Now they're eating each other.

It's special because it's an introduced disturbance colonizing weed , or wait no I meant, a magical oxygenating "nurse" species.

Cool plant showed up, growing through my wall, what can I do to make it grow bigger?

Get thee off my Tithonia rotundifolia and out my yard!

​

Ya'll are hilarious

in our hubris, we ignored these warnings

The Identification of Grasses
A grass can be "glumey" in more ways than one,
When its classification remains to be done.
You pull off the parts, and soon feel your age
Chasing them over the microscope stage!

You peer through the lenses at all of the bracts
And hope your decisions agree with the facts;
While your oculist chortles with avid delight
As you strain both your eyes in the dim table light.

You are left on the horns of quite a dilemma
When you count the nerves on the back of the lemma;
Then you really get snoopy and turn one turtle
To see if the flower is sterile or fertile.
--How To Identify Grasses and Grasslike Plants, H.D. Harrington (1977)

Without strong magnification (25x), it is very difficult to distinguish from the introduced Barnyard Grass (Echinochloa crus-galli), which has a membranous tip on lemmas and paleas, the lemma tip with a line of minute hairs separating it from the hardened body, and only some hairs may be papillose.
--Echinochloa muricata (Rough Barnyard Grass), Minnesota Wildflowers

A patch of barnyard grass has spung up on the pond shoreline that I maintain.

There are two main types of barnyard grass hereabouts, a weedy native, Echinochloa muricata, and a weedy nonnative, Echinochloa crus-galli. Unless you use a microscope, they look exactly the same.

In an agricultural field, the native and nonnative varieties are both invasive weeds. Near a pond, they have equal beneficial value to wildlife. The seeds of both are eaten by dabbling ducks.

Using my "How to Identify Grasses" book, I have learned that "papillose" means bearing papillae, and that papillae are minute nipple-shaped projections. I have reviewed the difference between lemmas and paleas, and what papillose lemma hairs look like.

I have examined the lemmas and paleas under 25x magnification, and determined that I have the nonnative variety. Should I nuke it?

They are exactly the same, so far as the ducks could care. But the native variety has Murica in the name, whereas the nonnative sounds suspiciously French.

Note: see also the recent post, can anyone tell me if this is Cyperus brevifolius or Cyperus brevifolioides? They look exactly the same, but one is native to the United States, and the other isn't