CONIFERALES 



225 



specimen, 30 cm. in height and 25 mm. in diameter, was 98 years old, 

 so that the width of an average growth-ring was only 132 microns, 

 or about seven growth-rings to the milHmeter. In this region there 

 is just as extreme dwarfing of Tsuga heterophylla and Thuja plicata 



Fig. 239. — Taxodium mucronatum: the "Big Tree of Tule," about 15 miles south of 

 Oaxaca, Mexico. 



(gigantea). These dwarf trees have much the same appearance as 

 the famous Japanese dwarf conifers. One of these trees, in a single 

 year in a favorable location, produces as wide a zone of wood as the 

 dwarf produces in 50, or in nearly 100, years. Thuja plicata has been 

 known to reach a diameter of nearly 4 meters. On the neighboring 

 San Juan Island, in Puget Sound, Pteris aquilina reaches a height 



