Preliminary Key to Natural Groups of Anthurium

1.

Leaf blades prominently 3-lobed or palmatified to palmatisect

2.

Leaf blades divided into 3 segments

3.

Leaf segments fully free to the base

section Dactylophyllium Engl.

3.

Leaf segments united at the base

section Semaeophyllium Schott

2.

Leaf blades divided into 5 or more segments

4.

Leaf segments free to the base

section Dactylophyllium Engl.

4.

Leaf segments united at base (the central one may be free)
section Schizoplacium  Schott

1.

Leaf blades entire, may be lobed at the base but not prominently 3 or more lobed.

5.

Leaf blades conspicuously dark glandular-punctate at least on the lower surface.

6.

Blades cordate, hastate or otherwise, with usually definite posterior lobes; most basal veins usually merging with the margin of the blade below the middle of the blade (i.e., not mostly extending to above the middle of the blade as in section Digitinervium), the blade thus lacking a "melastome" look; species restricted to Mexico and Middle America. Section Cordatopunctatum , sect. nov. previously referred to as sect. Belolonchium Schott (A. verapazense  Alliance) in Croat (1983). Note: [This group includes A. chiapasense Standi., A. lucens Standl. ex Yuncker, A. riograndicolum  Matuda and A. longipeltatum  Matuda.]

Blades either acute to obtuse or subcordate at base with usually only a single collective vein extending along the margin to the apex (section Porphyrochitonium)  or with several basal veins prominently arcuate- ascending to the apex with many, close, parallel primary lateral veins extending between all the basal veins giving the blade the appearance of a "melastome" leaf blade
(section Digitinervium).

6.

7.

Leaf blades with several pairs of the basal veins sharply arcuate- ascending, extending to or almost to the apex; primary lateral veins numerous, distinct, parallel and extending in more or less straight lines between all the basal veins giving the leaf blade a

2