On my way to somewhere else on the Internet I found…

Rubber rabbitbrush (Ericameria nauseosa) is a shrubby perennial in the Aster family native to the arid American West.  It’s a hardy plant that thrives in poor conditions, sending down deep roots even in coarse and alkaline soil. I’m sure I’ve seen it in Nevada but it wasn’t blooming at the time.

For most of the year rubber rabbitbrush — also called chamisa or gray rabbitbrush — looks a lot like sagebrush but in the late summer and fall it produces clusters of pungent-smelling yellow flowers that light up the landscape.  Pungent is probably a kind word for the smell.  Some compare it to the smell of a wet armpit.  Bees like it, though.

Its odd name comes from …

• The sap which contains rubber. It was studied as an alternate source of rubber during World War II.  The idea didn’t catch on.
• “Rabbitbrush” is forage for deer and antelope but rabbits don’t eat it.  Maybe rabbits hide under it.
• The word “nausea” sticks to this plant’s scientific name even after it changed from Chrysothamnus nauseosus to Ericameria nauseosa.  Nauseosa might describe its smell.

But what really caught my eye was the fact that in one valley in New Mexico these plants are radioactive.

As mentioned above, rubber rabbitbrush will grow in poor soil and send down deep roots.  In Bajo Valley near Los Alamos there’s an old nuclear waste dump.   Years after the area closed, rubber rabbitbrush grows above it and those particular shrubs are radioactive.

According to Wikipedia, “Their roots reach into a closed nuclear waste treatment area, mistaking strontium [strontium-90] for calcium due to its similar chemical properties.  The radioactive shrubs are “indistinguishable from other shrubs without a Geiger counter.”

This happens to humans too.  Our bodies mistake strontium for calcium and put it in our bones.  It’s good news when treating osteoporosis with non-radioactive strontium but bad news if your water contains radioactive strontium from industrial, mining or Marcellus shale drilling waste.

When in doubt, test your water.

But don’t worry about radioactive bushes.  You’d have to go to Bajo Valley, New Mexico to find them.

(photo from Wikimedia Commons.  Click on the caption to see the original.)

Here’s another flower that blooms in the fall.

Bottle Gentian or Closed Gentian (Gentiana andrewsii) is found in moist meadows in the southern half of Pennsylvania.  I usually find it near the lake at Moraine State Park. This one is from Marcy Cunkelman’s garden last month.

The flower is fascinating because it’s closed so tightly that small insects can’t get inside.  Only bumblebees can force their way in to sip the nectar.

Occasionally an insect will bypass the closed tips by drilling straight into the base of the flower.  Alas.  This mars its intense blue petals.

(photo by Marcy Cunkelman)

We often think of orchids as rare tropical plants that grow on trees.  Did you know we have quite a selection of them in Pennsylvania? 

The Botanical Society of Western Pennsylvania‘s Wildflowers of Pennsylvania illustrates 37 species in our state.  But don’t look for them in the trees.  Our orchids are terrestrial.

One of them is Nodding Ladies’ Tresses (Spiranthes cernua) and it’s blooming right now.  According to Wildflowers of Pennsylvania, “Nodding Ladies’ Tresses is usually found as colonies in marshy fields, wet meadows and ditches throughout Pennsylvania.”  

Dianne and Bob Machesney found this one at Moraine State Park last Sunday.  “We found 57, in groups of one, two or three, along a half mile trail in a strip mined area, reclaimed with pines.”

The photo above is a close-up of the flower spike; the whole plant is shown below.

Look for Pennsylvania’s orchids and you’ll find gems close to home.

(photos by Dianne Machesney)

8 October 2011

October is a good time of year to see wood glow in the dark. The phenomenon is called foxfire and is most often caused by the honey mushroom (Armillaria mellea), native to eastern North America.

Armillaria mellea feeds primarily on hardwood and is most often noticed when it produces fruit –> honey mushrooms.  The mushrooms are like the apples on a tree.  There’s a big plant structure that produces the fruit, but in the case of Armillaria you can’t see the “plant” until it glows.

The glowing comes from its rhizomorphs that look like long, black bootlaces and grow under the bark of dead trees, downed logs, old roots and stumps.  They also grow on living trees which they eventually kill.

The faster they grow, the more they glow because their feeding process produces light.  Their bioluminescence is a chemical reaction that’s the opposite of photosynthesis.  The tree they’re consuming used CO₂ + light to produce organic (carbon-based) material + oxygen.  The fungi use luciferin molecules to combine organic material + oxygen to produce CO₂ + light.  Pretty ingenious, eh?

Finding foxfire is problematic, especially for city folks like me.  The light is a faint green or blue glow that’s easily swamped by man-made light.

The habitat and weather must cooperate too.  The infected wood has to be damp — not too wet, never dry — and the best temperature is 77^oF though anything above freezing is acceptable.  Summer heat (86^oF+) shuts down bioluminescence which makes autumn, with its early sunsets and cooler temperatures, an optimal time to see it.

I’ve never seen foxfire but that’s no surprise.  I’d have to drive to a very dark place (how far?) and wander in the woods at night looking for a faint glow, hoping I don’t encounter a mammal I don’t want to meet.  Spooky!

Have you seen foxfire?  Where?

(photo of foxfire in Allegany State Park, New York by highlatitude on Flikr, Creative Commons license.  Click on the photo to see the original)

Last month Dianne Machesney found beautiful flowers blooming at Cape May, New Jersey.  This one is Maryland Meadow Beauty (Rhexia mariana), a wetland plant that likes sandy soil.

Rhexia mariana grows as far north as Michigan and Massachusetts but neither of us have seen it in southwestern Pennsylvania.

I’m sure that’s because our area has the wrong habitat … few wetlands and almost no sand.

(photo by Dianne Machesney)