22 University of California Puhlications. [botany 



It was first called to our attention by Professor Jepson, who has 

 also noticed it in pines bordering certain meadows in the High 

 Sierras. 



The variety Jeffreyi is here -treated with the true P. ponderosa, 

 for the reason that they usually occur togetlier, and the differ- 

 ence is sometimes so slight that it is impossible to distinguish 

 them with certainty. Mature specimens of P. ponderosa are 

 characterised by their large size, by their bark, which is in large 

 plates, the deep-green foliage and the small cones, Init young or 

 half- grown specimens are very much like those of the variety. 

 At the lower edge of the belt only the species occurs, in the 

 great Yellow Pine belt of the middle altitudes we find them 

 growing together, while along the upper limits of its range only 

 the variety is found. 



Incense Cedar {Lihocedrus decurrens) . — The Cedar was 

 found to be well distributed throughout the Lower Transition 

 Zone, but being always scattered among other trees it nowhere 

 becomes an important element in the forest formation. It 

 requii'es more moisture than the Yellow Pine and is therefore 

 restricted to the larger valleys and to the vicinity of streams, 

 along one of which it was found descending to an altitude of 

 8500 feet. On the north side it runs down to the ,4000-foot 

 contour and on the east to 6000 feet, near the lower edge of the 

 Transition Zone. It extends to near the upper limits of this 

 zone in Tahquitz Valley, where it was seen growing at 8000 feet 

 altitude. 



Sugar Pine {Pinns Lamheriiana) . — This pine begins at 

 about 5000 feet altitude and extends from that contour nearly 

 throughout the Transition Zone. It is very common and of 

 large size along the trail that skirts the western side at about 

 6000 feet, but is less common both above and below that alti- 

 tude, while on the southwest side of the Tahquitz-Strawbeny 

 Divide the Sugar Pine is the most abundant tree; but it is rarely 

 met with in Tahquitz and Round Valleys, except on rocky slopes, 

 which it seems to prefer. It is its frequent occurrence along the 

 two principal trails, perhajis, that has led some to over-estimate 

 the amount of Sugar Pine on the mountain. 



On the high ridges that run out from Tahquitz Peak the trees 



