Category Archives: Plants & Fungi

plants & fungi

Rabbit-foot Clover

Rabbit-foot clover (photo by Ivar Reidus via Wikimiedia Commons)

I never see rabbit-foot clover (Trifolium arvense) in Pittsburgh but it’s easy to find along the roadsides in Maine (where I happen to be).

Originally from Europe, it prefers dry sandy soil, field edges, and waste places.   This beautiful specimen was photographed in Estonia.

You can see how the flower got its name.

 

(photo by Ivar Reidus via Wikimedia Commons.  Click on the image to see the original.  This was a featured photo in August 2013.)

Even One Species Makes a Difference

Bumblebee (photo by Marcy Cunkelman)

In yesterday’s blog I mentioned the pesticide episode in Wilsonville, Oregon last June that killed 50,000 bumblebees.  This prompted me to wonder…

What would happen if just one species of wild bee completely disappeared from an area?

Computer models suggest that the remaining bees would take up the slack and none of the flowers would suffer.  Recent research shows this isn’t so.

Berry Brosi of Emory University and Heather Briggs of University of California Santa Cruz conducted a bumblebee study at the Rocky Mountain Biological Lab near Crested Butte, Colorado where native larkspur is visited by 10 of the 11 local bumblebee species.

They divided the wildflower meadows into 20 square meter plots.  In the manipulated plots, they used nets to capture and exclude just one bumblebee species.  In both the control and manipulated plots their team of Emory University undergraduates followed all the bumblebees everywhere, noting the flowers they visited.

Though bees are generalists they usually specialize in gathering nectar from particular species at the height of their blooming.  If you watch bumblebees on Joe Pyeweed in an August meadow you’ll notice they visit all the Joe Pyeweed in succession even though there are lots of other flowers to choose from. This benefits the flowers because the bees are wearing pollen from their own species.  The researchers confirmed this when they swabbed the bumblebees for pollen and analyzed the results.

In the control plots in Colorado, everything proceeded as expected.  78% of the bees focused on their favorite flower species. Larkspur seed production was normal.

Not so in the manipulated plots. With only one species missing, reduced competition for the flowers prompted the bumblebees to “play the field.”  Only 66% of the bumblebees focused on their favorite flowers.  The larkspur suffered, producing 1/3 less seed.

So the answer is:  If one wild bee species disappears some wildflowers will decline dramatically.

Everything’s connected to everything else.

Read more about the bumblebee study here in Science Daily.

 

(photo by Marcy Cunkelman)

p.s. No bumblebees were hurt during the study.  They were all captured and released.  Quite a feat!

Three Sumacs And Two Imposters

Sumac fruit (photo by Kate St. John)
Staghorn sumac: fruit is fuzzy (photo by Kate St. John)

3 September 2013

In July I took photos of sumacs along the Montour Trail but didn’t identify the species and assumed these first two were staghorn sumac.  Wrong!

As I started to write this article I examined the photos and noticed a big difference between them.  The red fruit spike above is fuzzy.  The one below is smooth.   Not only that, you can see that the stems on the top one are also fuzzy but the stems below are smooth.

Fruit of smooth sumac (photo by Kate St. John)
Smooth sumac: fruit is smooth (photo by Kate St. John)

In southwestern Pennsylvania we have three common sumac species that bear pointed red fruit clusters:

  • Staghorn sumac (Rhus typhina), at top, has fuzzy fruit and stems and is named “staghorn” because the fuzzy fruit spike resembles a stag’s horn in velvet.
  • Smooth sumac (Rhus glabra), above, is smooth just like its name.
  • Shining sumac (Rhus copallina) is easily identified by its winged stems.

I haven’t seen Shining Sumac lately so here’s a photo from Wikimedia Commons.  See how the stem has wings (like wingstem) between the leaflets?

Leaves and flower of Shining Sumac (photo from Wikimedia Commons)
Shining sumac (photo from Wikimedia Commons)

There are two more plants we call “sumac” whose leaves resemble these plants but they aren’t in the genus Rhus:

  • Poison-sumac (Toxicodendron vernix) is in the cashew family (as is Rhus) but it’s closely related to poison ivy and causes the same rash.  Its stems are smooth, like smooth sumac, but its flowers and fruit are not in dense spikes.  Fortunately poison sumac only grows in swamps and bogs so you’d have to go out of your way to touch it.  Click here for a photo.
  • And finally there’s a plant we call “sumac” which isn’t related at all.  Tree of Heaven (Ailanthus altissima) is an invasive tree from China with compound leaves that resemble sumac.  However its leaflets are notched, especially at the base, and the tree produces seeds instead of a fruit spike.  Notice the notches on the leaflets and the heavy cascade of seeds in this Wikimedia photo.   This is NOT sumac.   It grows anywhere, even in abandoned parking lots.
Ailanthus leaves and seeds (photo from Wikimedia Commons)
Ailanthus altissima with seeds (photo from Wikimedia Commons)

Three real Rhus sumacs and two imposters.

(photos by Kate St. John except where noted.  Click on the Wikimedia photos to see their originals)

Beauty Shot

Birdsfoot trefoil (photo from Wikimedia Commons)

Native to Europe, Birdsfoot trefoil (Lotus corniculatus) is blooming now in North America.  You can tell it doesn’t belong here because its bright yellow flowers seem out of place along the roads.

It’s a very pretty member of the Pea family with leaves shaped like birds’ feet.  Here you can see it looks like yellow crown vetch when you aren’t standing so close.

Fortunately in Pennsylvania it’s not as invasive as crown vetch, so I don’t feel bad displaying this beauty shot.

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

Now Blooming: White Wood Aster

White wood aster in Schenley Park (photo by Kate St. John)

If you wait long enough mysteries reveal themselves.

In April 2012 I displayed this photo of squawroot and asked readers the identity of the green leaf on the left side of the picture.  I thought it might be an invasive species.

Squawroot in Schenley Park, 2 April 2012 (photo by Kate St. John)

Mark Bowers and Loree Speedy answered it was probably White wood aster (Eurybia divaricata) which grows in large patches and therefore might look invasive, though it’s not.

Last week I finally put the lonely leaf and its flower together when I found the asters blooming in the same place where the leaves appear in the spring.

And yes it was in patches, small and large.  Small above, large below, in Schenley Park.

Patch of White wood aster in Schenley Park (photo by Kate St. John)

Mystery solved.   …Unless I was fooled again.

 

(photos by Kate St. John)

Makes Birds Red

Fruit of Amur honeysuckle (photo by Kate St. John)

Amur honeysuckle is invasive but it produces a lot of fruit for wildlife.

These bright red berries make northern cardinals quite red if they eat them while they’re molting — which they are doing right now.

Unfortunately honeysuckle fruit is not as nutritious as our native red berries, such as dogwood, so the birds look great but they don’t get as much fat and protein as they’d find in native fruit.

Seeds from the bird feeder can round out their diet.

(photo by Kate St. John)