Actynodroma

Actynodroma

The term actynodroma, which derives from the Greek aktís -înos ‘radius’, according to Hickey, LJ 1973, defines the rib of the leaves which is equipped with 3 or more primary ribs diverging radially from a single point (as for example in the Malvaceae , Tiliaceae).
Within this morphological characteristic there may be perfect or imperfect type ribs depending on the development of these in the leaves:
– it is defined as perfect when the branching of the lateral ribs covers at least 2/3 of the area of ​​the lamina;
– is instead imperfect in the opposite case.
The rib of a leaf is considered perfect when it is:

– marginal if the nerves reach the margin;
– reticulated if the nerves do not reach the leaf margin;
– basal if the point of radiation of the primary veins is at the base of the leaf limb;
– above basal if it is above.
The rib is instead imperfect if it is:
– marginal, when the nerves reach the leaf margin;
– reticulated when the nerves do not reach it.