Inter-petiolar stipules of Galium mollugo L

Abstract

The inter-petiolar stipules of Galium mollugo are separate, leaf-like in shape and size, and also in the possession of a single trace bundle. Morphogenetical studies at the shoot apex show that the initiation and vascularization of the leaves and stipules are different. Only the leaves bear axillary buds; the leaf-like stipules do not bear them. The foliar foundations by their union form acollar round the axis, from which it separates by the differentiation of a separation layer in its adaxial surface. The glandular hairs also arise from this layer. The axis on its separation shows a wavy contour of its surface. The crest of each initially shallow wave is occupied by a meristem which helps in the development of each ridge. From later behaviour of the apparently single leaf-trace bundle it appears that it is composed of three bundles and the laterals are concerned with the origin of the stipules and their traces.