This plant I just can't figure out. Lately (as of June), I've been seeing it on the side of the road a lot, especially in more desolate areas. As you can see, the smaller parts of the leaf are not quite the typical design of the plant. The underside of the leaf has little transparent pricklers. The plants grow in relatively large clusters, and as of yet, I've noticed most stems reach a height of 2 to 2.5 feet minimum. I've also noticed that the plants seem to grow well in partial shade to full sunlight, or so it seems. Moreover, a closeup of the leaf reveals veins travelling from the base of the leaf stem to equally subdivided areas of the sub-leaves in a up-down fashion. I just saw this a while back and was totally freaked out by it.
I don't think you need worry. It looks a lot like a Ricinus communis You can read about it here too: Ricinus communis (Castor Bean, Wonder Tree)
My castor beans don't look like this nor do they have picklers on them. Mine are red and have a smooth, palmate leaf. right now they are small but by the end of summer they stand around 7' tall.
I think there are lots of different types of Ricinus. I did a photo search and there are many shades of green and red leaves. The only way to be certain is to wait for the blooms and fruits I guess.
Hard to tell from the photo, but it looks almost like a young leaf of the Hogweed plant that grows here Heracleum mantegazzianum (Giant Hogweed) You mentioned that it has 'pricklers' on the underside of the leaves. How about the stalks? Does it have spots of red or purple and pricklers up the stalk? Have a careful look at the photos in the link and if it matches be very, VERY careful. This plant can cause serious health problems. edited to add that Hogweed is on the list of Texas Invasive Plants http://www.texasinvasives.org/plant_database/detail.php?symbol=HEMA17
