Questions about seeds from hot and dry summer areas

Jane McGary
Wed, 18 Jun 2003 09:31:51 PDT
John Lonsdale asked,

>Can anyone please tell me whether seeds which are dispersed from geophytes
>which are native to areas which are hot and dry in the summer (and therefore
>summer dormant) will get dry in the summer?  The obvious answer to this
>would be seem to be yes - so I am asking myself why I continue to water pots
>of such seeds during the summer.

They would get VERY dry if they just lay on the open ground, of course, but 
many Western American geophytes seem to disperse their seed (e.g., by 
"tumbleweed" inflorescences) so that it will blow into crevices, where 
presumably the seed would sift down and be somewhat protected from drying 
as well as from seed-eating birds and animals. Also, some seeds probably 
get covered by drying grass and other foliage and in a sense mulched. I 
think ants carry a lot of them off underground, where they eat 
non-reproductive structures of the seed and it then germinates (this is 
especially noticeable in Trillium ovatum).

Josef Halda once told me that pots of Eremurus seed, which take 2 or more 
years to germinate, should not be watered in summer. I have also withheld 
summer water from some xeric Chilean seeds. I do this by putting them in 
the dry portion of the bulb frame or somewhere else with dormant bulbs that 
I don't water.

I do think a lot of Mediterranean-cycle seeds germinate better if stored 
dry at room temperature from the time they are harvested until they are 
planted in fall.

Jane McGary
Northwestern Oregon

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