I found a "yerba anise" also known as Mexican mint marigold and Tagetes
lucida.  My book (Southern Herb Growing) by Hill states it is a
compositae  perennial, blooming gold in the fall and reaching a height
of 2 - 3 feet, evergreen in all but the harshest winters.  Leaves are
used for tea as well as green salads.

Another book (A Modern Herbal by Grieve) lists "yerba santa" , habitat
Nothern Mexico and California with bluish flowers, taste is balsamic
and sweetish, afterwards acrid, but not bitter.  It is a 2 - 4 foot
high shrubby evergreen plant.

Same book also mentions "yerba reuma",  habitat is California, Nevada,
Arizona and Northern Mexico.  It has a salty taste, no odour, and has
an astringent aftertaste.  It is a small plant and grows in sandy
places.

Same book again mentions "yerba dulce" or Mexican Lippia, said to cause
amoung many other things, drowiness.  It is also known as "Lippia
Graveolens in Mexico.  The active ingrediant is Lippiol.  It is an
evergreen shrub about 18 feet tall, having many small yellow flowers.

Good luck figuring out this herbal mystery.
Carla