Vascular bundles dorsal

Between each fibro-vascular bundle and the tip of each rib will be found a zone of collenchyma cells. In the mesocarp between each two ribs on the dorsal side occurs a single vitta or oil tube which is lined with a layer of brownish polygonal cells. These vittae contain the official oil of fennel. Two vittae generally occur in the meso-carp of the commissural side although four are reported to have been found in this region of some fennel fruits. 

The sepals have three main vascular traces, and there are up to seven branches formed by successive lateral branching (Fig 8.6A-E). The petals and stamens have a single vascular trace (Fig 8.6A-E). In petals, up to ten vascular bundles may be present (Fig 8.6A-D). In carpels the median dorsal vasculature forms a more or less... 

A diffuse or weakly differentiated carpel dorsal vasculature, such as in Nitraria and Peganum, is a feature that appears to be relatively pronounced in Sapindales (Ronse De Craene and Haston, 2006 Bachelier and Endress, 2008, 2009). Also, inverted synlateral vascular bundles have been reported in Sapindales, such as in some Burseraceae (Stevens, 2001 onwards Bachelier and Endress, 2009). 

In Nitraria and Peganum, the sepals have three vascular traces and the petals one vascular trace, as is common in eudicots. The dorsal vasculature of the carpels appears as broad reticulate bands of anastomosing bundles. The synlateral bundles are inverted and have the xylem in peripheral position (for Nitraria, see also Shukla, 1955 Nair and Nathawat, 1958 for Peganum, see also Beille, 1902). 

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