Help identify a plant?

Question

My little sister got into a plant in my grandparents' backyard, and we don't know what it is. Here are the facts:

-it has leaves that are uncharacteristically thick and juicy, like it might be a succulent

-it's not currently flowering (in Utah)

-The leaves are shaped sort of like teardrops that are pointy at both ends

-the stem is lighter green than the leaves

-the sap inside is milky white and syrup-ish

-the stem is about a foot long, and it lies along the ground like a weed

-the sap causes irritation to the skin and eyes

Answer 1

I would agree with milkweed except that milkweeds tend not to be creeping plants - they grow erect.

I'd think more of a member of the Euphorbia family.  See if any of these look like your plant:

http://plants.usda.gov/java/profile?symb...

http://plants.usda.gov/java/profile?symb...

http://plants.usda.gov/java/profile?symb...

http://plants.usda.gov/java/profile?symb...

ADDITION:  For the information of others, it should be noted that Euphorbia prostrata doesn't have leaves that are pointed at both ends - perhaps the person who suggested this species failed to read that part of your question.

Answer 2

sounds like milkweed.

its what monarch catipillers eat.

make it a good day

Answer 3

Without seeing a picture of the plant, it is hard to know for sure.  However, based on your description, my guess would be that it is Euphorbia prostrata (prostrate spurge).  It is a plant that is found in Utah and many other places around the country.  

Here is a link for more information about Euphorbia prostrata:

http://www.coopext.colostate.edu/4dmg/We...