Key1

KEY 1 BLADES DEEPLY LOBED OR DIVIDED

1a. Blades deeply pinnnately lobed, the divisions extending at least 1/4 of the way to the midrib. If not

2a. Leaves bipinnately lobed, the blade divisions near the middle of the blade pinnately lobed, 3a. Blades lobed only 4/10 to 7/10 the way to the midrib; Mexico (Sinaloa & Nayarit); 0-370 m.
P. dressleri G.S. Bunting

3b. Blade deeply lobed, the divisions extending more than 7/10 of the way to the midrib.

4a. Blades deciduous during the dry season; leaf segments thin, drying papyraceous, pale yellow-green to yellow-brown, with the minor veins distinctly visible, darker than surface; lateral segements with usually 3 or more lobes per side, extending to below the middle of the pinnae; Mexico (Jalisco & Chiapas) to El Salvador, Guatemala, Honduras and Nicaragua, 300-1,500 m.
P. warszewiczii K. Koch & Bouché

4b. Blades never deciduous during the dry season; leaf blade segment subcoriaceous, drying dark brown or sometimes reddish brown, the minor veins not distinctly visible, on drying, not markedly darker than surface; lateral segments with usually 1-2 lobes per side, usually restricted to near the apex of the pinnae; Mexico to Colombia but in Mexico on the Caribbean slope, 0-500, rarely to 1,860 m.
P. radiatum Schott var. radiatum

2b. Leaves merely pinnately lobed, the blade divisions near the middle of the blade, not bipinnately lobed, divided less than 1/2 the way to the midrib.
P. radiatum Schott, var. pseudoradiatum Croat

1b. Blades deeply 3-lobed or trisect.

5a. Blade with the anterior lobe less than 1.7 times longer than the lateral lobes; lateral lobes directed more or less toward the apex, roughly paralleling the median lobe. If not 6a. Lateral lobes of the blade broadly confluent with the medial lobe by at least 2 cm from the base of the blade (as measured from the depths of the incised area and the apex of the petiole); inflorescences usually 3-9 per axil. 7a. Medial lobe of the blade with 5-12 pairs of primary lateral veins; Honduras to Panama, usually below than 1,000 m.
P. rothschuhianum (Engl.) Croat & Grayum

7b. Medial lobe of the blade with 18-19 pairs of primary lateral veins; Costa Rica (Puntarenas, San José), 1,000-1,250 m.
P. cotobrusense Croat & Grayum

6b. Lateral lobes of the blade not confluent with or only weakly confluent with the medial lobe to no more than 1 cm from the base of the blade; inflorescences usually one, rarely to 3 per axil.

8a. Median lobe of blades with more than 18 pairs of primary lateral veins, elliptic; central Panama, 350-450 m.
P. madronoense Croat

8b. Median lobe of blade with fewer than 12 pairs of primary lateral veins, usually oblanceolate to oblong-lanceolate; widespread species, Mexico to Ecuador.

9a. Medial lobes mostly 3-3.5 times longer than broad (rarely to 1.7 times longer than broad); primary lateral veins of medial lobe 4-12 per side, prominently sunken; lateral lobes directed more or less toward the apex; Mexico to Ecuador, 0-1,300 m.
P. tripartitum (Jacq.) Schott

9b. Medial lobes mostly 1.5-2 times longer than broad; primary lateral veins mostly 2-4 rarely 5 per side, weakly sunken; lateral lobes directed more or less outward; Mexico to Costa Rica, 250-1,800 m.
P. anisotomum Schott

5b. Blades with the anterior lobe more than 1.7 times longer than the lateral lobes; lateral lobes directed laterally (spreading) or even toward the base of the petiole (reflexed). 10a. Blades sagittate, the lateral lobes directed somewhat toward the base; Mexico to Panama and South America, 0-1,900 m P. mexicanum Engl.. 10b. Blades hastate, the lateral lobes directed outward at ca. 90E angle.
11a. Lateral lobes confluent to the medial lobes usually more than 4 cm (rarely to 3.3 cm); basal veins 8-10 per side; Honduras to Panama, 0-680 m. P. angustilobum Croat & Grayum

11b. Lateral lobes confluent to the medial lobe usually less than 3 cm (rarely to 8 cm); basal veins 4-7 per side; Mexico to Costa Rica, 250-1,800 m.
P. anisotomum Schott