78 Muhlenbergia, Volume 8 



bark of yowng Jeffrey i -ax^ in striking contrast to the bright or 

 apple-green leaves and rough brown bark of ponderosa of equal 

 age. 



Pinus ponderosa was discovered May 12, 1826, in the vicin- 

 ity of Spokane, Washington, by David Douglas. It is widely 

 distributed, according to Sudworth, "occurring in every State 

 west of the Great Plains and one hundredth meridian," and is 

 also found in northern Mexico proper as well as Lower Califor- 

 nia. If P. scopiilorum of the Rocky mountains, which he in- 

 cludes in this range is excluded, the statement must be modi- 

 fied. 



Pinus Jeffreyi^?iS first collected October 24, 1852, in Shasta 

 valley, or more probably on the edge of Shasta valley, in north- 

 ern California, by John Jeffrey. The northern limit of the spe- 

 cies is Douglas county, Oregon, according to Jepson, Silva 81, 

 and is found as far south as Mt. San Pedro Martir, Lower Cal- 

 ifornia. It is also the chief timber tree of western Nevada as it 

 is found in greatest abundance on the eastern slope of the Sierra 

 Nevada. 



Since this paper is but preliminary to an exhaustive study 

 of the two species as they occur in Nevada, I shall merely point 

 out the chief differences, and with the accompanying illustra- 

 tions it should not be difficult to distinguish them. Some per- 

 sons claim that y^^^jz merges \nto ponderosa^ but I think this 

 is not the case. WhWe Je/freyi \s the predominant tree in west- 

 ern '^Qvads.^ ponderosa is more or less -mixed witli it. The bark 

 of mature trunks is, of course, somewhat variable, but there is 

 enough sameness in the members of the one species to distin- 

 guish them from the other. Even the smallest cones oi Jeffrey i\ 

 but little larger than the maximum ones oi ponderosa, are easily 

 separated by the broader, rather thinner scale with a slender, 

 usually downcurved prickle. The seeds are nearly twice larger, 

 much more mottled, and are of a different shape. I'he two spe- 

 cies are much alike in habit and l.iave leaves of about equal size, 

 and this is about all that they do have in common. 



