Monday, December 21, 2009

Purple Triple-Awn

Noticing differences allows you to discover new components of an ecosystem. The golden-brown patch of grass in the middle of a predominately reddish-brown landscape indicates the presence of an unusual type of grass. In this case, the unusual grass is a rarity known as Purple Triple-awn, Aristida purpurascens.

This grass has a thin stem and extremely narrow leaves. When in a clump, the result looks like a wad of Easter grass supporting a mass of long pins. Once you’ve seen it, it becomes an easy species to pick out.

The flower spikes always look a bit scraggly. This specimen has lost very few of its seeds and is typical of what will be found at the time of seed maturity.

The long, thin projections are the awns. Each floret bears a set of three awns, hence the name Triple-awn. Nature programs like to show a species of grass that has the seed planted by a corkscrew motion of the awns. I haven’t seen that action with this species, but the awns do support the seed so one end is held away from the soil surface. This may make it more likely for the seed to fall into a crack formed by the frost heaving of soil during the winter.

I’ve been picking some of the seed and scattering it around this immediate area. I’m now seeing Purple Triple-awn 50 feet away from the original cluster I found about ten years ago. Next I’ll try moving the grass to some other locations in this same field.

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