Key to Species of Philodendron Subgenus Pteromischum


Based on Croat, Delanny, Duncan and Kostelac, 2015
( extracted from Grayum, M. H. 1996 )

Click on 📌 to highlight and compare characteristics.
Click on the line numbers to select characteristics.



1A. Plants generally appressed-climbing and with adventitious roots at most nodes; stem epidermis drying yellowish to brownish, brittle, and coarsely sulcateSulcate: Furrowed; grooved. , or else green and finely striate; unsheathed portion of petiolePetiole: Leaf stem. frequently more than 2.0 cm long; inflorescences (1)2(3), typically borne close to supporting trunk; 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 typically present; pedunclePeduncle: Flower stem. usually more than 1/3 as long as spadixSpadix: A spike of minute flowers closely arranged around a fleshy axis and typically enclosed in a spathe. .. 📌Philodendron subg. Pteromischum sect. Pteromischum
2A. Stems becoming lead-colored to brown, tan or stramineous in age, drying stramineous to yellowish brown and (usually) coarsely sulcateSulcate: Furrowed; grooved. .
3A. Blade 34.6-82.8 cm long, 3.7-5.4 times as long as wide, narrowly to broadly lanceolateLanceolate: or ellipticElliptic: al; 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 13-22 pairs; spatheSpathe: A large sheathing bract enclosing the flower cluster. becoming bright orange externally in fruit .. 📌Philodendron senatocarpium
3B. Blade 11.7-45.9 cm long, 1.1-3.6 times as long as wide, ovateOvate: to lanceolateLanceolate: ; 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 4-19 pairs (if more than 12, blade less than 2.5 times as long as wide); spatheSpathe: A large sheathing bract enclosing the flower cluster. green or greenish to pale yellowish in fruit.
4A. PetiolePetiole: Leaf stem. sheath involuteInvolute: In involute vernation both margins on opposing sides of the leaf are rolled up forming two tubes that meet at the midrib of the leaf. to erect or erect-spreading for most of its length, pressing flat in lateral plane .. 📌Philodendron opacum
4B. PetiolePetiole: Leaf stem. sheath horizontally spreading to revolute for most of its length, pressing flat in dorsiventral plane .. 📌Philodendron sulcatum
2B. Stems remaining green, drying bright green and (usually) finely striate.
5A. PetiolePetiole: Leaf stem. 13.5-42.2 cm long; blade 24.6-56.2 cm long .. 📌Philodendron rhodoaxis subsp. lewisii
5B. PetiolePetiole: Leaf stem. 7.4-18.8 cm long; blade 12.0-28.8 cm long.
6A. PetiolePetiole: Leaf stem. 7.4-10.5 cm long, the unsheathed portion less than 0.5 cm long; blade 10.7-19.9 cm long; spadixSpadix: A spike of minute flowers closely arranged around a fleshy axis and typically enclosed in a spathe. 8.4-12.2 cm long, usually with evident distal sterile zone .. 📌Philodendron herbaceum
6B. PetiolePetiole: Leaf stem. 11.3-16.6 cm long, the unsheathed portion 0.0-4.1 cm long; blade 18.2-28.8 cm long; spadixSpadix: A spike of minute flowers closely arranged around a fleshy axis and typically enclosed in a spathe. 5.7-9.2 cm long, with or without distal sterile region .. 📌Philodendron hooveri
1B. Plants typically widely branched and shrubby, lacking adventitious nodal roots on flowering branches; stem epidermis drying yellowish to dark brown (never green), finely to coarsely sulcateSulcate: Furrowed; grooved. , not markedly cracking and brittle; unsheathed portion of petiolePetiole: Leaf stem. rarely more than 2.0 cm long; inflorescences usually solitary (except Philodendron inaequilaterum), typically borne well away from supporting tree on divergent or pendulous branches; 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 rarely present; pedunclePeduncle: Flower stem. usually less than as long as spadixSpadix: A spike of minute flowers closely arranged around a fleshy axis and typically enclosed in a spathe. .. 📌Philodendron subg. Pteromischum sect. Fruticosa
7A. PetiolePetiole: Leaf stem. sheaths generally involuteInvolute: In involute vernation both margins on opposing sides of the leaf are rolled up forming two tubes that meet at the midrib of the leaf. to erect-spreading; inflorescences frequently paired; ripe fruits bright orange; seeds in life white .. 📌Philodendron inaequilaterum
7B. PetiolePetiole: Leaf stem. sheaths involuteInvolute: In involute vernation both margins on opposing sides of the leaf are rolled up forming two tubes that meet at the midrib of the leaf. to horizontally splayed; inflorescences mostly solitary, rarely paired (in Philodendron ichthyoderma and Philodendron alliodorum); ripe fruits whitish to ochroleucous; seeds typically reddish or purplish.
8A. PetiolePetiole: Leaf stem. sheath involuteInvolute: In involute vernation both margins on opposing sides of the leaf are rolled up forming two tubes that meet at the midrib of the leaf. to erect for most of its length (may be splayed distally), pressing flat in lateral plane.
9A. Epidermis of stems and petiolePetiole: Leaf stem. s not strongly modified; petiolePetiole: Leaf stem. 31-43% as long as blade; blade 13.4-32.2 cm long, 3.2-14.0 cm wide, with 10-14 pairs 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; spadixSpadix: A spike of minute flowers closely arranged around a fleshy axis and typically enclosed in a spathe. at anthesisAnthesis: The period during which pollen is presented and/or the stigma is receptive. 5.9-12.3 cm long; scandent epiphyteEpiphyte: A plant that grows harmlessly upon another plant and derives its moisture and nutrients from the air, rain, and sometimes from debris accumulating around it. s .. 📌Philodendron alliodorum
9B. Epidermis of stems and petiolePetiole: Leaf stem. s strongly modified, either transversely fissured and scaly or else yellowish brown, brittle, and glossy; petiolePetiole: Leaf stem. 42-66% as long as blade; blade 26.3-47.1 cm long, 11.0-24.0 cm wide, with 15-25 pairs 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; spadixSpadix: A spike of minute flowers closely arranged around a fleshy axis and typically enclosed in a spathe. at anthesisAnthesis: The period during which pollen is presented and/or the stigma is receptive. 9.9-17.4 cm long; terrestrial plants or scandent epiphyteEpiphyte: A plant that grows harmlessly upon another plant and derives its moisture and nutrients from the air, rain, and sometimes from debris accumulating around it. s.
10A. Terrestrial plants, clambering in understory vegetation; epidermis of stems and petiolePetiole: Leaf stem. s becoming coarsely transversely fissured and scaly; blade 14.4-24.0 cm wide, 1.6-2.6 times as long as wide; 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 15-22 pairs; pedunclePeduncle: Flower stem. 2.8-5.1 cm long .. 📌Philodendron ichthyoderma
10B. Scandent epiphyteEpiphyte: A plant that grows harmlessly upon another plant and derives its moisture and nutrients from the air, rain, and sometimes from debris accumulating around it. s on tree trunks; epidermis of stems and petiolePetiole: Leaf stem. s becoming yellowish brown, brittle, and glossy; blade 11.0-16.9 cm wide, 2.04-2.43 times as long as wide; 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; pedunclePeduncle: Flower stem. 2.0-3.0 cm long .. 📌Philodendron rodrigueziae
8B. PetiolePetiole: Leaf stem. sheath broadly to horizontally splayed for most of its length, pressing flat in dorsiventral plane .. 📌Philodendron tuerckheimii
 


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