rgr18] RECORD—RESINOUS TRACHEIDS 65 
PENHALLOw states that no exact comparison can be established 
with other plants. The writer believes that exact parallels exist 
in many of the angiosperms. A good example is Nyssa sylvatica, 
and figs. 4 and 5 show resin-like plates (RP/) in this wood which 
exhibit virtually the same origin, form, and distribution as those 
Fic, 4.—Transverse section of Nyssa sylvatica 
in Pinus albicaulis. In Nyssa these masses occur in both the tra- 
cheae and wood prosenchyma and have their origin in the vertical 
strands of wood parenchyma (WP) and in the rays (R). Globules 
(a, 6) are shown emerging from the pits. The plates across the 
vessels are thin (c), but those in the libriform fibers may be very 
thick (d); in fact much of the fiber cavity may be completely 
