Phloeonomus looks at Seed Sizes and Growing Proteas
All you will need is a ruler to measure the seeds, and a pencil and paper to write down your results. Are the seeds of the Bot River - Protea compacta bigger than those of the obtusifolia the smallest? Write in and tell me.
Oh, if only life was that easy. My small beetle brain finds things so complicated. You see, protea seeds are not really "seeds" - they are fruit. Yes, I know you cannot eat them, but I am right. Seeds are baby plants, all safely wrapped up ready to germinate and grow into seedlings. But the hairy things people call protea seeds are not "seeds": they are the base of an old flower with the seed inside, so we must call them fruit. You have thus measured the fruit, but that is OK.
But not all fruit are good fruit - sometimes the fruit are empty: they are old flowers without a seed inside. That is why people are so worried when they plant all the protea "seeds" and nothing happens: everyone knows that if you plant dead flowers nothing will grow. But because people muddle up protea seeds and fruit, they get confused and expect dead flowers to grow! The Australians do not have to worry because in banksias the fruit is the follicle: this splits after a fire and the real seeds are released.
And if you thought "Oh, that's not too difficult", then I am afraid I am not finished. Richard also told us how rodents may eat protea fruits when they lie on the ground. Well, proteas are not stupid - they don't want all their seeds eaten! That is why the empty fruit looks just like the fruit with seeds in them. Rodents have to waste a lot of time looking for the few fruit with seeds inside! Sometimes it is easy to tell if a fruit has a seed inside, and other times it is very, very difficult. Can you see any difference among the fruit which you measured? If you got your fruit from a supplier you should only have fruit with seeds inside. If you took them from a seed head you should be able to see the difference: the fruit with seeds inside are a little fatter. Each seed head will only have a few fruit with seeds inside, even though there are hundreds of fruit.
But that is not all! Some proteas produce two types of empty fruit: one thinner than and one the same size as a fruit with seed inside. It is thus not surprising that rodents are not the only ones confused by the tricks proteas play to protect their few, precious seeds.
Why not plant the fruit you have measured? The best time to do so is April or May. You will need a tray filled with river- or building-sand, or a little cleared spot in a flower bed, some more sand and your Protea fruit (not the empty ones!).
(Step 1) Put the fruit on the ground and sprinkle a little sand on top, just enough to stop the wind from blowing the seeds away.
(Step 2) Water them and watch - what happens? The hairs on the fruit slowly close up. When it is dry the hairs hold the fruit above the very hot ground to stop them cooking to death. When it's wet the hairs let the fruit touch the ground and so they can absorb water.
(Step 3) You should water the fruit every few days. A cloth over the fruit will stop the soil from drying out and stop the fruit blowing away. When enough water is absorbed the seed inside the fruit will germinate. Between 18 and 30 days the root tip should appear and grow into the ground. As it grows it will lift the fruit into the air and split open the fruit revealing the "seed leaves".
(Step 4) The first two leaves on the seedling are the "seed leaves": these contain all the food for the baby plant. When the seedlings produce their first true leaves you can carefully take the seedlings out of the sand and plant them in the garden.
(Step 5) Water the seedling when needed, but never again disturb its roots or it will die. After three or four years your plant will flower. And then I can come and visit you. Wouldn't that be nice?
I enjoyed your Protea-seed planting story in PAN 4: 14. However, the seed coats of many Proteaceae species are hard in order to protect the seeds. The seeds of species that store the seeds on the plant (serotiny: as in Protea, Aulax and half of Leucadendron) will all germinate very well if planted as you said. But the seeds of those species buried by ants in their nests (myrmecochory) are very difficult to germinate.
I thought that you might want to grow some of these species from seeds: like pincushions, conebushes, pagodas, spiderheads, or scepters. Since it is now time to collect the seeds for your ant experiments. I thought you might like to collect some more so that you could plant them in your garden.
After you have peeled off the ant-fruit (you can use these in the ant experiments - will the ants come to the elaiosomes?) divide your seeds into two groups.
1) Plant the first group in sand about 30mm apart. Poke them in with your finer so that they are twice as deep as they are big. Mark the spot with a stick and label.
2) Take the other group and rub a tiny patch off the seed coat with sandpaper or a nail-file. Stop the moment you can see some white, as this is the embryo, or baby plant, which you do not want to hurt. Then plant them just like the first group, but in an area nearby. Mark the spot with a stick and label.
The best time to plant your seeds will be in March. Do not cover the seeds with a cloth: they will not blow away. But the cloth will prevent the sun from warming the soil, and the soil will not get cold at night. How then will the seeds know when to germinate? In nature the adult plants shade the soil from the sun and cold. Only after a fire has burnt up all the plants will the ground get hot and cold and hot and cold and hot and cold. That's when the seed coats know that it is time to let the seeds germinate.
Write in and tell us how many seeds germinated from each pile. Because the seed coat tells the seed when to germinate you should find that the seeds from the pile you sandpapered will germinate first. Also many of those not sandpapered will stay dormant (`asleep') until next year.
When your seedlings produce their first true leaves they will be ready to transplant into your garden.
Have a look at the Annual Botanical Society Plant Sale 1998 or Plant Sale / Garden Fair 1999 or Plant Sale / Garden Fair 2000 to see some of Phloeonomus' work in the preceding year or two or three or ?
Have a look at Stats on Seeds in Flowerheads.
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