Sporobolus contractus

Spike Dropseed

Field view of Sporobolus contractus, common name Spike Dropseed.

The narrow spikes are usually 9 to 12 inches long (can be less or more).

Spike Dropseed is spike-like, not a true spike.

There is a tuft of hairs at the joint of sheath and leaf (also along sheath margin). Other narrow-spiked Arizona grasses don't have this.

Spike Dropseed leaves are long. But the top leaf blade just below the seedhead is often only about 6 inches long and extends out at a right angle (next view, top left).

Sporobolus contractus spkes are thin and long, commonly 9 to 12 inches long by 1/8 to 1/4 inch wide.

Here is a closer view of the texture of the inflorescence.

Spike Dropseed is a condensed panicle rather than a true spike: it has short, appressed branches.

Roots of Spike Dropseed.

How to Identify Spike Dropseed

  Sporobolus contractus, a perennial bunchgrass, grows medium high, usually hip high. The seedhead can be 6 to 18 inches long, usually somewhere in between. It occurs in every county except Greenlee and La Paz. The key is to find the long, thin spike, then the hair-tuft at leaf base. There are no awns. The glumes are very unequal in length.

Similar Species

  There are two close look-alikes in Arizona; both are species of "muhly," Muhlenbergia. They are of similar size and shape but neither has Spike Dropseed's hair tufts at leaf base and along the sheath margin. Muhlenbergia rigens (Deergrass) seedheads are sometimes gently curved instead of straight like Spike Dropseed. Muhlenbergia longiligula (Longtongue Muhly) has an exceedingly long ligule, the white or translucent little "tongue" at the junction of sheath and blade. Neither of the other look-alikes have this long ligule.