64 MANUAL OF BOTANY 



the ultimate wings but little developed, the leaf is called decom- 

 pound. When the branching is not monopodial but cymose, we 

 ha,ye palmate, palmatifid, or 2}almatisected \earves, the degree of 

 fusion between the wings of the branches being thereby indi- 

 cated. In such leaves the primary axis of the phyllopodium 

 does not enter into the composition of the lamina. Cymose 

 branch systems sometimes show branches of the third -order, as 

 in the pedate or pedatipartite leaf (fig. 104). 



It is not mrusual to find both types of branching represented 

 in the same leaf. Frequently in the palmate varieties we find 

 that while the main branches arise cymosely, each forms a 

 monopodium. The nature of the branching may generally be 

 ascertained by an inspection of the arrangement of the veins or 

 vascular bundles, as shown in fig. 103, the palmatifid leaf of the 

 Castor-oil plant. Here the phyllopodium gives rise cymosely to 

 seven branches, each of which develops monopodially. 



Generally the branches of the epipodium all lie in one plane, 

 so that the leaf is flattened with its face towards the stem. In a 

 particular variety of the palmate form known as the peltate leaf 

 (fig. 105) this rule is departed from, the petiole being apparently 

 attached to the centre of the leaf-blade, the plane of which is 

 thus almost at a right angle to the direction of the stalk. This 

 is due to the fact that the younger branches grow out in front 

 of the petiole, instead of in the usual lateral plane, and their 

 wings being coherent with each other, the petiole becomes 

 apparently attached to the middle of the lamina. 



When the epipodium remains cylindrical, and bears only 

 branches of the first order which are winged, constituting a 

 number of leaflets, these may show at their bases certain out- 

 growths resembling the stipules of the primary leaf-base. These 

 are known as stipels ; they are present in certain Leguminosce, 

 as Phaseoliis. 



When the mesopodium or petiole is absent, the hypopodium 

 or leaf-base may be winged, and its wings continuous with those 

 of the lamina. The stem thus seems to be surrounded by the 

 expanded base of the latter. If two leaves arise on the stem at 

 the same node, their wings sometimes coalesce. We have thus 

 formed the varieties known as auriculate, jyerfoUate, or connate 

 leaves (figs. 106 and 107). 



The flattened portion of the epipodium is always found to be 

 strengthened and supported by certain strands of woody tissue 

 which traverse it in various directions. In thin leaves these are 

 visible as projections on the under surface, but in thick or sue- 



