494 BOTANICAL GAZETTE [DECEMBER 
form a fairly continuous row, but they gradually diminish in diame- 
ter and in number as they enter the late wood. They vary from 
0.04 to 0.09 mm., with an average of 0.076 mm. in diameter 
(table II). The veined segments are relatively short in this species, 
varying from 0.39 to 0.73 mm., with an average of 0.55 mm. in 
length (table III). Where two vessel segments join end to end the 
perforation is asinthe commonsycamore. Tracheids (pl. XXXIII, 
t) are variable in form, some closely resembling vessels and others 
very similar to wood fibers. Wood fibers (pl. X XXIII, wf) form 
the bulk of sycamore wood. The length of these elements in 
Arizona sycamore varies from 1.5 to 2 mm. in length, with an 
average of 1.7 mm. They are thick-walled and pitted as in the 
common sycamore. The wood parenchyma fibers and intermediate 
fibers of Arizona sycamore are similar in all respects to those of the 
other two species (fig. 2, A, B, C). Pith rays (pls. XXXII, 
XXXVI, pr) are conspicuous; the average of the large rays is 
0.16 mm. wide and about 12 times as high, and therefore much 
narrower and somewhat higher than in the common sycamore. 
The pith ray cells are round in the tangential section (pl. XXXVI, 
pr), and are usually much elongated radially. 
P. racemosa Nutt., California sycamore 
(pls. XXXIV, XXXVIT) 
Distribution.—California (from the lower Sacramento River 
through interior valleys and coast ranges) to Lower California (San 
Pedro Martir Mountain). 
Uses.—California sycamore wood, because of its limited supply, 
is used only locally and only to a small extent. It is somewhat 
lighter in weight and in color than the common sycamore, and is 
also less cross-grained and hence easier to work. Users of this wood 
claim that it is more durable and is also less liable to warp than the 
common sycamore. It should be useful for all purposes for which 
common sycamore is used except where great toughness is required, 
as in butchers’ blocks, ox yokes, wooden bowls, etc. It should be 
found useful especially for tobacco boxes, for which the wood of the 
eastern sycamore is so extensively used. 
