what is the opposite of contractile?

totototo@telus.net totototo@telus.net
Thu, 20 Sep 2007 09:12:32 PDT
On 19 Sep 07, at 9:46, Max Withers wrote:

> There is an interesting discussion on the mediterranean plants list
> about bulbs that that seem to push themselves out of the soil,
> occasioned by Drimia (Urginea) maritima:
> http://hort.net/lists/medit-plants/…
> Anyone have any theories about why some bulbs do this (some of the S.
> African Amaryllids also come to mind)? Someone pointed out that just
> because a plant can do something does not necessarily mean there is an
> adaptive reason to do it.

You don't have to go that far to find an example. Galanthus nivalis 
often pushes bulbs to the surface, and I've even seen Narcissus 
cultivars do the same. The physical mechanism seems to be overly 
exuberant production of offsets until crowding forces some onto the 

The adaptive value is that doing so facilitates asexual reproduction.

Commercial bulbs of /Iris danfordiae/ are notorious for breaking up 
into "rice grains" unless planted very deeply. My guess is that this 
too is a strategy for facilitating asexual reproduction when the 
bulbs are near the soil surface.


"It's MY computer, Mr Gates. Stop trying to tell me what it will/won't do."

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