Southern Naiad: another native plant

Southern Naiad: another native plant

By Priscilla Hollingsworth

I was leaning over the boardwalk last week, and I spotted a plant in the main Butler Creek stream that I had not seen there before. Clearly it was attached to the bottom and had long, wavy green stalks and leaves that rippled in the current. It’s really kind of pretty. I was wondering, what is this plant?

Southern Naiad in flowing water

Various Phinizy Center staff helped me figure it out.  I showed photos on my camera to Aaliyah Ross and Jen McGruter in Education, and they began flipping through books in their library.  Jen grabbed a D-net, and we went back to the boardwalk, where she used the net to fish out some of the plant.

Southern Naiad close-up

You can see it has long, slender stems and very skinny leaves.  The leaves on the tips of the stalks round out into spatulate forms.  Jen really had to tug to get some of the plant to break away from the bottom, so it is pretty strongly rooted.

Southern Naiad branching habit

Jen examined the branching structure of the leaves.  Here, the leaves appear to branch off in pairs along a given stem.

Then we trekked over to the Research building, and asked Nate Hobbs what he thought.  He directed us back to a very small book in the Education office, where we found an entry on Southern Naiad, or Najas guadalupensis, which is a native species to our area.  Ruth Mead came in just then and confirmed we had found the right plant.

I felt like I had taken up too much of everyone’s time, but Jen assured me that this had been useful – now they had an identification on another native plant found right in Phinizy Swamp.

Here’s what I learned about Southern Naiad.  It’s found over most of North and South America, in fresh waterways such as lakes, ponds, streams, and canals.  The plant can grow up to about 10 feet long – it may need to if the waterway is that deep, since it’s rooted to the bottom and the leaves need to reach the sunlight near the surface for photosynthesis.  There are about 40 naiad species worldwide.  The leaves are quite narrow and grow in opposite pairs or in whorls of three.  The leaves have little teeth shapes on the margins, but you will need magnification to see the teeth on some varieties of the plant.  You’ll also need magnification to see the flowers – they are tiny.

Southern Naiad is an annual.  It spreads easily by seed or by bits of the plant breaking off and rooting elsewhere.  In some situations, it is considered a weed because it grows so fast and can take over the space in a pond or stream.  However, you can’t argue that it’s taken over at the Phinizy Swamp boardwalk – it’s clearly not overabundant relative to everything else growing nearby.  Southern Naiad is a primary food for turtles and waterfowl.  Macroinvertebrates (tiny water animals that are just large enough to see with the naked eye) find shelter in this plant.

Finally, the way the long green strands ripple in the water kind of reminded me of mermaid hair.  That’s a good association with the plant’s name.  Naiads were female water spirits in ancient Greek mythology.