Table 2.

Percentage of genera of Ferns, Gymnosperms and Angiosperms with nodal transfer cells.

Taxon/ sub taxon	No of genera	Percent genera with transfer cells
Ferns	16	69
Gymnosperms	10	50
Angiosperms
Monocot	13	39
Eudicot	116	70

Data are derived from a survey of 61 families by Gunning et al. (1970) in which no distinction is made between xylem and phloem transfer cells. In their survey Gunning and co-workers emphasized that “negative results must be viewed with caution since in certain cases the zone of transfer cell formation” (within the node) “is known to be extremely localized.”