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12-02-2003, 02:26 PM

In article , ose (Sean Houtman) wrote:
From: (Phred)

But if we're talking *dispersal* then that's another matter, and I'm
not sure what help the awns would be in that sense -- except perhaps
mechanical entangling in hair, fur, or feathers. (But I can say that
the seeds of black spear grass [_Heteropogon contortus_] don't need
the *awns* to become painfully embedded in your flesh! The hairs on
the tip of the "seed" seem to do the job quite well enough if they've
got a bit of purchase on something like your socks. And some of the
three-awn spear grasses [_Aristida_ spp.] are worse! )

If you would like to see how awns can help disperse seed without tangling in
fur, get a spike of wheat or barley (use one of the awned varieties of course),
and let it roll across your hand. The awns pretty much make sure that the spike
tends to move in one direction.

Yes, I can remember as a child playing with one of the native grasses
that we called "caterpillar grass" because when you put the
inflorescence (in this case) on you hand and stroked it gently, it
"walked" across your hand.

So I take your point. I guess it's a matter of scale -- I was
thinking of "dispersal" in terms of metres or more rather than
centimetres.

Cheers, Phred.

--
LID