NODAL ANATOMY AND THE MORPHOLOGY OF STIPULES 45 1 
however, usually seems to be necessary for the production of a definite 
stipular appendage instead of a mere rounded swelling. 
What light, then, do these anatomical facts throw on the vexed 
question of the morphology of stipules? They lend little support 
to the theories that these structures are independent organs, vestiges 
of a sheath of fused leaves or lateral leaflets of a compound leaf, but 
rather favor the contention that stipules are integral portions of the 
base of the leaf, a view which is well expressed by Eichler when he 
says that stipules arise without exception as a product of the leaf -base 
of the primordial leaf. Anatomical facts are also in agreement with 
the theory frequently put forward that stipules, the sheathing leaf -base, 
the ochrea, the stipular appendages of the lower monocotyledons and 
the tendrils and ligule of the higher ones are morphologically identical, 
for the character and position of these various structures is to a large 
extent dependent on the type of nodal topography and the manner in 
which the base of the leaf is innervated. The so-called stipules of 
ferns and gymnosperms are not dependent on nodal anatomy and are 
therefore apparently not to be regarded as homologous with those of 
angiosperms. 
As to just what is the morphological character of stipules we cannot 
be quite sure, but the results of the present investigation indicate 
that they may perhaps be considered as the two earliest leaf -teeth, 
their position being determined by that of the two lateral traces rather 
than by that of the vascular bundles of the lamina, as in the case of 
ordinary teeth. They may also be regarded as two basal leaf lobes, 
although the difference between a tooth and a lobe seems to be more 
one of degree than of kind. The function of stipules as bud scales 
in certain families apparently does not indicate their true morpho- 
logical nature but is rather to be looked upon as a secondary adapta- 
tion. 
As to the phylogeny of stipules there seems to be considerable 
doubt. The bulk of opinion, expressed by many writers and recently 
emphasized by Domin (2) in a series of papers, is that a ligule or 
sheathing leaf-base is the most primitive condition and that this 
has gradually degenerated, in many families of dicotyledons, into two 
stipules. The facts brought forward in the present paper show that 
the character of the leaf-base, whether sheathing, stipulate or devoid 
of appendages, depends closely upon whether the node is multilacunar, 
trilacunar or unilacunar, respectively. The question as to which 
