1917] BRUSH—SYCAMORE WOODS 489 
except toward the outer boundary of each year’s growth, where 
they become very much shorter (pl. XXXVIII, pr). The cross- 
walls between the ray cells are sometimes vertical, but more often 
they are slightly oblique. 
Analytical key 
Pith rays 0.22-0.34 mm. wide (average 0.29 mm. or 14 cells); 
average height, 1.36 mm. or 50 cells; average ratio of width to 
height, 5.—P. occidentalis (pls. XXXII, XXXV, XXXVIII). 
Pith rays 0.10-0.22 mm. wide (average 0.16 mm. or 8 cells); 
average height, 1.84 mm. or 84 cells; average ratio to height, 12.— 
P. Wrightii (pls. XX XIII, XXXVI). 
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Fic. 3.—Radial view of portion of pith ray of P. racemosa: a, individual paren- 
chyma cells; bp, bordered pits; c, crystal; 200. 
Pith rays 0.04-0.20 mm. wide (average 0.09 mm. or 5 cells); 
average height, 2.36 mm. or 107 cells; average ratio of width to 
height, 26.—P. racemosa (pls. XXXIV, XXXVII). 
Individual characteristics 
P. occidentalis L., common sycamore 
(pls. XXXII, XXXV, XXXVIIT) 
Distribution—Southeastern New Hampshire and southern 
Maine to northern Vermont and Lake Ontario (Don River, near 
north shores of the lake); west to eastern Nebraska and Kansas, 
and south to northern Florida, central Alabama and Mississippi, 
and Texas (Brazos River and thence south to Devils River). 
Uses.—Common sycamore is used to a large extent for plug 
tobacco boxes, furniture, butchers’ blocks, ox yokes, wooden bowls, 
and cooperage, blind wood in cabinet work, chairs, refrigerators, 
