Despite the pun, I’m not talking about marijuana here; springtime in Oregon is a period of lush growth across fields, lawns, and in the cracks of sidewalks everywhere. Ever wonder what those determined little plants are? Here are a couple of common favorites:
First we have Shepherd’s Purse (Capsella bursa-pastoris), a distinctive member of the mustard family that can be distinguished by its triangular fruits.
Supposedly, they resemble shepherd’s purses, but since I have never seen the purse of a shepherd, I imagine it looks more like a resting moth (with a really long tongue, if you include the peduncle). In any case, this plant is widespread throughout urban areas and can grow fairly tall if allowed. Otherwise, it is content to suck nutrients out of cracks in asphalt and grow less than a foot in height. Shepherd’s purse has small white flowers borne individually on long, thin peduncles from the main stem, each with four petals like most mustards (Brassicaceae). The moth-shaped siliques (that’s the fancy name for the fruit of a plant in the mustard family) mature from the bottom up, creating a cool gradient of dark to light to flowers at the end of the stalk.
Another of my favorites has a rather macabre common name: purple deadnettle (Lamium purpureum). Accordingly, this cosmopolitan weed has somewhat of an eerie appearance with its layered, shroud-like leaves which fade from green to a mysterious purple.
The plant is softly hairy all over, and the leaves grow opposite to one another and have conspicuous reticulate venation (they form a network across the surface of the leaf). The main stems are square in cross section.
If you look closely, you’ll find rather unique flowers peeking out from beneath the clusters of leaves. Similar to most flowers in the mint family (Lamiaceae), the petals are fused together to make somewhat of a tube shape with a bilaterally symmetric opening; there are two lobes at the top of the opening and two differently shaped ones at the bottom.
You’ll often find purple deadnettle growing in clusters on the edges of lawns or in abandoned lots. It likes to have some shade from the hot summer sun.
The last piece of today’s collage is actually a Pacific Northwest native: the humble pineapple weed. Named because of its pungent odor (seriously, crush the flower between your fingers and smell the tangy aroma!), the pineapple weed is unique among its relatives because its ray flowers do not produce the long petals we usually associate with the sunflower family (Asteraceae).
As you may or may not be aware, flowers of plant family Asteraceae are comprised of a whole lot of little tiny flowers clustered within the center of a ring of “ray flowers,” which produce the petals. In a daisy, for example, the ray flowers produce the white bits and the other flowers make up the yellow bumpy part in the middle. What’s special about the pineapple weed, then, is that its ray flowers do not produce these petals, giving it the appearance of a naked flower.
The leaves of the pineapple weed are dissected, meaning they appear thin and almost feathery. The plant doesn’t grow very tall–usually no higher than 6-8 inches. It’s rather adept at growing in hard or dry soil in my experience.
So there you have it: three weed species to look out for as you wait for the bus or take a stroll through a weedy vacant lot. It’s amazing what life you can find in the refuse!
The MereKat 