Scutellaria resinosa

Last Tuesday I was giving my students a tour through Bartholdi Park and was a bit stumped by this plant.  The square stems and the bilaterally symmetrical flowers are good clues it is in the mint (or Lamiaceae) family, but what genus?

 

Luckily, I was able to email someone at the USBG and send them the shot.  A few hours later I got the answer -- Scutellaria resinosa or prairie skullcap.  Scutellaria means saucer or shield shaped and refers to the larger lower petals of the flowers.  These lower petals are designed to aid in seed dispersal, particularly during rain.  When petals are struck by rain drops, they catapult seeds off the plant. This makes beautiful sense for a plant that is native to dry prairie grasslands: the seeds only leave the plant when it rains, which is when they have the greatest chance of germinating.

There are differing explanations for the name skullcap -- some say the white markings on the petals resemble a skull (seems like a stretch to me); the other explanation attributes the saucer shape of the petals as looking like the bone we call the skullcap.