of this huge flower that the kapok tree frequently appears on TV. When the kapok flower withers, the entire flower falls from the branch. If there happens to be an unfortunate passerby under the tree, the falling flowers from the sky can knock him unconscious.

Kapok. Copyrighted image, unauthorized reproduction

Kapok got its name from its seeds, which are wrapped in a thick "cotton coat". Ancient people would use these hairs as fillings for clothes and quilts. The seeds are not small in the plant world, about 1 cm in size , but they are much smaller than kapok.

04

"Big seeds" and "small flowers"

The coconut is one of the most extreme fruits with large seeds and small flowers. We have all tasted the deliciousness of coconut. The flower of coconut is very small, only about 3 cm in size . Who would have thought that such a small flower can produce a large coconut with a diameter of 20 to 30 cm that we hold and suck.

Coconut flower. Copyright image, no permission to reprint

05

"Extraordinary large seeds" and "tiny flowers"

If we want to be more extreme, we might as well bring out the world's largest seed - the sea coconut . Although they are both called "coconuts", the sea coconut is not the same type of coconut we eat. The diameter of the sea coconut seed can reach 40 to 50 centimeters and the maximum weight can reach 25 kilograms.

Although the male inflorescence of the sea coconut can be as long as 1 to 2 meters, the flowers are very small, with a diameter of about 1 centimeter.

The male flowers and fruits of the sea coconut. The picture comes from the Internet

Because on the island, the wind is strong, and it is difficult for pollinating insects to perform their mission in this environment. Since there is plenty of wind, we can make good use of it. Flowers spread by wind do not need bright colors and huge petals, but instead have giant inflorescences composed of hundreds of small flowers, and the pollen supply is also sufficient. Pollen is flying, and it is a good deal if you can get one of them.

The female flowers of the sea coconut are a bit bigger, about 10 centimeters , but compared with the huge seeds, I'm afraid I can't say they are "big"...

The island environment also shapes the size of the seeds. Coconuts grown on the seaside need to travel across the ocean. Seeds that are too small will be beaten to pieces by the waves, while large seeds are more stable during drifting and can store enough nutrients for long sea journeys.

Author: Ye Zhengrong, science writer

Reviewer: Wang Kang, Director of the North Science Museum of the National Botanical Garden, Professor-level Senior Engineer