Number 528

I just added species number 528 to my list of plants found growing at Blue Jay Barrens.  Smooth Rock Cress, Arabis laevigata, was found growing in the bare, rocky soil along the woodland edge.  This member of the mustard family isn’t very showy, but it is a native.  It’s always a treat to find a new plant growing here, especially a native.

The plant was about 18 inches tall, but the thin stalk and few leaves made it hard to see.  A careful search of the surrounding area revealed no more of these plants, so for now, this is the only individual know to be on the property.  I’ll keep watching for more.

It’s easy to see why the plant is referred to as smooth.  Stalk and leaves are completely free of any hair or other irregularities.  Projections at the base of the leaves reach out to hug the stalk.  I’m always pleased when plants have features that can be detected without using any special instruments.

There were three stalks growing on this plant.  One was already producing several fruits.  The long seed pods, known as siliques, arched out and then curled back toward the plant stalk.  This shot gives a good idea of the steepness of the ground where the plant is growing.  The camera was level.  It’s the plant that was leaning, along with the ground.

This is the part of the plant that confuses me.  Smooth Rock Cress is supposed to be a biennial.  Basal leaves should grow the first year, followed by a flower stalk the second year.  After flowering, the plant should die.  This plant seems to be growing from a rhizome that is also producing new clusters of basal leaves.  It seems logical to expect those clusters of basal leaves to produce flower stalks next year.  The flower stalks can die back each year, but the plant lives on as the overwintering rhizome.  I’m thinking that the plant I’ve found is actually a perennial. 

I’ll have to add this plant to my watch list to see if it does come back next year with more flower stalks.  I’m betting it will.  Some Arabis species are described as being biennial or perennial.  Descriptions of Smooth Winter Cress don’t mention the option of perenniality, but it might be possible.