1915] CHRYSLER—RAYS OF CEDRUS 303 
From a number of the observations here recorded the inference 
seems unavoidable that marginal cells in the genus Cedrus are in 
a vanishing condition. Such observations are: the scattered 
occurrence of marginal cells, varying from an almost continuous 
Tow to occasional cells; persistence of the erect cells of the phloem 
in line with a few scattering marginal cells on the xylem portion 
of a ray; the tapering or tailed shape of the cells; occurrence of 
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Fic. 6.—C. libani, stem; part of the fifth and sixth growth rings, showing earlier 
appearance of ray tracheids than parenchyma; X 290. 
crystal-bearing cells in place of tracheids or starch-bearing paren- 
chyma; occurrence of shadowy cells or “ghosts”; the capricious 
occurrence of marginal tracheids, as pointed out by STRASBURGER. 
If then the marginal cells are disappearing, Cedrus would appear 
to show reduction from some such genus as Pinus or Picea. The 
foliage of Cedrus suggests a relation to Pinus, while the cone bears 
more resemblance to that of Adies. The relation to Pinus is 
further indicated by the observation of Jerrrey (2) that when 
traumatic resin canals are induced in Cedrus they occur in both 
