Erigeron compositus seed heads

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RickR
Title: Moderator
Joined: 2009-09-21
Erigeron compositus seed heads

From this photo John Weiser posted on Image of the day, I asked him what the remnant seed heads are that peak up from the bottom of the pic. He said they were Erigeron compositus.

I lamented how mine don't look nice at all:

Being a coincidence of lazy man, I still hadn't removed the old remnant seed heads, and yesterday morning after raining all night, I woke up to this - the DEAD bracts had lifted to a horizontal position!

And now today, after drying out, they are back to their down turned state.

Is this normal for the genus? And John, had you taken that original pic after wet conditions?

Hoy
Hoy's picture
Title: Member
Joined: 2009-12-15

Rick, they re hygroscopic. Dead plant cells often react on moisture in the air. It has been used here as a kind of weather forecasting device:

First picture (from http://no.wikipedia.org/wiki/Gimmestad_gamle_kirke): An old cod (350 years) forecasting the weather. The plant fibres in the rope absorb moisture and turn the fish according to the weather.

Second picture (from http://www.yr.no/nyheter/1.6721514) A "weather twig". The twig absorbs moisture and points upwards or downwards. When pointing down it means dry, sunny weather and no rain (if it is mounted the way it sat on the tree).

Trond
Rogaland, Norway - with cool, often rainy summers  (29C max) and mild, often rainy winters (180 cm/year)!

RickR
Title: Moderator
Joined: 2009-09-21

Trond, I have seen that weather stick sold here in the U.S.  Any idea what species it is?

Rick Rodich    zone 4a.    Annual precipitation ~24 inches
near Minneapolis, Minnesota, USA

Hoy
Hoy's picture
Title: Member
Joined: 2009-12-15

RickR wrote:

Trond, I have seen that weather stick sold here in the U.S.  Any idea what species it is?

Yes, spruce is the better but pine is OK too. When my father told me about it he used spruce (Picea abies - but the species doesn't matter I think). I believe he also used the small, old, suppressed trees from the understorey.

Do you want to start a new business?

Trond
Rogaland, Norway - with cool, often rainy summers  (29C max) and mild, often rainy winters (180 cm/year)!

RickR
Title: Moderator
Joined: 2009-09-21

Hoy wrote:

Do you want to start a new business?

;D No.  This is all very interesting to me.  So where these spruce are native, do you see the old dead branches on the trees raising and lowering with drastic humidity changes while still attached?

The old man who made my snowshoes 30 years ago told me the better ones had a frame made of spruce wood, because once steamed and shaped, they hold their shape.  This in contrast to ones made of ash, for instance, that need to stored correctly to keep their upturned tips from flattening out.  That doesn't sound very plausible, considering the weather stick phenomenon.  He was a Slovenian immigrant, but I don't know where or when he learned to make snowshoes.    Maybe our North American spruce are different?

Rick Rodich    zone 4a.    Annual precipitation ~24 inches
near Minneapolis, Minnesota, USA

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