RIO MATO EXPLORATIONS OF HOWARD SCOTT GENTRY 
MEXICO 
OF ABBBEVIATJOHS fm 
Rio on th# l«btl as it follows spec if Ic place 
nanies Indicates tt«t th» locality Is In th® Rio 
Mayo water shod. Selected becai:»e it orients tlim 
localities gec^aphleally sad scolds ambiguity of 
names* 
Bio Fuertet Rio Fuerte water shsdj as for Rio May# 
Canyon Karc Issue t originates In tfe© east slope of Sierra 
da la Ventana and dlsobargeB Into the Rio Mayo at 
Caramechl. 
Canyon Salltreros originates in the east slope of Sierra 
de la Ventana and dlBcharges into the Rio May© at 
Caramechi. 
Tepopat a rancho on the Rio Mayo elope of Sierra Chiril^* 
On the labels they may be treated as ajnonjm, for 
all Sierra Chlribo collecting was done at Tepops. 
Canyon* Indicates generally the narrow upper stretches 
of a water course, the surea of origin* 
Arroyo* Indicates the lower protitM* of a water course^ 
the sides of which are not closely confined by hill 
sides or high cliffs. 
Tropical "sonorwi I Tropical Sonoran Life Sons, which may 
be regarded as a S’abdivlslon of the Lower Sonoripi 
Life Zone, or as a zone of equal rank* I have used 
this term in place of the loosely used and such abused 
Semltroplcal Life Zone. Observations Indicate tbo Rl© 
Mayo is a rough northern limit for the Tropical 
Sonoran Life Zone* Occupies elevation from sea level 
to three thousai^ feet T. 
Lower Sonoran* Lower Sonoran Life Zor^, distinguished 
fron the Tropical Sonoran Life Zone by lees rain^ 
fall and a sparser flora* occupies elevation from 
sea level to three thousaM fe^ ?. 
Upper Sonoran* Upoer Sonoran Life Zom. Lies at a higher 
elevation than the two preceding Zones, three thousand 
