September Visit (9/29/2016) 2 of 3

It’s oak gall season!  I spotted the leaf below right in the middle of the trail, with galls from two different wasps.  The urchin gall wasp (Antron quercusechinus) makes the spiny pink galls and the crystalline gall wasp (Andricus crystallinus) makes the furry pink galls.  These wasps, in the family Cynipidae, lay their eggs in oak leaves (in this case a blue oak), and the eggs secrete plant hormone mimics which cause the leave to form the spectacular gall.  The larvae grow and feed in the gall for weeks to years, depending on environmental conditions, and then pupate within the gall and emerge as adults.

oakgalls_2016sep29_sm

Continuing the oak theme, I looked carefully at oak regrowth along Cold Creek.  Interior live oak, an evergreen oak, is generally a more vigorous basal sprouter, as observed below:

liveoakgrowth_2016sep29_sm

Blue oaks, which are deciduous, generally do not resprout from their bases, but show regrowth in their crowns:

blueoakgrowth_2016sep29_sm

One thought on “September Visit (9/29/2016) 2 of 3”

  1. These are lovely! I wish I could make a habit of sketching (especially nature sketching), but that’s one habit I just haven’t nailed down. Hmm…I see a New Year’s Resolution in the making.

    Like

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