Northland Nature: Burdock burrs inspired Velcro invention

Aug. 18—We may notice the ripening of berries and fruits, including apples, hazelnuts and acorns, as the season moves on at this time in August. Despite the fact that the summer has been dry (several inches less than normal rainfall), many plants are still growing quite well in the region.

Recently, while driving locally, I saw the tall grasses of the roadsides and fields. Also in the fields was the cutting and baling of hay. But there were many other plants to be seen here, too. Late summer is the time of goldenrods and I have been finding more in bloom each day. We have about a dozen kinds that typically grow here. They may be just a couple feet tall or more than 8 feet; nearly all are yellow. And with this consistency, goldenrod species can be hard to discern.

In addition to the florals, recognition needs good looks at the leaves. I have noted nine so far. Though common in the open, they are not alone. Here too are sunflowers. This group, which includes black-eyed Susans and coneflowers, is also comprised of about a dozen kinds, some quite tall. Nearly all are yellow.

Also yellow, common and about 3-4 feet tall, are the sow thistles. Not true thistles, they have "dandelion-like" flowers and seeds. And there is the ubiquitous tansy. Many roadsides are filled with these plants and their smelly leaves and yellow flowers.

Yellows are numerous, but whites can be seen too. I saw plenty of flat-top asters. About 3-4 feet tall, they had huge flat white flowers. In the wetland, bonesets abound with abundant tiny white flowers, also in a flat arrangement (umbel). At the lakeshore were the three white petals of arrowheads while out in the water white water-lilies flourished despite the shrinking water level.

Purple flowers were seen among the large-flowered asters, often taking over disturbed sites. Tall bull thistles were still holding purple flowers above their spines. In swamps, I saw the delightful Joe Pye weed with plenty of size and color. But at one site, where I pulled off the road, I was greeted by a huge plant with lots of strange looking ball-shape flowers.

The plant was taller than I am and among its many leaves and branches, it held lots of burs. Above these hooked and bristly bracts were roundish-shaped stalked flowers. These burs, more than three-quarter-inch in diameter, were growing in clusters. At the top of them was the florets, lavender in color. The plant was robust with lower leaves looking something like that of rhubarb.

This big plant, burdock, is one that many of us know better by its bur growths than the flowers. These growths hold the seeds that develop later in the season. With spines and hooks, they readily attach to our clothing and hair. (The

invention of Velcro

was inspired by these burs.) Uninvited by us, we remove these burs and discard; just what the plant wants since this is its way of dispersing the seeds.

This robust growth is the mature plant, two years old, since it is a biennial. At the end of the first season, it is merely a flat leafy rosette with no flowers. Leaves, thick stems, flowers and burs all appear with the plant's maturity in the second year.

We will likely see this plant again later this season after the seeds have developed to become the sticky burs that we are familiar with, but now we can see it flowering.