Tracheids in the Node of Equisetum maximum. 129 
Fig. 15. Stratiotes. A transverse section through the root near the apex. 
Fig. 16. Limnocharis. A longitudinal section through a young root. 
Fig. 17. Limnocharis. A longitudinal section through a somewhat older root. 
Fig. 18. Limnocharis. A longitudinal section through a fairly old root. 
Fig. 19. Limnocharis. A transverse section through a root some distance 
from the apex. 
EXPLANATION OF THE LETTERING. 
pi., plerome. pb., periblem. cal., root-cap. ed., endodermis. pr., pericycle. 
d., dermatogen. ct., cortex. 
NOTES FROM THE CAMBRIDGE BOTANY SCHOOL. 
II.—TRACHEIDS IN THE NODAL REGION OF 
EQUISETUM MAXIMUM . 
By M. G. Sykes, 
Girton College, Cambridge. 
[Text-Fig 26, 1—5.] 
W HEN cutting transverse sections through a node of Equisetum 
maximum in order to observe the indications of secondary 
thickening noted by Cormac, 1 some very curious large reticulately 
pitted tracheids were observed in the lumen of a carinal canal just 
below the nodal region. 
Cormac pointed out that, in view of Strasburger’s 2 statement 
that water is conveyed through the lumen of the carinal canals, 
and as these canals are not continuous from one internode to the 
next, some elements must be provided to convey the water from 
one canal to another at the node. He suggested that the expla¬ 
nation of the proliferation of tracheids at the node (by secondary 
thickening), might lie in the necessity for such provision. 
It seems probable that the peculiarly large elements shown in 
the accompanying figures may have some special connection with 
the transport of water between the canals of adjacent internodes. 
In transverse sections, a little distance above the node a few 
reticulately pitted elements are seen on either side of the vascular 
bundle; as the sections approach the node these elements increase 
in number and size and begin to project into the carinal canal 
(Text-Fig. 26, 1 and 2). The canal is soon filled up by them ; at the 
point of entrance of the leaf-trace, which is also the region of forking 
1 Cormac. Annals of Botany, Vol. VII., 1893, p. 63. 
2 Strasburger, Leitungsbahnen, pp. 435-438. 
