Muhlenbergia porteri

Bush Muhly

A dry bush of Muhlenbergia porteri, common name Bush Muhly.

Another Bush Muhly.

You can see the best field mark: long branches, one-inch leaves, and Dots on Threads within the branches.

Bunches of branches and short leaves can partly conceal the inflorescences of spikelets.

Muhlenbergia porteri shows its delicate seedheads.

The branches are bent at the nodes, sometimes one node per inch, with the short leaf blade sticking out.

Use the 1/4-inch grid to see the size of these tiny elongate spikelets.

And here you see the quarter inch awns, sometimes gently curved but not sharply bent.

Each tiny spikelet has two short glumes half as long as the floret (visible on lower left).

How to Identify Bush Muhly

  First notice the dots on threads. Then that the tiny "dots" are elongate and awned. Then that the awns are about 1/4 inch average (not 1/2 inch). Then that the glumes are only half as long as the florets (the floret minus the awn)--you will need your hand lens for this. Finally, the plant looks bushy and there are wiry stems (culms) with many sharp bends that hold short, 1 or 2 inch, leaves. These stems and leaves grow right through the dotted inflorescences, making them look messy.

Similar Species

  The very similar Purple Muhly (Muhlengergia rigida) has awns about 1/2 inch long. Other "dots on threads" have no awns or very short ones about a millimeter long. Purple Muhly occurs only in 4 southeast Arizona counties (COCH GRE PIM SAN). Many Muhlys have "dots on threads," but other than Bush Muhly only Purple Muhly has awns. So if you see the elongate, awned "seeds," the 1/4 inch awns, the short glumes, and the other attributes above, you can safely identify Bush Muhly.
  Watch out for the much larger but similar spikelets ("seeds") of Achnatherum species (now called Eriocoma) and the bunched seeds of Piptatheropsis. Both of these have long glumes that cover the floret inside.