Four of the five crab apple trees
There is a row of 5 ornamental crabs at the edge of the apartment parking lot overlooking the pond. They bloom pink and white, and then shower the ground with snowy petals. In the early Fall, they all bear dense clusters of fruit. Two of them have red fruit that are about 3/4 inch in diameter and three have fruits that are a little more orange and a bit bigger.
Yesterday, while waiting for a friend to pick me up for a great buffet brunch at Nalapak , I looked more closely at the line of trees that I enjoy so much. I knew they were two different varieties, the three and the two, but more traits than the color of flowers and color and size of fruits distinguish them from each other. Here is one type:And here is the other:
Why would the fruits look so remarkably different on the two ornamental crab apple trees? A while ago, as a part of the Master Naturalists' program, I helped out with an inventory of the Arboretum at Lake Harriet. There is a men's garden club in Minneapolis that donated dozens and dozens of varieties of crab apple trees to the garden, and while we are all the beneficiaries of their generosity in the Spring, as are the cedar waxwings in the Fall, the City didn't keep very good records of what was planted where. One of the chores for the project was to try to decipher what varieties were represented and where the were located.
Like most things that are in front of us on a regular basis, we look at them, but we do not see. When I have taken something for granted in this way, I try to teach myself how to look at the subject afresh. In the case of the crab apples, I had to learn what the variables were. Bark, branching patterns, flower color, bloom onset, bloom length, petal shape, anther color, bracket variations, fruit shape, fruit color, disease resistance, crown shape, and other distinguishing traits exist. What I saw demonstrated during my casual Sunday morning examination of these trees was persistence. That is, how long the fruits remain on the tree. The fruits of the first tree shown are still unwrinkled round, and very clearly still on the tree. I wonder if the pit is larger or smaller? The fruits of the second tree are shriveled and sparse, probably taken by birds, since I see none on the ground (although other critters might have scavenged them from the ground).
All of this makes me wonder why the genome of the ornamental crab contains all these possibilities. Genetic manipulation can force expression of traits, but most of those traits already lie waiting as potentialities within the species (I'm just not going to consider spliced-in traits for now). In the case of these two trees, I imagine that the withered fruit didn't require cold to tenderize the flesh and make it palatable to birds, so they were taken earlier. The other fruit probably requires some harsh treatment before the flesh is soft enough to ingest and nourish. These fruits may persist on the tree until the same migrating birds that ate the fruit from the less persistent trees come back from their wintering ground, pass through this feeding area and take the older fruit. The trees benefit because their seed will be spread both South and North at seasonally favorable times, and the birds benefit because there is a variety of food available when they need it. Ideally, persistent and non-persistent fruits will exist on the same tree, but if not, the knowledgeable gardener/arborist will plant both persistent and non-persistent fruiting trees for the birds.
So this is the kind of think I think about while I'm cooking, or knitting, or my mind is taking a short wander in the middle of writing a contract. Realizing how everything fits together so well makes my heart glad.
Monday, November 24, 2008
Four of the five crab apple trees