The Frog Blog – Aquatic Weed Wednesday
Hello everyone and happy Wednesday! Today we will be talking about an aquatic plant that is not actually a plant but rather a macroalgae (algae large enough to be seen with the naked eye) c
alled Chara or sometimes, “stonewort” (Chara spp.).
There are many different species of Chara found throughout Ohio and the US and can be difficult to identify down to the species level. Because of this, we will focus on Chara from the genus level (i.e. Chara spp.). This macroalgae appears to have many structures that causes some people to misidentify it as an aquatic plant. It has stem-like structures, leaf-like structures, and some may even misidentify seed structures on it (which are actually male antheridium and female oogonium). Look for whorled branches around the stem with more condensed branching at the tip, similarly to coontail. Perhaps one of the best ways to identify chara is through your senses: when you crush the plant, it produces a “musky” smell and feels a bit sandy between your fingers.
Chara grows near the bottom of most ponds and lakes where sunlight is able to penetrate to the bottom. It prefers hard waters and the “sandy” texture mentioned above may derive from calcium carbonate crusts that grow on plants in these conditions. Additionally, the “musky” smell it produces when crushed sometimes cause people to give it the name “muskgrass”. Although Chara can become a nuisance in ponds and lakes, it rarely does so. In fact, some suggest that it improves water quality since it absorbs nutrients and stabilizes sediments without “topping out” to the surface. Because of this we usually suggest leaving Chara be in your pond unless you really want it gone.
By: Edward Kwietniewski
AQUA DOC Lake and Pond Management
Resources and External Links
Borman, Susan. Through The Looking Glass: a Field Guide to Aquatic Plants. Stevens Point, Wis. :Wisconsin Lakes Partnership, 1997. Print.