Friday, November 29, 2013
Imagine that every person in the world had all of his or her natural life compressed into a single year, from start to finish. Talk about intense! That’s what it is like for the plants that we call “annual” species…those that germinate from seed, then grow as much as they can from a (usually) rather fibrous root system, finally going into reproductive “mode” and producing a crop of seeds, before drying up and withering away. Many of the garden favorites around us, such as cosmos, zinnia, and marigold, are annuals. The evolution of an annual life term in plants is a bit risky, because there is only one period of time (a single growing season) available to get everything done. For an annual plant, the overriding “goal” in existence is the formation of as large a crop of viable seeds as possible, these representing the next generation, and an untimely drought, flood, fire, or insect attack may ruin the seed crop. Now, plants that live for a number of seasons--the perennial species--have something of a luxury in not needing to be in such a rush. For them, if one particular growing season is not conducive to abundant seed production, that’s OK: maybe the next year will be better. After all, a perennial plant will keep growing season after season, coming back repeatedly from a rhizome or bulb, or something similarly massive below (or above) the ground, so it will have plenty of chances to reproduce. Annuals only get one shot.
This is a native annual species, common over much of eastern North America. It is usually smooth and dark green, with plenty of toothy leaves, these sometimes lobed, up and down the stem. Healthy, happy plants growing in optimum settings may be nearly 6’ tall, but they can bloom when they are much shorter. The plants produce plenty of seeds when they finally start flowering, from mid-summer until frost. (Another attribute of annual plant species is that they produce a relatively high number of seeds, usually equipped with some mechanism for being dispersed widely, thus increasing the likelihood of their being established the next season.)
It’s a member of the sunflower family (Asteraceae), and thus it has lots of small flowers congested into heads. The individual heads are green and barrel-shaped, wrapped around on the outside by a layer of slender bracts. Each flower ultimately produces a slender, brown nutlet (or “achene”), equipped with a prominent fluff of a snowy-white pappus. So, once the plant starts doing its thing, it will shed hundreds –thousands?—of little white parachutes, each one with a nutlet, containing the seed.
It turns out that this is a very efficient way of moving around. This species commonly shows up in places that have been disturbed, even slightly. Scraped places in the deep woods, including wind-caused tree throws (“tip-up” mounds) are a good place for it. It is even more likely to occur wherever there has been burning, whether small-scale campfire sites, or in extensive settings of previous forest fires.
Answer: “Fireweed,” Erechtites hieracifolius]
John Nelson is the curator of the A. C. Moore Herbarium at the University of South Carolina, in the Department of Biological Sciences, Columbia SC 29208. As a public service, the Herbarium offers free plant identifications. For more information, visit www.herbarium.org or call 803-777-8196, or email firstname.lastname@example.org.