Zuzu, this is a Google-Chile search for the species:
If the one Sue posted, or the one of the second row in Goodle-images were of the species, wouldn't it have to be either
A. pelegrina var. rosea or A. pelegrina ssp. rosea?
All the pictures you will find with the species name show definitively the one and only Alstroemeria pelegrina there is, with very characteristic petal shapes and colour (except for the one in fluor photoshop) and very characteristic leaves-disposal. I have heard there rarely occurs an A. pelegrina var. alba, but have never seen it - I haven't found picures either.
The one Sue posted and the one from the seller/nursery in Ca. whom I wrote today as well MIGHT have some A. pelegrina genes in its hybridization, but that makes it a hybrid and not a variety of the species.