muddyknees2000 said:

The walking tree seeds was just EU nonsense.....in McQuarrie's painting they are clearly arachnids or spider-like animals of some sort.

While I agree it does 'sound' like EU stuff... IMO McQuarrie's painting heavily suggests a relationship beteen the spiders and the trees, one is white, one is brown but they are the same shape, same size, same texture (Especially the knobly abdomen).

Plus it seems to be laying eggs/seeds around and beneath the trees. I wonder if anybody working on Aliens had this painting in the back of their minds when they made the Queen's egg sack?

Another painting...