Most varieties of Eryngium are perennial - maybe some slug or other chewed through the base of the stem and thats why it came away in your hand. Assuming the basal leaves are still present, the plant should still be alive, and should produce more stems next year, but if those leaves are shrivelled, and you only planted it this year, maybe its been short of water with this heat?

Vine weevil are prolific this year and they will attack all sorts. Check around the rootball if there is no growth at the soil level.

Thanks both...it was a variagated "soft" one, I was quite surprised when I felt it because it looked really prickly,I bought it from a show garden at Gardeners World last year, it did ok last year, but I was told they don't like to be at the back of a boarder by an "expert"at the garden club so I moved it in march to the front.It grew to over a foot tall,then just keeled over.....no sign of ANYTHING at the base,so I guess thats it....just wondering do they get prickly with age?

No, not really, Poppylinda - any idea what the varietal name was of the one you bought? Most eryngium produce a tap root, so you may find it pops up again next year, but some are not long lived.

Didnt have a ticket Bamboo,dont like prickly plants so was surprised when I felt it, did notice in the "plant tent "there were different varieties strangely hadnt seen one before perhaps because they are a bit temperamental and dont age well.

Some are annuals, Poppylinda... fingers crossed yours pops up again.