HEW PHYTOIiOGIST. 
Vol. XI, No. i. 
January, 1912. 
[Published February 5th.] 
RAY TRACHEIDS IN SEQUOIA SEMPER VIRENS. 
By Marjorie Gordon. 
[Text-Figs. 1—7]. 
NTIL recently it was thought that ray tracheitis were absent 
from the genus Sequoia. Speaking of this genus Mayr in 
1890 says: “ die Markstrahlen bestehen durchaus aus Parenchym- 
zellen ” (p. 271). In 1903, Jeffrey, in his special monograph on the 
Sequoias, makes no mention of ray tracheitis. Gothan, in 1905, 
discovered ray tracheitis in 5. gigantea —“ bei welcher species 
iibrigens in altem Holz auch hier und da Ouertracheiden vorkom- 
men ” (p. 848). Two years after Gothan’s discovery, Penhallow, in 
the description of the genus in his text-book on the North American 
Gymnosperms (1907) states that the rays of the Sequoias are with¬ 
out tracheitis (p. 223). Later, Jeffrey, in his article on Cunning- 
Jiainia sinensis (1908) speaks of the finding of ray tracheitis by 
Gothan in S. gigantea anti adds that they “ have not yet been found 
in S. senipervirens ” (p. 598). 
The material for this investigation was from a museum specimen 
of the wood of S. senipervirens. From its external features it could 
not be seen whether it came from near the pith or from the outer 
part of the stem. The microscopic character of the annual ring, 
however, shows it to have been from an old portion of a stem : the 
annual rings are flat, and there is very little indication of a 
“ middle ” layer—a feature in which, as Gothan has shown, old stem 
and root-wood often agree (see Fig. 7). In this wood both marginal 
and interspersed ray tracheids were found. 
The marginal ray tracheids are different in shape from the 
central parenchymatous ray cells. Fig. 1 shows a radially elongated 
ray tracheid which extends along the ray for a distance equal to the 
width of two-and-a-half spring tracheids, is about half as high as a 
central cell, and has a very irregular free margin. Often these 
