Table 1. Main characteristics of tissues from leaf apical hydathodes of maize, rice, Brachypodium distachyon and sugarcane.

Tissue	Maize var. P1524	Rice var. Kitaake	Brachypodium distachyon	Sugarcane var HOCP04838, Q155 or CAS2
Leaf tip shape	Gutter-like	Highly rolled	Rolled	Needle-like spike to gutter-like
Location of hydathodes	Apical and marginal	Apical	Apical	Sub-apical and marginal
Epidermis	No or few trichomes; epicuticular waxes	Many trichomes and spicules; epicuticular waxes	Many trichomes; epicuticular waxes	Some trichomes; epicuticular waxes
Location of water pores	At leaf tip and along leaf margin over several mm	At leaf tip and gutter	At leaf tip and gutter	Below the spike and along leaf margin over several cm
Epiculticular waxes on water pores	None or little	Little	Little	None or little
Other features of water pores	Often opened, absence of subsidiary cells
Chambers below water pores	Large	Large	Small	Large
Epithem	Loose tissue; thin cell walls, numerous meatuses	Very reduced and loose	Reduced but compact; surrounded by a compact parenchyma with thick cell walls	Reduced but compact; surrounded by a compact parenchyma with sometime thickened cell walls
Connection of vessel elements to water pore chambers	Separated by few epithemal cells; connection via meatuses	Sometimes direct	Separated by some epithemal cells	Separated by some epithemal cells