Key B

Leaves simple, 3-lobed, the margins constricted near the base of the anterior lobe.

la. Posterior lobes usually more or less orbicular; lower blade surface glossy, yellow-green when dry; primary lateral veins numerous, prominent, more or less straight and parallel; tepals yellow. ............................. A. panduriforme Schott.

2a. Basal lobes at more or less right angles to the anterior lobe. If not

3a. Plants scandent with long internodes; spadix yellow-green to yellow; berries violet-purple. ............................... A. subsignatum Schott

3b. Plants more or less acaulescent with short internodes; spadix neither yellow-green nor yellow; berries red or violet-purple.

4a. Posterior lobes curved toward anterior lobe; spadix creamy-white or greenish to reddish-brown; berries red, at least at apex. ........... A. tilaranense Standl.

4b. Posterior lobes extended away from anterior lobe; spadix green tinged with violet-purple; berries violet-purple. ................. A. seleri Engl.

2b. Basal lobes not at more or less right angles to anterior lobe.

5a. Posterior lobes broadly rounded, the sinus usually spathulate; spadix violet-purple; blade margin often undulate; Costa Rica to Ecuador.......... A. brownii Mast.

5b. Posterior lobes narrow, the sinus not spathulate; spadix usually greenish; blade margins not markedly undulate; Mexico and Guatemala.

6a. Blades with the posterior lobes usually longer than the anterior lobe; the margin between the anterior and posterior lobes straight to convex; the collective vein arising usually from the uppermost basal vein in the anterior lobe. ................................. A. berriozabalense Matuda

6b. Blades with the posterior lobes usually shorter or no longer than the anterior lobe; the margin between the anterior and posterior lobes usually markedly concave; the collective vein arising from one of the lowermost basal veins and extending along the margin of both the posterior and the anterior lobes......... A. seleri Engl.