Can anyone ID these plants from the Yucatan Peninsula in Mexico?

Question

http://www.ruthtimme.com/Mexico/pages/page_110.html
http://www.ruthtimme.com/Mexico/pages/page_112.html
http://www.ruthtimme.com/Mexico/pages/page_109.html

Many Thanks!

Answer 1

The first is a caltrop of some kind, probably big caltrop. The second is American sea rocket. Both of these are cosmopolitan weeds of sandy places.
The third looks like something in the Crassulaceae, like a jade plant (Crassula) or stonecrop (Sedum), but I don't see any stamens. The only dioecious genus is Rhodiola, which isn't a good match. So it might actually be in the Rutaceae, but I didn't see anything I liked.
But 2 out of 3 ain't bad.