
124 THE AMERICAN NATURALIST. | [Vor. XXXIX. 
C. speciosa (Figs. 3, 7). 
Transverse. — Growth rings narrow, rather uniform, consisting of about 
one half spring and one half summer wood distinguished by their variations 
in (1) size of cells, (2) the thickness of the walls, and (3) the disposition of 
the cells. Cells of the spring wood large, thin-walled, hexagonal or some- 
times tangentially extended, in somewhat obvious radial rows; those of the 
summer wood hexagonal, uniform, thick-walled, smaller and 07 at all in 
radial rows. Wood parenchyma dark and resinous, the cells forming tan- 
gential and concentric series at frequent intervals, chiefly in the summer 
wood. Wood tracheids thin-walled, few, in two or three rows terminating 
the growth ring as a layer of uniform thickness. Vessels of the earliest 
spring wood at first very large, oval or round, rarely compounded, and 
chiefly devoid of thyloses ; quickly reduced and soon compounded in radial 
and tangential series and finally reduced to about twice the diameter of the 
wood cells; very numerous throughout the growth ring to which they 
impart an element of great porosity. Medullary rays somewhat numerous, 
dark, 1-several cells wide, distant upwards of 445 y. 
Radial. — Wood parenchyma abundant, the cells in parallel rows, 14.6 p 
to 100 y wide; sparingly resinous, the radial walls with rather numerous, 
small and simple pits. Medullary rays sparingly resinous; the cells chiefly 
uniform in height except the marginal ones which are very variable, short 
in the summer wood and upwards of 24 times the height, or in the spring 
wood several times longer than high, the upper and lower walls sinuately 
unequal, rather thick, conspicuously pitted; the. terminal walls straight, 
strongly but rather finely pitted; the lateral walls devoid of pits. except 
opposite vessels where they commonly show a fine sieve-plate structure 
or are otherwise numerously pitted. Vessels chiefly rather short but very 
variable, the terminal walls rather thick but not pitted ; the radial walls with 
‚multiseriate, very variable, hexagonal, round, oval, transversely oval or 
oblong, often much elongated and distant pits, the orifice finally becoming 
a much elongated, narrow slit without a border, thus showing transitions 
into scalariform structure. Radial walls of the spring wood cells with 
rather small, longitudinally oblong pits in vertical series. Tracheids of the 
summer wood interspersed with wood parenchyma, the radial walls spiral 
and scalariform and merging into rather small, oval, bordered pits upwards 
of 5-seriate. 
Tangential.— Medullary rays numerous, low to very high, often equal 
to 2 mm., dark, resinous, one to unequally multiseriate and upwards of 5 cells 
wide; the cells small, round or oval, thick-walled, variable, the terminal 
cells commonly oblong. Wood parenchyma of the spring wood composed 
of short cylindrical cells with square or fusiform ends, the tangential walls 
with numerous, multiseriate but small, transversely oval, bordered pits. 
Tangential walls of the vessels with numerous small, multiseriate, hexago- 
nal or transversely oval, bordered pits. 
