Wednesday, April 6, 2016

Smooth Rockcress

Smooth Rockcress - Mark Bower
We celebrate the arrival of spring in many ways - the arrival of Harbinger of Spring, the first butterfly, the first show of redbuds.  Then small white flowers appear on the serviceberry, the preview of the main act, the flowering of our Missouri State Tree, the dogwood.

"Our" Smooth Rockcress - REK
Spring comes on in much smaller acts as well, discovered before most plants and shrubs cover them up with leaves.  We found rather inconspicuous dark green leaves of Smooth Rockcress, Boechera laevigata, on a moist rock seep along the base of a bluff, nurtured by a dense mat of moss.  The tiny gaping jaws of leaves on the right exposed flower buds, waiting to make their appearance in a month or so.  In the shade of the rocks I couldn't photograph the buds but the next day Mark Bower sent me a beautiful set of pictures of Smooth Rockcress that he had found.

B. laevigata is a biennial, meaning that it has a two year life cycle similar to thistle, teasel and garlic mustard.  The first year its energy goes into growing vegetative structure, its roots, leaves and very little stem, staying close to the ground.  The second year the stem "bolts," the stalk shooting up where it flowers and produces seeds.

Rockcress buds patiently waiting - Mark Bower
Growing on moss covered rock - Mark Bower
Even tiny plants have their faunal associations.  The tiny flowers are pollinated by equally tiny bees including Andrena arabis (Rock Cress Andrenid Bee).  The leaves are hosts to the beautiful Falcate Orangetip butterflies we have been seeing the last few weeks.  They will be laying their eggs and then dying off as their caterpillars develop over several weeks, then form a chrysalis in May that they will survive in until next spring.  Although this sounds like a risky lifestyle, it obviously works for them.

from Minnesota Wildflowers





We will be monitoring the little rockcress during the late spring when it will typically bloom.  The flowers last for 1-2 months but are hard to see, the white petals barely extend beyond the green sepals, all less than a third of an inch long.  We have flagged the area to be sure to find them.

* The life of the Orangetip Falcate is the subject of this 2015 blog.

Nibbled down- Mark Bower
Addendum:  Mark was following the plant to get a picture of its flowers, but a herbivore beat him to it overnight.  There isn't a lot to eat right now on the hillside so it is understandable.  Squirrels are reduced to crawling out on branch tips to nibble on tree buds while dangling precariously.  This plant lost its chance to procreate so I will have to guard ours carefully.
"This Buds for me  -  REK."  - 

1 comment:

  1. Spring is the best season of the year, the renewal of everything and the fresh air including allergies. lol

    Adorable squirrel capture. =0)

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