S. mexicana is found growing from southern Texas in the United States south through much of dry Central America. It is a single trunked fan palm whose trunk can reach heights of 50 feet in habitat w/a diameter of up to 1 foot in diameter.
I can't tell you where or when I obtained this palm. But it is happy here. I planted three in a triangle about 5 feet apart w/a Syagrus sancona in the middle. Here is what the four palms looked like in 1998.
Six and a half years later they are looking good the Syagrus is sticking out above the Sabals.