1	Leaf blade transverse-cordiform in outline, pedately compound	2
–	Leaf blade cordiform-sagittate, sagittate or hastate in outline, margins entire, repand, sinuately lobed, pinnatifid or bipinnatifid	3
2	Ovary locules 3–4; leaflets 8–11, central leaflet 10–17 cm long; occurring on rocks in semi-arid areas or terrestrial in coastal restinga scrub on sand; usually in association with populations of Bromeliaceae; northeast Brazil	T. leal-costae
–	Ovary locules 10–26; leaflets 10–20, central leaflet 18–50 cm long; hemiepiphytic or terrestrial; most common along river margins; Amazon basin	T. spruceanum
3	Leaf margin sinuately lobed, pinnatifid or bipinnatifid	4
–	Leaf margin entire or repand or, if sinuately lobed, then peduncle 16 cm long or more	11
4	Leaf margin bipinnatifid, rarely pinnatifid but then with primary lateral veins of anterior division (5-)6–9(-10) per side; leaf blade over 50 cm long, primary lateral lobes (12-)17–35(-55) cm long	5
–	Leaf margin undulate or pinnatifid; if pinnatifid, then with primary lateral veins of anterior division 3–4(-10) per side; leaf blade up to 50 cm long, usually smaller; primary lateral lobes 5–17.5 cm long	7
5	Petioles flattened or slightly convex adaxially; intravaginal squamules never persistent, foliage leaf scars always concolorous with the internodes; uplands of Cerrado (Minas Gerais, Bahia and Goiás states – 700–1200 m)	T. lundii
–	Petioles conspicuously sulcate adaxially; intravaginal squamules persistent, very rarely deciduous (if deciduous, then foliage leaf scars discolorous with the internodes)	6
6	Intravaginal squamules numerous and dense, 5–12 mm long, 2–4 mm wide at base, persistent but easily detachable, rarely deciduous; female portion of the spadix adnate to the spathe for 60–80% of its length; southern and western (coastal) Brazil, Argentina, Paraguay	T. bipinnatifidum
–	Intravaginal squamules few and scattered, robust, 8–20 x 5–10 mm, always persistent, hardly detachable; female portion of the spadix adnate to spathe for 40–50% of its length; northern Goiás and possibly Mato Grosso states	T. mello-barretoanum
7	Plants aquatic or rarely terrestrial; leaf margin sinuately lobed (sinuses penetrating less than halfway to midrib), primary lateral lobes of anterior division 1.5–6.5(-14) cm long, usually oblique and turned towards leaf apex; female zone of the spadix (1.5-)4–5 cm long	8
–	Plant rupiculous or terrestrial; leaf margin pinnatifid (sinuses penetrating at least halfway to midrib), primary lateral lobes of anterior division 5–17.5 cm long, not oblique, female zone of the spadix 1.4–3.4 cm long	9
8	Stems with long and thorn-like intravaginal squamules; leaf blades never erect in living plants; Argentina, Paraguay, Bolivia and Brazil (South and South-eastern)	T. undulatum
–	Stems without persistent intravaginal squamules; leaves always erect or semi-erect in living plants; Eastern Brazil (northern Espírito Santo and southern Bahia)	T. paludicola
9	Petiole green or glaucous green at apex; leaf blade broadly ovate in outline, dark to subglossy green, sometimes glaucous, primary lateral lobes 3–4(-5); spathe 6.4–16 cm long, green outside, opened at anthesis; ovary locules 4–8(-11)	10
–	Petiole purplish at apex; leaf blade triangular to ovate in outline, glossy dark green, primary lateral lobes 5–10; spathe (8.2-)12–18 cm long, dark purple outside, tightly clasped around spadix at anthesis; ovary locules (6-)7–8	T. xanadu
10	Leaf blade (32-)35–50 cm long, primary lateral lobes of anterior division 3.5–6.3(-7.5) cm wide, distance between sinuses and midrib progressively greater towards base of anterior division; fertile male zone of the spadix 1.5–2.2 cm diam.	T. saxicola
–	Leaf blade 17-33 cm long, primary lateral lobes of anterior division 1.4–3.7(-7.4) cm wide, distance between sinuses and midrib usually becoming progressively less towards base of anterior division; fertile male zone of spadix 0.85–1.3 cm diam.	T. adamantinum
11	Overall length of adult leaf blade more than 60 cm (sometimes 50–60 cm in T. solimoesense); petiole apex often minutely rugose-verruculate (may be smooth in T. stenolobum)	12
–	Overall length of leaf blade less than 60 cm, petiole apex smooth, never occurring in Amazonia	16
12	Species from Eastern Brazil; stamens 6 mm long or more; staminodes more than 1.6 mm wide at apex, less than 2.5× longer than wide; ovary locules 6–13 per ovary	13
–	Species from Amazonia; stamens less than 6 mm long; staminodes less than 1.6 mm wide at apex, more than 2.5× longer than wide; ovary locules 17–34(-47) per ovary	15
13	Leaf blade narrowly sagittate, sometimes subhastate; anterior division 2.1–3.3× longer than wide; intravaginal squamules deciduous	T. stenolobum
–	Leaf blade broadly sagittate; anterior division 1–1.5× longer than wide; intravaginal squamules small but persistent	14
14	Leaf blade less than twice as long as wide; spathe outside lacking extrafloral nectaries, inside carmine magenta at anthesis; central style dome lacking	T. speciosum
–	Leaf blade more than twice as long as wide; spathe outside with punctate, pale brown extrafloral nectaries, inside cream-white at anthesis; central style dome present	T. williamsii
15	Cataphylls persistent; primary lateral veins of anterior division of leaf blade (5-)6–7; ovary locules 17–22; style elongated, distinctly narrower than ovary and lacking an axial canal	T. venezuelense
–	Cataphylls deciduous; primary lateral veins of anterior division of leaf blade (3-)4–5(-6); ovary locules 26–34(-47); style short, as broad as ovary with an axial canal or cavity which is very conspicuous in fruit	T. solimoesense
16	Peduncle subequal to twice as long as spathe; plants aquatic or rupiculous, aerial portion of the stem unbranched; internodes shorter than prophyll scars	17
–	Peduncle only about one third of spathe length; plant hemi-epiphytic or terrestrial; aerial stem branching frequently; internodes usually longer than prophyll scars	T. corcovadense
17	Leaf blade at least twice as long as broad; style longer than ovary	T. dardanianum
–	Leaf blade much less than twice as long as broad; style shorter than ovary	18
18	Intravaginal squamules abundant; broadly triangular, 3–12 mm long, (1.5-)3–7(-9) mm broad at base; style body as wide as ovary	T. brasiliense
–	Intravaginal squamules few, more narrowly triangular, 1.5–5 mm long, 0.5–2.5 mm broad at base; style body slightly narrower than ovary	19
19	Leaf blades subglossy to glaucous green, margins weakly repand; Argentina, Paraguay, Uruguay, South Brazil	20
–	Leaf blades dark glossy green, margins entire, rarely repand; central Brazil	T. uliginosum
20	Plants rupiculous, stem erect; prophyll deciduous; stylar central dome present	T. petraeum
–	Plants aquatic, stem decumbent or rhizomatous subterranean; prophyll marcescent and persistent; stylar central dome absent	T. tweedieanum