Key for Pourouma Aubl.

1Stipules subpersistent.
1'Stipules caducous.
2Blade scabrous (or scabridulous) above.
2'Blade smooth above.
3Blade normally entire; sparse brown pluricellular on the branchlet. leaves and inflorescences; pistillate inflorescence with 3-8 flowers.
3'Blade normally 3-7-lobed to -parted, if entire, then dense brown pluricellular hairs on branchlets, leaves and inflorescences; pistillate inflorescences with 10-50 flowers.
4Stipules with ± dense, yellow hairs inside; reticulum at the lower lear surrace slightly prominent to plane and mostly covered with arachnoid hairs; blade mostly entire or 5-fid to -parted; fruiting perianth often scabrous.
4'Stipules glabrous or with sparse white hairs inside; reticulum at the lower leaf surface prominent and usually not covered by arachnoid hairs; blade mostly 3-lobed to -fid; fruiting perianth subvelutinous.
5Blade entire or 3-lobed to -fid.
5'Blade 5-7(-9)-fid to -parted.
6Basal secondary veins unbranched; blade always entire.
6'Basal secondary veins branched; blade entire or lobed to parted.
7Stipules 1-3 cm long; pistillate inflorescence branched.
7'Stipules normally longer than 3 cm; pistillate inflorescence subumbellate.
8Secondary veins 5-9 pairs.
8'Secondary veins (normally) 9-17 pairs.
9Blade with appressed hairs on the veins beneath.
9'Blade with patent hairs on the veins beneath.
10Arachnoid indument on branchlets, stipules, main veins of the blade beneath, inflorescence and/or pistillate flowers.
10'Arachnoid indument normally only in the areoles and on the smaller veins of the blade beneath.
11Blade 3-5-parted, with a deeply cordate base.
11'Blade entire or 3-parted, with a truncate to subcordate base.
12Petiole and blade beneath with short, appressed hairs; lenticels of the branchlets conspicuous.
12'Petiole and/or blade beneath with rather long, patent hairs; Ienticels of the branchlets usually inconspicuous.
13Stipules glabrous inside.
13'Stipules hairy inside.
14Blade entire or 3-lobed to -fid.
14'Blade 5-7(-9)-fid to -parted.
15Pistillate flowers in 2 clusters; pedicels in fruit up to 7 mm long; staminate flower with lobed perianth; filaments much longer than the oerianth.
15'Pistillate flowers separate; pedicels in fruit up to 16 mm long; staminate Bower with deeply parted perianth; filaments shorter than or as long as the oerianth.