Tabor.—-The Leaf Buds of Archytaea alternifolia . 1017 
base of the outer leaf, and showing very distinctly the teeth with which 
the margin is beset. 
These teeth occupy a position corresponding to the notches on the 
mature leaf. They are hyaline, conical in form, slope sharply forwards, 
and have a slight inclination towards the upper surface of the leaf (PL 
LXXIX, Fig. 4). On the next younger leaf—and frequently also on the one 
following—the teeth are as well developed as on the one described, though, 
owing to the small size of the leaf, they are more closely set. On the 
youngest leaf the teeth, though conspicuous, are obviously immature. 
One fact is evident: the teeth are ephemeral structures which come 
rapidly to maturity, attain their full development on the second and third 
leaves, and shrivel and disappear, as soon as the leaf which bears them 
becomes, in its turn, the outermost envelope of the bud. Their function, 
whatever it may be, must be performed whilst the leaves are still immersed 
in their bath of watery fluid. Portions of the leaf—cleared with eau de 
Javelle—show clearly that each tooth is served by one or two, sometimes 
three, of the smaller veins (PI. LXXIX, Fig. 4); these run to within a short 
distance of the base of the tooth, and there fray out into a number of 
tracheides. These are, however, continuous with a strand of epithemoid 
tissue which runs up into the core of the tooth. No water-pores are borne 
on the teeth, nor are any stomata found in their immediate neighbourhood. 
If the teeth are concerned with the excretion of water, the latter must find 
some other exit than a stomatal pore. 
The epidermis of the young leaf has a moderately thick outer wall, 
though this is feebly—if at all—cuticularized. In the second leaf of the 
bud it has already divided to form the hypoderm, though the upper cells 
have not undergone the further division by vertical walls. The epidermis 
which covers the teeth, however, consists of thin-walled cells with rounded 
contours, not covered by an incipient cuticle, and with numerous definite 
intercellular spaces between them, communicating with the interior of the 
tooth (PI. LXXIX, Figs. 5 and 8). The cells forming the core of the tooth are 
thin walled ; those towards the outside are isodiametric, those in the middle 
are elongated in the direction of the length of the tooth (PI. LXXIX 
Fig. 6). The tissue throughout is fairly closely compacted, but narrow inter¬ 
cellular spaces occur at the points where three or more cells meet (PI. LXXIX, 
Fig. 7). The central elongated cells of the tooth are continuous with a strand 
of similar cells, which communicate directly with the terminal tracheides of 
the vascular bundles. This strand of epithem is not marked off from the 
mesophyll by a definite sheath of cells. 
The leaf teeth of Archytaea are in fact hydathodes, though of 
a somewhat unusual type. The epithem tissue which forms the core, or 
even the whole tissue of the tooth, has the same relation to the vascular 
bundle as has been shown to exist in Tropaeolum , Primida , Geranium , and 
