Trees, Shrubs and Conifers: Anyone know how to tell the difference between..., 1 by Equilibrium

Equilibrium wrote:
Meant to add that I had found this from Xenomorf regarding P. microphylla-
http://davesgarden.com/guides/pf/go/76909/

Quoting: No thorns on the trunk, but the branch tips have them.
Green-yellow trunk, small leaves, irregular quasi growth structure.
Occasional deep watering for better foliage.
Provides just about the right amount of shade for some cacti.

A comparison between the flowers of five Palo Trees
--The Mexican Palo Verde (Parkinsonia aculeata), the upper petal starts out with red dots that eventually grow bigger and turn the entire top petal to red.
--The Palo Brea (Parkinsonia praecox), the upper petal has smaller & fewer red dots than the Mexican Palo Verde (P. aculeata) that don't grow bigger.
--The Blue Palo Verde (Parkinsonia florida), the upper petal is always a solid yellow just like the other four petals.
--The Little Leaf Palo Verde (parkinsonia microphylla), the upper petal is solid, all white, and the remaining petals are yellow.
--The Palo Brasil (Haematoxylum brasiletto), has flowers similar to Parkinsonia sp., and the top yellow petal has red dendritic streaks.

Here's the bark to the plant I found which appears to be P. aculeata-