392 Groom. — On the leaves of L at hr aea Squamaria 
face near the margins differ markedly from the parts near 
the midrib in their possession of dome-like glands, more 
numerous capitate hairs, and in the close histological con- 
nexion of these with the fine ends of the bundles. 
Structure of the dome-shaped glands. These glands are 
built upon the same plan as those of Lathraea. Four cells 
with parallel lateral walls form a cap ; a large biconvex cell 
lies below ; and beneath it are four cells which, seen from 
above, look like the four quadrants of a disk, but have con- 
siderable round or elliptical intercellular space at the middle 
of each radius. The exposed walls of the gland are cuticu- 
larized everywhere save at the centre of the tip of the gland, 
where a pore like that of Lathraea occurs. The rim of the 
pore has a slightly thickened ring of cuticle, which often may 
be seen to project slightly outwards. A mucilaginous plug 
protrudes outwards in the form of a small hemisphere. In 
neither this plant nor in Pedicularis could I satisfy myself 
whether the plug is or is not perforated by an axial canal ; 
but in Rhinanthus the plug, looked at from above, often 
seemed to have the appearance of being traversed by a 
vertical fine canaliculus. The tracheides and vessels under- 
lying these glands are less developed and narrower than in 
Lathraea and Pedicularis , only near the leaf margin are the 
tracheides dilated. There is no cuticularization of the walls 
of the parenchymatous cells connecting the tracheides and 
the lowest series of gland-cells. The walls of the capitate 
hairs are externally cuticularized, there is no perforation of 
the cuticle. 
Odontites rubra. 
Rooted plants and cut shoots into which water was forced 
by mercury-pressure gave a very feeble excretion of water, 
even when kept in an atmosphere saturated with aqueous 
vapour. With the naked eye the drops could only be seen 
on the lower face of the leaf near the tip. My experiments 
with this plant were interrupted, consequently 1 can merely 
