"melastome" look; pistils often prominently exserted and quadrangular; ovules and seeds 1 per locule.
section Digitinervium  Sodiro

Leaf blades with usually no more than one pair of basal veins (usually merely the collective vein) extending along the margin to the apex; primary lateral veins usually not numerous and closely parallel; pistils exserted or not, not usually quadrangular; ovules and seeds usually 2 or more per locule

7.

8.

Plants usually scandent; stems slender, mostly less than 6 mm diam.; internodes somewhat elongate; berries acute at apex; throughout the range of the genus.
section Tetraspermium Schott

Plants usually more or less caespitose, at least lacking slender stems; stems usually more than 1 cm diam.; berries often more or less truncate and indented at the apex (not true of A. hookeri  from N.E. South America and Lesser Antilles); principally from Costa Rica to Ecuador, especially western South America.

8.

9.

Plants large, with "bird's-nest" habit; leaf blades with scalariform venation (i.e., with the tertiary veins extending in almost straight lines between the primary lateral veins); Trinidad, Surinam and Lesser Antilles as far north as St. Kitts A. hookeri  Kunth (Alliance unknown, not Pachyneurium).

Plants usually with medium-sized leaves and usually not with distinct "bird's-nest" habit; leaf blades lacking scalariform venation, the tertiary veins irregularly anastomosing or at least not running in almost straight lines between the primary lateral veins.
section Porphyrochitonium Schott

9.

5.

Leaf blades epunctate or at least not conspicuously dark glandular punctate.

10.

Vernation of leaf blade involute (i.e., with both margins rolled inward toward the midrib); plants frequently with "bird's-nest" habit; blades often thick, frequently more or less oblanceolate or obovate to elliptic.
section Pachyneurium Schott

10.

Vernation of leaf blades supervolute (i.e., with one margin rolled inward toward the midrib and the alternate margin rolled around the midrib and the rolled up opposite

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