Saturday, July 10, 2010

Round Podded St. Johnswort

Last week I mentioned the non-native Common St. Johnswort . There are also some natives like this Round-podded St. Johnswort, Hypericum sphaerocarpum, a short growing plant with a vibrant lemon-lime colored bloom. I’m always happy to see this plant.

No dark spots mark these velvety petals. The mass of long stamens tend to stay bunched together until the time of peak pollen set and then they spread out to create an illusion of softness. Spread stamens seem to signal insects that this flower is ready for visitation. I call this little bee a Calf Pincher, because this type always gets on the backs of my legs when I wear shorts and gives me a little pinchy sting when I crouch down.

Once the flower is fertilized, the stamens tend to close back together. The old petals persist for quite a long time after pollination. Their shriveled remains are often still present when the seed filled pod reaches its full size. The sharply pointed bracts seem to stand as a guard around the developing bloom.

Dangling from beneath a flower is not a normal position for a bee. So what could be holding that bee in place?

I was guessing Ambush Bug, but instead, I found this nice chunky crab spider. Many species of crab spiders ambush prey that has come to feed at a flower.

Small bees are probably the most common prey for these spiders. Later in the summer, it often appears that the majority of flowers have crab spiders stalking their petals. It’s the high numbers of flower visitors that makes it at all safe for small insects to search for nectar and pollen. The spiders can only eat so much each day, so the loss of a couple of insects makes it safe for the majority of visitors.


  1. Fascinating post once again. I enjoy visiting your blog.

  2. Now let me get this right it better to get out later in the day to collect pollen...if I where a calf pinching bee.... hoping that the spider has already eating his fill or what??? ; }
    Sorry about that just rambling : }!! It is amazing the things that go on in nature that if where are not observant we never notice...thanks for being observant and blogging what you see!!!

  3. Thanks, Lois.

    grammie g - I seem to recall an old saying, "The calf pinching bee drinks nectar at three." That means I can safely crouch down at 3:00, because the calf pinching bee will be at the flowers where the already stuffed spider is sound asleep. Aren't we lucky there's an old saying for every situation?

  4. We have a Hypericum down here known (accurately) as "stickleaf." The flowers are small, yellow, of the same design as yours--the leaves look velvety, but feel just a little rough. And they adhere flat to clothing. If you try to brush them off, they "melt" (like an iron-on patch) onto your pants-leg (the usual spot to find them.) If you put the jeans in the washer, you'll have a leaf-shaped green decal on your jeans through several more washes. If you very VERY gently and slowly peel them away, you might get one off whole.

    We have crab spiders on wild flowers early in spring--as soon as there are flowers, crab spiders inhabit them. Then the ambush bugs join the hunt, and in late summer and fall the lynx spiders. I love the way the camera reveals details I can't see--or at least wouldn't notice--with the naked eye.

  5. Elizabeth - Our Hypericum are more behaved than that, but we do have a tick trefoil that does a similar trick with its fruits each fall.

    I'm always finding details in photos that I never noticed in the field. When I shoot a lot of close up shots, I usually take a landscape shot just in case I have to find that spot again. It's not unusual for me to head back into the field to check some detail I had overlooked. I never go out without my camera.