- Storied or tier-like structure of certain dicotyledonous woods* 
SAMUEL J. RECORD 
A considerable number of dicotyledonous woods are character- 
ized by a storied or tier-like arrangement of their secondary ele- 
ments. Such woods exhibit on longitudinal section, typically on 
the tangential, fine transverse lines, bands or striations commonly 
called “ripple marks.’’ These markings may be distinct to the 
unaided eye, may be at or near the limit of vision, or may require 
the lens. In some cases they may be more readily seen without 
the lens than with it, or they may be fairly distinct under the lens 
but indistinct or apparently absent under the compound micro- 
scope. In specimens with very dark and infiltrated heartwood 
the markings may be obscured there but show plainly in the sap- 
wood; usually, though, they appear to best advantage in the heart- 
wood. 
In woods with this type of structure the cambial cells are 
in tangential as well as radial seriation and part or all of the 
elements to which they give rise preserve this arrangement. Or- 
dinarily it is only in stems of considerable thickness that the tiers 
assume a marked regularity, but the diameter a stem must attain 
before the storied structure becomes pronounced is subject to 
wide variation, depending not only on the species but also on the 
rate of growth. In certain stems of Leguminosae and Zygophyl- 
laceae the tiers were found to be fairly regular in what was appar- 
ently the second annual ring, less than one eighth inch from the 
pith. In general, though, this feature is wanting in the twigs of 
herbarium material. 
The storied structure may not extend to all of the elements. 
In the extreme and also the most common form (Zygophyllaceae, 
Bignoniaceae, Leguminosae in large part, and others) the rays, 
vessel segments, tracheids, wood fibers, and wood parenchyma 
strands are all in horizontal seriation. On the tangential surface 
the cross sections of the rays appear as short, closely spaced, par- 
* Contribution from the Yale School of Forestry, No. 4. 
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