Research Article |
Corresponding author: Cassia Mônica Sakuragui ( cmsakura12@gmail.com ) Academic editor: Peter Boyce
© 2018 Cassia Mônica Sakuragui, Luana Silva Braucks Calazans, Leticia Loss de Oliveira, Érica Barroso de Morais, Ana Maria Benko-Iseppon, Santelmo Vasconcelos, Carlos Eduardo Guerra Schrago, Simon Joseph Mayo.
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Citation:
Sakuragui CM, Calazans LSB, de Oliveira LL, de Morais EB, Benko-Iseppon AM, Vasconcelos S, Schrago CEG, Joseph Mayo SJ (2018) Recognition of the genus Thaumatophyllum Schott − formerly Philodendron subg. Meconostigma (Araceae) − based on molecular and morphological evidence. PhytoKeys 98: 51-71. https://doi.org/10.3897/phytokeys.98.25044
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Philodendron subgenus Meconostigma has been a well-circumscribed group since 1829. Members of this group are easily distinguished by diagnostic morphological characters as well as by a distinct ecology and geographical distribution. Based on molecular, morphological and cytological evidence, we propose the recognition of P. subg. Meconostigma as a distinct genus, Thaumatophyllum Schott. We also present the necessary new combinations, an emended key and some nomenclatural and taxonomic corrections regarding 21 names of Thaumatophyllum.
chromosomes, molecular phylogeny, morphology, nomenclature, Philodendron , Thaumatophyllum
Philodendron Schott is the second most species-rich and diverse genus in the family Araceae and also in the “Homalomena clade” (sensu
The evolutionary history of the “Philodendron clade” has been discussed in several recent papers (
The recent recognition of the genus Adelonema for the American species of Homalomena (
Philodendron subgenus Meconostigma (= Thaumatophyllum) has been a well-circumscribed group since the genus Philodendron was first recognised taxonomically by
Based on the evidence now accumulated (most recently, by
We have sampled data for 110 extant species of Philodendron, 21 species of Thaumatophyllum and six species of Homalomena and five of Adelonema of the nuclear 18S and external transcribed spacer (ETS) and the chloroplast trnK intron, maturase K (matK) genes, trnL intron, trnL-trnF intergenic spacer. Species from the genera Cercestis, Culcasia, Colocasia, Dieffenbachia, Heteropsis, Montrichardia, Nephthytis, Furtadoa and Urospatha were included as the outgroup. The species list, the voucher and GenBank accession numbers are listed in Suppl. material
Additionally, we generated a subsampled dataset comprised of species from our original data with available ETS and 18S sequences and at least two available chloroplast sequences. This strategy aimed to reduce the impact of missing data in the concatenated analysis. This taxon sampling is described in Suppl. material
The methodological approach of
We have also performed phylogenetic analysis for concatenated chloroplast markers separated from nuclear markers from the subsample consisting of species with available ETS and 18S sequences and at least two chloroplast markers in order to compare the estimated trees. Both chloroplast and nuclear datasets were used to estimate trees from Maximum Likelihood and Bayesian analysis approaches.
A maximum likelihood approach was performed in PhyML, implemented in Seaview (
The Bayesian analysis were performed in MrBayes 3.2.2 (
As observed in Figure
The subsampled chloroplast analyses (Figure
Molecular evidence.
Similarly,
The analysis conducted by
These results are consistent with our findings that Thaumatophyllum is a monophyletic and isolated lineage in Philodendron, the sister group of P. subg. Pteromischum and P. subg. Philodendron.
Morphological evidence. As here defined, Thaumatophyllum is a Neotropical genus composed of 21 species. It is defined by an arborescent habit, very much thickened spathe, well developed sterile intermediate zone in the inflorescence equal or longer than the staminate zone, the gynoecium always having stylar lobes and an axial vascular system independent of the funicle supply (
Shoot morphology and arborescent habit. Stem architecture in Thaumatophyllum is similar to Philodendron, since the mature stems of both genera are sympodia composed of diphyllous articles (terminology after
Inflorescence. Thaumatophyllum is characterised by normally solitary inflorescences in each floral sympodium and very thick, weakly constricted or unconstricted spathes with a uniformly white inner surface. In the spadix, the long staminodial zone that equals or exceeds the fertile male zone is the most useful diagnostic character and distinguishes it from the genus Philodendron. This long staminodial zone plays an important role in the floral biology, serving as a food resource and as the main source of the very large temperature elevations observed during flowering (
Pistillate flowers and the Gynoecium. Unlike Philodendron, the style lobes are conspicuous in Thaumatophyllum and, together, constitute the style crown (
Based on molecular evidence,
Chromosome numbers. Available chromosome numbers for Philodendron range from 2n = 28 to 40 (
Evolutionary history.
Ecology. Thaumatophyllum species have a preference for open environments with higher light intensity. The life forms vary from terrestrial to hemi-epiphytic, but can be rupicolous (T. saxicola and T. adamantinum), aquatic or subaquatic in freshwater swamps at lowland sites (T. tweedieanum, T. undulatum, T. uliginosum). More frequent are forest hemi-epiphytes which grow equally well in rupicolous habitats or even in open coastal sites on sand in the case of the T. williamsii, T. corcovadense, T. bipinnatifidum and T. speciosum. All the extant species have a notable preference for open habitats and the ability to tolerate a certain degree of drought.
Thaumatophyllum spruceanum Schott, Bonplandia 7: 31. 1859.
from Ancient Greek “θαυματ-” (“thaumato-”, wonder, miracle) + “φύλλον” (“phyllum”, leaf); wonderful leaf, referring to the beautiful and peculiar leaves of the type species.
Philodendron adamantinum Schott, Syn. Aroid. 114. 1856.
Brazil, Minas Gerais, Tejuco, Serro Frio, Martius 1208 (holotype: M).
Philodendron bipinnatifidum Schott ex Endl., Gen. Pl. 1(3): 237. 1837.
Type. Illustration in Schott Icones Aroideae Nº 2640 (lectotype, designated by
Philodendron selloum C.Koch, Index Seminum (B) 1853 (App.): 14. 1853.
Type. Plant cultivated at Berlin Botanic Garden, C. Koch s.n. (lectotype, designated by
Philodendron pygmaeum Chodat & Vischer, Bull. Soc. Bot. Genève 11: 299. 1919 publ. 1920.
Type. Paraguay, Paraguari, ‘Cerro Akahay’, 1914, R.H. Chodat & W. Vischer 358 (holotype: G).
Philodendron brasiliense Engl., Fl. Bras. 3(2): 168. 1878.
Type. Brazil, Minas Gerais, Caldas, Rio Verde, Feb-Mar. 1868, S.E. Henschen in Herb. Regnell III. Nº 1292 (lectotype, designated by
Philodendron cymbispathum Engl., Bot. Jahrb. 26: 555. 1899.
Type. Brazil, Minas Gerais, A.F.M. Glaziou 16497 (lectotype, designated here: B; isolectotypes: C, LE, P).
Philodendron corcovadense Kunth, Enum. Pl. 3: 49. 1841.
Type. illustration in Vellozo, Fl. Flum. 9: tab. 115. 1831 (lectotype, designated by
Philodendron melanorrhizum Reitz, Sellowia 9:50, t.10. 1958.
Type. Brazil, Santa Catarina, Itajaí, Luís Alves, Braço Joaquim, 14 Oct. 1954, R. Klein 917 (holotype: HBR; isotypes: NY, UC, US).
Philodendron dardanianum Mayo, Kew Bull. 46: 648. 1991.
Type. Brazil, Bahia, Chapadão Oriental da Bahia, 37km N from Correntina from road to Inhaúmas, 29 Apr. 1980, Harley et al. 21963 (holotype: CEPEC; isotypes: K, MO, US).
Philodendron leal-costae Mayo & G.M. Barroso, Aroideana 2: 82. 1979.
Type. Brazil, Bahia, Serra do Jatobá, Nossa Senhora dos Milagres, Morro do Couro, 06 Mar. 1977, Harley et al. 19428 (holotype: CEPEC; isotypes: K, M, MO, NY, P, RB, SEL, US).
Philodendron lundii Warm., Vidensk. Meddel. Naturhist. Foren. Kjøbenhavn 1867: 128. 1867.
Type. Brazil, Minas Gerais, Lagoa Santa, Warming s.n. (holotype: C).
Philodendron mello-barretoanum Burle-Marx ex G.M. Barroso, Arch. Jard. Bot. Rio de Janeiro 15: 94. 1957.
Type. Brazil, Goiás, cultivated at Jardim Botânico do Rio de Janeiro, Burle-Marx s.n. (holotype: RB 97081).
Philodendron paludicola E.G. Gonç. & Salviani, Aroideana 25: 2. 2002 publ. 2003.
Type. Brazil, Espírito Santo, São Mateus, access to Barra Nova, 21 Dec. 2000, E.R. Salviani & L. Bernacci 1869 (holotype: UB; isotype: K).
Philodendron petraeum Chodat & Vischer, Bull. Soc. Bot. Genève 11: 296. 1919 publ. 1920.
Type. Paraguay, Tobaty between Tobaty and Barrero Grande, R.H. Chodat & W. Vischer 349 (holotype: G).
Philodendron petraeum var. triangulare Chodat & Vischer, Bull. Soc. Bot. Genève 11: 299. 1919 publ. 1920.
Type. Paraguay, Tobaty between Tobaty and Barrero Grande, R.H. Chodat & W. Vischer 347 (holotype: G).
Philodendron petraeum var. valenzuelae Chodat & Vischer, Bull. Soc. Bot. Genève 11: 299. 1919 publ. 1920.
Type. Paraguay, prope Valenzuela, R. H. Chodat & W. Vischer 357 (holotype: G).
The species was previously synonymised under P. tweedieanum (= T. tweedieanum) by
Philodendron saxicola Krause, Pflanzenr. IV, 23Db: 133. 1913.
Type. Brazil, Bahia, Serra do Sincorá, Nov. 1906, E. Ule 7568 (holotype: B; isotype L).
Philodendron solimoesense A.C. Smith, J. Arnold Arbor. 20: 289. 1939.
Type. Brazil, Amazonas, São Paulo de Olivença, basin of Creek Belem, Oct-Dec. 1936, B.A. Krukoff 8861 (holotype: NY; isotype: F).
Philodendron speciosum Schott ex Endl., Gen. Pl. 1(3): 237. 1837.
Type. illustration in Schott Icones Aroideae N° 2522 (lectotype, designated by
Philodendron spruceanum (Schott) G.M. Barroso, Arch. Jard. Bot. Rio de Janeiro 17: 14. 1962, nom. illeg.
Type. based on Thaumatophyllum spruceanum Schott.
Philodendron goeldii G.M. Barroso, Arch. Jard. Bot. Rio de Janeiro 15: 95. 1957.
Type. Brazil, Manaus, Igarapé das Flores, 30 Sept. 1903, A. Goeldi s.n. (holotype: MG 3879).
Brazil, inundated forest in angle between Rio Negro and Solimões, 1851, Spruce 120 (holotype: K).
Philodendron stenolobum E.G. Gonç., Aroideana 25: 3. 2002 publ. 2003.
Type. Brazil, Espírito Santo, Colatina, road to São Domingos, 10 Oct. 2000, E.G. Gonçalves et al. 567 (holotype: UB).
Philodendron tweedieanum Schott, Bonplandia (Hannover) 7: 29. 1859.
Type. Argentina, Entre Rios, delta region of Rio Paraná, J. Tweedie s.n. (lectotype, designated here: K; isolectotype: LE).
Philodendron dubium Chodat & Vischer, Bull. Soc. Bot. Genève 11: 295. 1919 publ. 1920.
Type. Paraguay, prope San Bernardino, E. Hassler 1713 (lectotype, designated here: G); Paraguay, Lago Ypacaraí, R.H. Chodat & W. Vischer 359 (remaining syntype: G, not found).
Philodendron uliginosum Mayo, Kew Bull. 46: 666. 1991.
Type. Brazil, Minas Gerais, Santana do Riacho, 25 Oct. 1974, G. Hatschbach & Koszicki 35350 (holotype: MBM; isotypes K, US).
Philodendron undulatum Engl., Monogr. Phan. 2: 428. 1879.
Type. Paraguay, Aregua plains, Jul. 1875, B. Balansa 576 (lectotype, designated here: P; isolectotype: G, not found).
Philodendron eichleri Engl., Bot. Jahrb. Syst. 26: 556. 1899.
Type. Brazil, Minas Gerais, Carandaí, 15 Nov. 1887, A.F.M. Glaziou 17332 (lectotype, designated by
Philodendron petraeum var. tobatiense Chodat & Vischer, Bull. Soc. Bot. Genève 11: 297. 1919 publ. 1920.
Type. Paraguay, Cerro Tobaty, R.H. Chodat & W. Vischer 350 (holotype: G).
Philodendron venezuelense Bunting, Acta Bot. Venez. 10: 315. 1975.
Type. Venezuela, Territorio Federal Amazonas, Departamento Casiquiare, environs of Yavita on the Temi and near the Yavita-Pimichín road, 6-19 Jul. 1969, Bunting et al. 3864 (holotype: MY; isotypes: NY, U).
Philodendron williamsii J.D. Hooker, Bot. Mag. 97: t. 5899. 1871.
Type. Brazil, Bahia, region of Salvador, cultivated at Kew, Aug. 1870, Williams s.n. (holotype: K).
Philodendron xanadu Croat, Mayo & J. Boos, Aroideana 25: 63. 2002 publ. 2003.
Type. origin unknown, based on plant cultivated in Wellington, West Palm Beach, Florida, T.B. Croat 81537 (holotype: K; isotypes: B, F, COL, GH, INPA, K, MO, NY, R, RSA, SP, TRIN, UB, US).
(adapted from
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 |
We are grateful to Marco Octávio Pellegrini for the illustration, Rodrigo Theófilo Valadares for supporting with images compositions, Geziel Aguilar for providing images of types at Copenhagen herbarium, Laurent Gautier for providing images of types at Geneva herbarium, and Eduardo Gomes Gonçalves and Leland Mayano for T. petraeum and T. xanadu fresh material, respectively. We also would like to thank the CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) for the research fellowships to CMS and CEGS and for the scholarships to LL-O, LSBC and EBM.
Taxon sampling, voucher information and GenBank