Key to Species of Philodendron Subgenus Philodendron


Based on Croat, Delannay, Duncan & Kostelac, 2015

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1A. Plants with stems or petiolePetiole: Leaf stem. s densely scaly (or only scaly near the apexApex: End forming a point. of the petiolePetiole: Leaf stem. in young specimens of Philodendron squamipetiolatum).
2A. Stems and petiolePetiole: Leaf stem. s both densely scaly, leaves deeply cordateCordate: with prominent posteriorPosterior: lobes.
3A. Blades dark green above, with midrib and primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s much paler; primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 3-6 pairs, conspicuously branched near leaf margin .. 📌Philodendron verrucosum
3B. Blades medium green above, with midrib and primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s concolorous; primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 5-12 pairs, mostly unbranched .. 📌Philodendron squamicaule
2B. Stems not densely scaly, petiolePetiole: Leaf stem. s mostly densely scaly, except only near the apexApex: End forming a point. on young specimens, leaves rounded or subcordateCordate: at the base .. 📌Philodendron squamipetiolatum
1B. Plants not densely scaly on the stems or the petiolePetiole: Leaf stem. s.
4A. Blades rounded, attenuate or only slightly cordateCordate: at the base, never deeply lobed (note that the most mature leaves of Philodendron delannayi are generally deeply cordateCordate: -sagittateSagittate: ).
5A. Blades elongate, always more than 3 times as long as wide.
6A. PetiolePetiole: Leaf stem. s very short, less than 1/6 the length of the blade; blades oblanceolateLanceolate: , 24-78 cm long, 3-4 times as long as wide, narrowly rounded or attenuate at the base; primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 20-29 pairs .. 📌Philodendron oblanceolatum
6B. PetiolePetiole: Leaf stem. s generally longer than 1/6 the length of the blade (except sometimes for P. bonifaziae).
7A. Blades 4-9 times as long as wide.
8A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s obscure on both surfaces; blades oblanceolateLanceolate: , cordulate at the base, 34-54 cm long, 4-7 times as long as wide, 2.7-6 times as long as petiolePetiole: Leaf stem. .. 📌Philodendron bonifaziae
8B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s well visible.
9A. Blades long-lanceolateLanceolate: , long-tapering or sometimes rounded at the base, 37-61 cm long, 5-9 times as long as wide, 1.3-2.3 times as long as petiolePetiole: Leaf stem. ; primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s numerous and closely spaced .. 📌Philodendron jimenae
9B. Blades lanceolateLanceolate: , rounded and cordulate at the base, 34-50 cm long, 4.5-5.7 times as long as wide, 2.3-3.7 times as long as petiolePetiole: Leaf stem. ; primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 7-9 pairs, widely spaced .. 📌Philodendron mentiens
7B. Blades 3-4.3 times as long as wide.
10A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s obscure on both surfaces, blades lanceolateLanceolate: , attenuate at the base, 28-43 cm long, 3-4.3 times as long as wide, 2.6-5.4 times as long as petiolePetiole: Leaf stem. ; drying black .. 📌Philodendron melanum
10B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s well visible.
11A. Blades obovateOvate: to ellipticElliptic: , tapering into a narrow subcordateCordate: base, 25-44 cm long, 3-4.1 times as long as wide, 3.6-5.8 times as long as petiolePetiole: Leaf stem. ; primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 5-13 pairs, widely spaced and curving upward quickly; drying brown .. 📌Philodendron baudoense
11B. Blades lanceolateLanceolate: , cuneateCuneate: at both ends, ca. 23 cm long, 3.3-3.6 times as long as wide, 2.3-2.8 times as long as petiolePetiole: Leaf stem. ; primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s ca. 13 pairs, curving upwards towards the edge of the blade; drying dark green above, lighter green below .. 📌Philodendron angosturense
5B. Blades ovateOvate: , ovateOvate: -lanceolateLanceolate: or ellipticElliptic: , generally less than 3 times as long as wide (but up to 4 times as long in Philodendron clarkei, Philodendron hannoniae, Philodendron heleniae subsp. heleniae, Philodendron tenuipes and juvenile blades of Philodendron delannayi).
12A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s obscure or scarcely visible.
13A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s mostly obscure; petiolePetiole: Leaf stem. sheathed for most of its length; blades ovateOvate: -lanceolateLanceolate: , subcordateCordate: at the base, 17.5-27 cm long, 2.2-2.9 times as long as wide, 2-3.5 times as long as petiolePetiole: Leaf stem. ; drying palebrown .. 📌Philodendron mansellii
13B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s scarcely visible, but still somewhat distinct; petiolePetiole: Leaf stem. not sheathed for most of its length.
14A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s ca. 10 pairs; blades ovateOvate: , rounded to weakly subcordateCordate: at the base, ending with a long acumen, widest near the base, 23-25 cm long, 13-14 cm wide, ca. 1.7 times as long as wide, 1.6-1.9 times as long as petiolePetiole: Leaf stem. ; drying brownish green above and brown below .. 📌Sterile species #1
14B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 4-6 pairs; blades less than 23 cm long.
15A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 5-6 pairs; blades ovateOvate: -ellipticElliptic: , broadly cuneateCuneate: or rounded at the base, 11-23 cm long, 1.6-2 times as long as wide, 1.6-3.6 times as long as petiolePetiole: Leaf stem. ; drying black or dark brown .. 📌Philodendron ellipticum
15B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 4-6 pairs; blades ovateOvate: -ellipticElliptic: , rounded at the base, 16-19.5 cm long, 1.9-2.3 times as long as wide, 1.7-2.4 times as long as petiolePetiole: Leaf stem. ; drying pale brownish green .. 📌Philodendron coriaceum
12B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s prominent.
16A. PetiolePetiole: Leaf stem. s sulcateSulcate: Furrowed; grooved. .
17A. Blades often subcordateCordate: , sometimes rounded at the base.
18A. Blades ovateOvate: -subcordateCordate: , ca. 66 cm long, 1.8 times as long as wide, 0.9 times as long as petiolePetiole: Leaf stem. ; primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s ca. 9 pairs, widely spaced, deeply quilted-sunken above; drying black .. 📌Philodendron anthracyne
18B. Blades ovateOvate: or ovateOvate: -ellipticElliptic: , subcordateCordate: or rounded at the base, 21-51cm long, 1.4-2.7 times as long as wide, 0.7-1.4 times as long as petiolePetiole: Leaf stem. ; primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 8-14 pairs, weakly to narrowly sunken or weakly quilted; drying dark grayish brown to yellowish brown .. 📌Philodendron lentii
17B. Blades generally not subcordateCordate: .
19A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s widely spaced, generally 2 cm or more apart; blades pendent, ovateOvate: -lanceolateLanceolate: to oblongOblong: , rounded at the base, with sides mostly parallelParallel: Parallel Venation. until converging as a broad triangle at the apexApex: End forming a point. , 2.3-4 times as long as wide; drying light greenish brown .. 📌Philodendron hannoniae
19B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s less than 2 cm apart
20A. PetiolePetiole: Leaf stem. s deeply sulcateSulcate: Furrowed; grooved. ; blades ovateOvate: -ellipticElliptic: , rounded or obtuse at the base, broadest below the middle, 19-42 cm long, 1.4-2.5 times as long as wide, 1.1-2.2 times as long as petiolePetiole: Leaf stem. ; drying green or light brown .. 📌Philodendron profundisulcatum
20B. PetiolePetiole: Leaf stem. s narrowly and sharply sulcateSulcate: Furrowed; grooved. ; blades ovateOvate: -lanceolateLanceolate: , rounded or sometimes cuneateCuneate: at the base, broadest near the middle, 29-49 cm long, 1.9-3.5 times as long as wide, 1.5-2 times longer than petiolePetiole: Leaf stem. ; drying dark brown above and lighter brown below .. 📌Philodendron tenuipes
16B. PetiolePetiole: Leaf stem. s not significantly sulcateSulcate: Furrowed; grooved. .
21A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s widely spaced, generally 2 cm or more apart.
22A. Midrib thick, main veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s generally much paler than blade.
23A. Internodes moderately fissured transversely; blades ovateOvate: -lanceolateLanceolate: , subcordateCordate: , never deeply cordateCordate: , widest near the base, 47-62 cm long, 1.8-3.1 times as long as wide, 1.3-2 times as long as petiolePetiole: Leaf stem. ; drying pale brown .. 📌Philodendron luteonervium
23B. Internodes deeply fissured transversely, sap oozing like butterscotch, turning dark orange; blades ovateOvate: -lanceolateLanceolate: , attenuate or subcordateCordate: at the base, becoming deeply cordateCordate: on older plants, widest near the base, 34-67 cm long, 1.2-2.6 times as long as wide, 1.0-1.6 times as long as petiolePetiole: Leaf stem. ; drying dark green or brownish green; (juvenile blades oblanceolateLanceolate: -ellipticElliptic: , long-tapering into the petiolePetiole: Leaf stem. at the base, 2.8-4.7 times as long as wide.) .. 📌Philodendron delannayi
22B. Midrib not particularly thick, main veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s not much paler than blades.
24A. Blades narrowly ovateOvate: , weakly subcordateCordate: , sometimes obtuse, truncate or rounded at the base, upper surface drying yellow-brown, lower surface drying yellowish to reddish brown, with dark secretory canals .. 📌Philodendron heleniae subsp. heleniae
24B. Blades oblongOblong: -oblanceolateLanceolate: , rounded at the base; drying black or dark brown .. 📌Philodendron clarkei
21B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s less than 2 cm apart.
25A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s often branched, numerous; blades ellipticElliptic: , occasionally subcordateCordate: at the base, broadest near the middle, 56-83 cm long, 1.8-2.6 times as long as wide, 1.1-1.3 times as long as petiolePetiole: Leaf stem. ; drying brown .. 📌Philodendron bethoweniae
25B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s not branched; petiolePetiole: Leaf stem. s strongly arching toward apexApex: End forming a point. ; blades ovateOvate: -subcordateCordate: to slightly cordateCordate: , broadest in basalBasal: Forming or belonging to a bottom layer or base. 1/3, 23-38 cm long, 1.4-1.7 times as long as wide, 0.7-1.4 times as long as petiolePetiole: Leaf stem. ; drying green or greenish brown .. 📌Philodendron curvipetiolatum
4B. Blades deeply lobed, cordateCordate: , hastateHastate: or sagittateSagittate: .
26A. Blades trisected almost to the base into three similar segments, median segment usually oblanceolateLanceolate: , 15-45 cm long, 1.9-7.8 times as long as wide, 1-1.5 times as long as lateral segments, lateral segments inequilateral .. 📌Philodendron tripartitum
26B. Blades not deeply trisected.
27A. Blades elongate or triangular, sagittateSagittate: or hastateHastate: , never ovateOvate: -cordateCordate: .
28A. Blades elongate and cordateCordate: /sagittateSagittate: , with lobes projecting mostly toward the base (ie parallelParallel: Parallel Venation. to the midrib).
29A. Blades, sagittateSagittate: -lanceolateLanceolate: ; posteriorPosterior: lobes long, triangular or acute, primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s more than 13 pairs, arising at close to a 90 angle.
30A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 13-18 pairs; blades 16-93 cm long, 1.8-4 times as long as wide, 1-2.1 times as long as petiolePetiole: Leaf stem. ; drying medium brown .. 📌Philodendron sharoniae
30B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s more than 20 pairs.
31A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s ca. 25 pairs; blades 84-88 cm long, 2.2-2.5 times as long as wide, 0.9 times as long as petiolePetiole: Leaf stem. s, lower surface with prominent laticiferLaticifer: A laticifer is a type of elongated secretory cell found in the leaves and/or stems of plants that produce latex and rubber as secondary metabolites. s visible, cross-veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s essentially lacking; drying dark brown above, reddish brown below .. 📌Philodendron pambilarense
31B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 33-36 pairs; blades 97-122 cm long, 2.2-3.1 times as long as wide, 0.97-1.1 times as long as petiolePetiole: Leaf stem. s, lower surface not exhibiting laticiferLaticifer: A laticifer is a type of elongated secretory cell found in the leaves and/or stems of plants that produce latex and rubber as secondary metabolites. s, cross-veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s distinct; drying gray green above, pale yellowish brown below .. 📌Philodendron gardeniodorum
29B. Blades elongate or triangular, cordateCordate: or sagittateSagittate: at base, broadest at the base. Blades, sagittateSagittate: -lanceolateLanceolate: ; posteriorPosterior: lobes long, triangular or acute, primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s fewer than 12 pairs, arising at a 50-60 angle.
32A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s widely spaced; blades generally elongate, 25-74 cm long, 1.1-3.5 times as long as wide, 0.5-2 times as long as petiolePetiole: Leaf stem. ; drying dark brown or blackish .. 📌Philodendron jodavisianum
32B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s more closely spaced; blades broadly triangular, 21.5-29 cm long, 1.3-1.5 times as long as wide, 1.1-1.2 times as long as petiolePetiole: Leaf stem. ; drying dark brownish green above, medium brownish green below .. 📌Sterile species #9
28B. Blades hastateHastate: with lobes projecting sideways.
33A. Blades deeply hastateHastate: -lobed at the base, broadly triangular in shape, 28.3-39.5 cm long, 1.1-1.6 times longer than wide, 0.4-0.8 times as long as petiolePetiole: Leaf stem. , posteriorPosterior: lobes narrow and elongate, spreading at 95-115 angle, 11.5-24.5 cm long; drying dark gray-brown to greenish above, much paler and yellow-brown below .. 📌Philodendron fibraecataphyllum
33B. Blades triangular-elongate, cordateCordate: -sagittateSagittate: at the base, 24-63 cm long, 1.1-2.3 times longer than wide, 0.7-1.2 times longer than petiolePetiole: Leaf stem. , posteriorPosterior: lobes obtuse to rounded, 7.1-20.2 cm long, medial lobes lanceolateLanceolate: , proportionately much longer than in Philodendron fibraecataphyllCataphyll: A reduced, small leaf. Usually used to describe a modified leaf which lacks a blade and in appearance corresponds to a petiole sheath. um; primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s fewer and more widely spaced than in Philodendron fibraecataphyllCataphyll: A reduced, small leaf. Usually used to describe a modified leaf which lacks a blade and in appearance corresponds to a petiole sheath. um; drying conspicuously yellow-brown .. 📌Philodendron hebetatum
27B. Blades ovateOvate: , mostly deeply cordateCordate: but sometimes sagittateSagittate: or hastateHastate: .
34A. Older blades deeply cordateCordate: -sagittateSagittate: , younger blades ovateOvate: -lanceolateLanceolate: , attenuate or subcordateCordate: at the base, all blades widest near the base, 34-67 cm long, 1.2-2.6 times as long as wide, 1.0-1.6 times as long as petiolePetiole: Leaf stem. ; primarily lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s spaced more than 2 cm apart; internodes deeply fissured transversely, sap oozing like butterscotch, turning dark orange; drying dark green or brownish green .. 📌Philodendron delannayi
34B. All or most blades deeply cordateCordate: , sometimes sagittateSagittate: ; no striking dimorphism between older and younger blades; no obvious butterscotchcolored sap on stems.
35A. PetiolePetiole: Leaf stem. s with wings along their length.
36A. PetiolePetiole: Leaf stem. s with undulated wings along their length, not deeply sulcateSulcate: Furrowed; grooved. ; blades broadly ovateOvate: -cordateCordate: , broadest in basalBasal: Forming or belonging to a bottom layer or base. 1/3, 20-44 cm long, 1-1.3 times as long as wide, 0.8-1.4 times as long as petiolePetiole: Leaf stem. .. 📌Philodendron alatiundulatum
36B. PetiolePetiole: Leaf stem. s with straight marginal wings which are spreading then reflexed, deeply sulcateSulcate: Furrowed; grooved. ; blades deeply ovateOvate: -cordateCordate: , broadest at the base, 23-42 cm long, 1.1-1.6 times as long as wide, 0.8-1.2 times as long as petiolePetiole: Leaf stem. .. 📌Philodendron alatisulcatum
35B. PetiolePetiole: Leaf stem. s without wings along their length.
37A. Vining plant with long internodes, climbing high in trees; blades broadly ovateOvate: -cordateCordate: , 11-40 cm long, 1.2-1.9 times longer than wide and ca. 1.3 times longer than petiolePetiole: Leaf stem. , margins hyaline to pale yellowish, upper surface dark green, lower surface slightly paler, often purplish violet; basalBasal: Forming or belonging to a bottom layer or base. veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 4-5 pair, primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 2-6 pairs; drying gray-green to yellowgreen .. 📌Philodendron hederaceum
38A. Adult stems weakly sulcateSulcate: Furrowed; grooved. on living plants, moderately to conspicuously sulcateSulcate: Furrowed; grooved. and reddish brown upon drying, usually densely warty; spatheSpathe: A large sheathing bract enclosing the flower cluster. tube dark red to red-purple inside .. 📌Philodendron hederaceum var. kirkbridei
38B. Adult stems smooth, drying mostly green, weakly striate, never minutely warty; spatheSpathe: A large sheathing bract enclosing the flower cluster. tube green (sometimes weakly tinged reddish) inside .. 📌Philodendron hederaceum var. hederaceum
37B. Plants not extensively vining and climbing, and generally with shorter internodes and larger leaves.
39A. Plants very large, blades broadly ovateOvate: , deeply cordateCordate: at the base, widest near the base, 88-130 cm long, 1.1-1.3 times as long as wide, 0.7-0.9 times as long as petiolePetiole: Leaf stem. , posteriorPosterior: lobes 34-41 cm long, 28-38 cm wide, sinusSinus: rounded, 14-16 cm wide; drying dark brown or dark green .. 📌Philodendron magnum
39B. Not this combination of characters, plants of more moderate size.
40A. At least some of the primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s branching.
41A. Blades conspicuously bullate, ovateOvate: and deeply lobed at the base, widest near the middle, 17-43 cm long, 1.6-2 times as long as wide, 0.5-1.1 times as long as petiolePetiole: Leaf stem. , medium to dark green above, posteriorPosterior: lobes projecting inwards; primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 9-10 pairs, branching into an extensive network of cross-veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s, all veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s deeply sunken above; drying medium to light green .. 📌Philodendron lynnhannoniae
41B. Blades not conspicuously bullate; posteriorPosterior: lobes not projecting inwards; veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s not deeply sunken above; drying reddish brown to dark brown.
42A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 20-25 pairs, branching extensively; petiolePetiole: Leaf stem. s dark green and matte when young, soon reddish, verrucous and roughened to transversely wrinkled-ridged; blades ovateOvate: -sagittateSagittate: , widest near the middle, 46-85 cm long, 1.3-1.6 times as long as wide; drying reddish brown to dark brown .. 📌Philodendron rugapetiolatum
42B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 6-9 pairs, branching less extensively.
43A. Blades ovateOvate: , cordateCordate: or sometimes sagittateSagittate: , 25-62 cm long, 0.6-1.75 times as long as wide, drying reddish brown or dark brownish green; inflorescences 1 per axil; spatheSpathe: A large sheathing bract enclosing the flower cluster. blade cream outside, greenish white inside; spatheSpathe: A large sheathing bract enclosing the flower cluster. tube green outside, cherry-red inside .. 📌Philodendron brunneicaule
43B. Blades ovateOvate: , weakly cordateCordate: to sagittateSagittate: , 36-87 cm long, 1.3-1.6 times as long as wide, drying dark brown to dark yellow-brown; inflorescences 2-5 per axil; spatheSpathe: A large sheathing bract enclosing the flower cluster. blade white outside, reddish inside; spatheSpathe: A large sheathing bract enclosing the flower cluster. tube red-purple to dark reddish outside, red-purple to dark reddish inside .. 📌Philodendron dodsonii
40B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s usually not branching.
44A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s spaced at least 2 cm apart.
45A. Interprimary veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s clearly visible (effectively halving the distance between the primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s).
46A. Blades ovateOvate: -sagittateSagittate: , widest at the base.
47A. Upper leaf surface densely short-pale-lineate, posteriorPosterior: rib naked less than 1/3 its length; drying grayish brown above, grayish yellow-brown below .. 📌Philodendron delgadoi
47B. Upper surface lacking short pale lineations, posteriorPosterior: rib more prominently naked; drying dark brown .. 📌Philodendron subhastatum
46B. Blades broadly ovateOvate: , widest above the base.
48A. Blades deeply cordateCordate: , midrib and base of primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s thick.
49A. Midrib broadly sunken, much paler (yellowish white) above, sometimes tinged reddish or spotted with red, narrowly rounded, paler and purple-spotted below; blades broadly ovateOvate: -cordateCordate: , 1.1-1.5 times as long as wide, widest in lower half; drying light to medium brown .. 📌Philodendron ovatoluteum
49B. Midrib flat and paler yellow above, narrowly rounded, paler and tinged purplish violet below; blades narrowly ovateOvate: -sagittateSagittate: -cordateCordate: , 1.2-1.7 times as long as wide, widest near the middle; drying greenish brown to yellowish brown above, reddish brown below .. 📌Philodendron quelalii
48B. Blades not as deeply cordateCordate: ; midrib and base of primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s thinner, concolorous or only slightly paler above.
50A. BasalBasal: Forming or belonging to a bottom layer or base. veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s all free to the base.
51A. Blades ovateOvate: -cordateCordate: , widest below the middle, dark green and weakly glossy above, moderately paler and semiglossy below; drying medium brown above, light brown below .. 📌Sterile species #4
51B. Blades ovateOvate: -ellipticElliptic: and slightly cordateCordate: , widest near the middle, dark green with sublustrous sheen above, much paler and glossy below; drying dark green above, greenish brown below .. 📌Sterile species #6
50B. Lowest basalBasal: Forming or belonging to a bottom layer or base. veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s merged at the base into a short posteriorPosterior: rib.
52A. Blades cordateCordate: -subsagittateSagittate: , with a narrower sinusSinus: ; stems drying gray-brown and weakly and irregularly folded; petiolePetiole: Leaf stem. s drying more flattened and broader, two pairs of basalBasal: Forming or belonging to a bottom layer or base. veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s free to the base with a longer posteriorPosterior: rib; drying dark olive-green above, yellowgreen below .. 📌Sterile species #2
52B. Blades cordateCordate: , with a broader sinusSinus: ; stems drying dark brown and closely ribbed and glossy; petiolePetiole: Leaf stem. s drying more tereteTerete: Cylindrical or slightly tapering, and without substantial furrows or ridges. and more slender; only one pair of basalBasal: Forming or belonging to a bottom layer or base. veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s free to the base with a shorter posteriorPosterior: rib; drying moderately dark gray-brown above, paler gray-brown below .. 📌Sterile species #8
45B. Interprimary veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s not clearly visible.
53A. CataphyllCataphyll: A reduced, small leaf. Usually used to describe a modified leaf which lacks a blade and in appearance corresponds to a petiole sheath. s marcescentMarcescent: Withering but remaining attached to the stem. , the basalBasal: Forming or belonging to a bottom layer or base. part persisting brown and intact; blades narrowly ovateOvate: -ellipticElliptic: , deeply cordateCordate: , widest in lower half, 88-105 cm long, 1.8-2.6 times as long as wide, 0.8-1.1 times as long as petiolePetiole: Leaf stem. s; drying dark brown to dark reddish brown .. 📌Philodendron esmeraldense
53B. CataphyllCataphyll: A reduced, small leaf. Usually used to describe a modified leaf which lacks a blade and in appearance corresponds to a petiole sheath. s persisting as fibers, blades less than 1.8 times as long as wide.
54A. Base of cataphyllCataphyll: A reduced, small leaf. Usually used to describe a modified leaf which lacks a blade and in appearance corresponds to a petiole sheath. s persisting somewhat intact, upper part reduced to loose fibers, blades ovateOvate: and deeply cordateCordate: with elongated sinusSinus: , widest just above petiolePetiole: Leaf stem. attachment, 1.6 times as long as wide; drying dark brown above, medium brown below .. 📌Sterile species #7
54B. CataphyllCataphyll: A reduced, small leaf. Usually used to describe a modified leaf which lacks a blade and in appearance corresponds to a petiole sheath. s persisting entirely as fibers.
55A. CataphyllCataphyll: A reduced, small leaf. Usually used to describe a modified leaf which lacks a blade and in appearance corresponds to a petiole sheath. s persisting as a dense mass of pale fibers; blades ovateOvate: -sagittateSagittate: with short sinusSinus: , widest near the middle, 34-62 cm long, 22-46 cm wide, 1.3-1.6 times as long as than wide; drying dark brown or dark greenish brown .. 📌Philodendron pogonocaule
55B. CataphyllCataphyll: A reduced, small leaf. Usually used to describe a modified leaf which lacks a blade and in appearance corresponds to a petiole sheath. s persisting as loose fibers, blades ovateOvate: to ovateOvate: -triangular, deeply cordateCordate: -sagittateSagittate: with widely open sinusSinus: , widest near the base, 21-59 cm long, 1.1-1.7 times as long as wide; drying light green or medium brown .. 📌Philodendron fragrantissimum
44B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s spaced less than 2 cm apart.
56A. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 11-18 pairs.
57A. Blades broadly ovateOvate: and deeply cordateCordate: , 42-109 cm long, 1-1.9 times as long as wide, 0.56-1.05 times as long as petiolePetiole: Leaf stem. s; drying dark brown with primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s often turning black .. 📌Philodendron melanoneuron
57B. Blades not shaped as above or of that size, drying medium brown or green.
58A. PetiolePetiole: Leaf stem. s obtusely flattened adaxially; blades deeply ovateOvate: cordateCordate: , widest at the base, 45-78 cm long, 1.3-1.6 times as long as wide, 0.8-1.0 times as long as petiolePetiole: Leaf stem. ; inflorescences 7-11 per axil, spatheSpathe: A large sheathing bract enclosing the flower cluster. 5-6 cm long; drying medium brown .. 📌Philodendron parvidactylum
58B. PetiolePetiole: Leaf stem. s D-shaped; blades broadly ovateOvate: -cordateCordate: , widest at or near the middle, 20-50 cm long, 0.9-1.7 times longer than wide, 0.5-0.9 times as long as the petiolePetiole: Leaf stem. ; inflorescences 2-4 per axil, spatheSpathe: A large sheathing bract enclosing the flower cluster. 6.5-12 cm long; drying medium brown to greenish brown .. 📌Philodendron grandipes
56B. Primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s generally fewer than 11 pairs (but see P. tenue).
59A. Blades generally ovateOvate: -triangular and broadest near the base (sometimes ovateOvate: -lanceolateLanceolate: in Philodendron tenue), hastateHastate: -cordateCordate: .
60A. SinusSinus: V-shaped, acute to almost obtuse, sometimes closed; blades ovateOvate: -triangular to ovateOvate: -lanceolateLanceolate: , 31-78 cm long, 1.2-3.1 times as long as wide, 0.6-1.4 times as long as petiolePetiole: Leaf stem. ; primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 8-14 pairs; drying pale green or brown .. 📌Philodendron tenue
60B. SinusSinus: U-shaped, broadly open; blades ovateOvate: -triangular, 16-21 cm long, 9-12 cm wide, 1.7-1.8 times as long as wide, ca. 0.7 times as long as petiolePetiole: Leaf stem. ; primary lateral veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s 6 pairs; drying dark green above, reddish brown below .. 📌Sterile species #3
59B. Blades ovateOvate: -cordateCordate: (sometimes somewhat ovateOvate: -triangular in Philodendron sparreorum, but then sinusSinus: hippocrepiform with posteriorPosterior: lobes projecting inwards).
61A. SinusSinus: U-shaped, without a well-developed posteriorPosterior: rib present (basalBasal: Forming or belonging to a bottom layer or base. veinVein: Venation types: A. midrib; B. primary lateral veins; C. interprimaray veins; D. secondary veins; E. collective veins; F. tertiary veins; G. basal ribs; H. basal veins. s all free to the base); blades not deeply cordateCordate: , with small posteriorPosterior: lobes, 17-30 cm long, 1.3-1.7 times as long as wide; drying dark green above, medium brown below .. 📌Sterile species #5
61B. SinusSinus: generally hippocrepiform (sometimes U-shaped), with a well-developed posteriorPosterior: rib present; blades deeply cordateCordate: , with extensive posteriorPosterior: lobes often projecting inwards.
62A. Blades 0.8-1.3 times as long as wide, broadly ovateOvate: cordateCordate: .
63A. CataphyllCataphyll: A reduced, small leaf. Usually used to describe a modified leaf which lacks a blade and in appearance corresponds to a petiole sheath. s reddish, persisting intact at upper nodes, turning dark brown, ultimately semi-intact with an underlayment of reddish brown to light brown fibers; blades ovateOvate: to broadly ovateOvate: , prominently lobed at base, broadest at the point of petiolePetiole: Leaf stem. attachment or slightly above; drying medium to dark brown .. 📌Philodendron roseocataphyllum
63B. CataphyllCataphyll: A reduced, small leaf. Usually used to describe a modified leaf which lacks a blade and in appearance corresponds to a petiole sheath. s pale green, turning yellowish and persisting semi-intact at upper nodes; blades ovateOvate: cordateCordate: , sometimes sagittateSagittate: at base, broadest near the middle; drying green or light brown .. 📌Philodendron strictum
62B. Blades 1.2-1.6 times as long as wide, narrowly ovateOvate: cordateCordate: to ovateOvate: -triangular, widest near the base, drying light grayish green to gray or dark yellow-brown above, light yellowish brown below .. 📌Philodendron sparreorum
 


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