Tracheid length was determined in macerations and in tangential sections of cores from three <i>P. longaeva</i>, age 500, 600, and greater than 2200 years. In the oldest stem, tracheid length has steadily increased with age and is continuing to increase. The younger stems indicate that the juvenile phase of steep increase in tracheid length lasts several centuries. The wood anatomy of <i>P. longaeva</i> is described and found to be very similar to that of <i>P. aristata</i>. Both species differ in minor details from the related <i>P. balfouriana</i>. -- AATA