310 edmund w. sinnott 
Leitneriales 
Leitneria is trilacunar. 
JUGLANDALES. 
The order is prevailingly trilacunar, although five bundles and 
gaps frequently occur in Pterocarya. 
JULIANALES 
This order is trilacunar. 
Fagales 
All species of the genera of the Betulaceae and Fagaceae examined 
had invariably three bundles and three gaps {fig. 4 and photo, i). 
It is thus evident that in all those plants grouped originally under 
the inclusive order Amentiferae the fundamental type of nodal 
structure is trilacunar. This may occasionally be expanded but in 
no case is there an approximation and fusion of the three gaps into one. 
Urticales. 
All the Ulmaceae and Urticaceae examined agreed in the possession 
of a trilacunar node. This seems also to be characteristic of most of 
the Moraceae, although in Ficus there are usually five bundles and gaps. 
Proteales 
In the six genera of Proteaceae examined the nodal structure was 
invariably trilacunar. 
Santalales 
In the Santalaceae and Loranthaceae there is apparently but a 
single bundle and gap to each node, but a trilacunar condition is 
characteristic of the Olacaceae and is therefore probably ancestral for 
the order as a whole. 
ArI STOLOCHI ALES 
The node of Aristolochia is trilacunar, but the bulk of the vascular 
supply to the leaf is contained in the central bundle. The two lateral 
ones are very small and arise close together on the opposite side of the 
stem from that where the leaf is attached, pass around the stem and 
thus enter the base of the leaf. 
