A dandelion with newly emerged florets. Photo by Robert Dryja
The seed head of a dandelion with hundreds of seeds ready to be blown away in a breeze. Photo by Robert Dryja
By ROBERT DRYJA
Los Alamos
Two kinds of plants are making their presence clearly visible since spring began six weeks ago.
Hundreds of dandelion plants have emerged in a grassy field. Each plant has up to 10 flowers called florets. The field first turned yellow with florets and then white with their seed heads. Each seed head has about a 100 to 150 seeds that look like little parachutes. The seeds now are drifting away by the thousands in the spring breezes. The field also is having the seeds from Siberian elm trees arrive by the hundreds.
They look like thin bits of yellow-brown paper. Patches of bare ground become coated with them. A dandelion and an elm tree could not look more different. The elm tree may grow seventy feet high while the dandelion may approach one foot. The elm tree has a trunk and branches covered with bark.
The dandelion is a cluster of green leaves close to the ground. But both are similar in that they are among the first plants to have flowers and release many seeds in the spring. This seed dispersal will end another week.
A third plant shows no sign of flowers, much less disbursing seeds. Nanking cherry bushes appear to have only fresh green leaves. However, a careful look along the bottom side of branches reveals green berries. The Nanking is keeping its seeds, opposite of what the dandelions or elm trees are doing.
Why are they growing this way? The answer is in the way they create, store and use nutrients during the summer growing season. All three kinds of plants create nutrients during the summer and store them over the winter. These nutrients then are immediately ready for growing flowers and seeds when spring arrives. Dandelion and elm tree seeds are small and are released early in the summer to be on their own. They will have four months for growth if they are among the fortunate few to land at a good location with soil nutrients. The Nanking cherry in contrast keeps its seeds for the summer. Its nutrients are used to grow large cherries.
The dandelion and Siberian elm grow thousands of small, light seeds so that a few may land in a good location for growth, courtesy of the wind. The Nanking cherry in comparison grows a relatively few heavy seeds. Birds later in the summer may eat and drop the now bright red berry seeds at a good location to grow. The large seed of the Nanking cherry provides nutrient to the young plant that is inside of it. Nanking cherry seeds that are released later in the summer can wait until next spring to start growing since they have nutrients stored within them. Dandelion and Siberian elm seeds need to start growing immediately since they have no stored nutrients.
Imagine these plants as parents who are answering several questions. Should I use my nutrients to grow many small children? Or should I grow a few large children? Should my children be sent on their way soon? Or should I keep my children until they are more grown up? Should I keep nutrients mostly within myself? Or should I give my children nutrients to keep for themselves?
The seeds from a Siberian Elm tree lay on the ground, ready to sprout. Photo by Robert Dryja
The seeds of a Nanking cherry bush remain on a branch, storing and growing with the nutrition provided by the parent plant. Photo by Robert Dryja