254 RECORD: STRUCTURE OF CERTAIN WOODS 
allel lines, often of very regular length and arrangement, while 
separating the tiers is a fine line of lighter or darker shade than 
the remainder of the wood. These lines are made by the junctions 
of the tiers of wood cells and vary in appearance according to the 
elements involved in a particular area, whether fibers with inter- 
lacing tips or vessel segments and wood parenchyma cells with 
abrupt terminations. In some instances, also, the local aggre- 
gations of pits in the fiber walls where the lumina become con- 
stricted tend to increase the refraction there and make the lines 
more distinct. According to Von Héhnel (1, p. 33) this is very 
pronounced in Bocoa provacensis Aubl. (Inocarpus edulis Forst.); 
his findings are confirmed by Wiesner (5, pp. 15, 950), who figures 
the pits. In the cases investigated by the present writer such 
pit-areas were noted in several woods, as for example, in Machae- 
rium, Physocalymma(?), and Erythrina. 
Where the rays are all storied they occupy the median portion 
of each tier, the height of which is usually considerably greater 
than the height of the rays. Consequently there is room for 
considerable variation in the height of the rays without interrupt- 
ing the regularity of the transverse markings. It is not uncom- 
mon to find some of the rays grown together at the margins and 
thus occupying two or three stories, as for example, in Cercis, 
Crescentia, Ormosia and Ougenia. Where the rays are in perfect 
seriation, a section between two tiers misses them completely. 
In most instances, however, such a section shows rayless gaps, the 
width of which depends upon the regularity of stories. 
In some storied woods, especially in the Bombacaceae, Mal- 
vaceae and Sterculiaceae, the rays are of two general sorts, large 
and small. Here only the low rays are in seriation and they may 
be so few, comparatively, and so over-shadowed by the large 
rays that the ‘‘ripple marks”’ are indistinct except in proper light 
and may be easily overlooked in casual inspection. In some of 
these woods the markings may be plainer without the lens than 
with it and, because of the very limited field under observation, 
may not be distinguishable at all under the compound microscope. 
In both of these types the elements other than the rays are 
normally storied. The vessel segments and vascular tracheids 
correspond in length to the height of each tier, though occasional 
