Epiphyte or terrestrial; stems ca. 1.5 cm thick, to 30 cm long; roots numerous, moderately thin; cataphylls 10-15 cm long, drying tan, persisting intact.

LEAVES with petioles ± erect, subterete, obscurely sulcate, 19-60 cm long, 6-9 mm diam.; geniculum ca. 2 cm long; blades ovate, moderately thick, 15-46 cm long, 9.5-28 cm wide, gradually to abruptly acuminate at apex, deeply lobed at base; anterior lobe 21-33 cm long, the margins convex; posterior lobes 9-16 cm long; sinus spathulate, rounded at apex; both surfaces matte; midrib convexly raised at base above, narrowing and acute at apex, raised below; primary lateral veins 3-6 per side, departing midrib at 45° angle, raised above and below; lesser veins sunken above, raised below; basal veins ca. 8 pairs, 3-4 coalesced 2.5-4 cm; posterior ribs naked, turned up along the outer margin; collective vein arising from one of the lowermost basal veins, extending to apex, 3-7 mm from margin.

INFLORESCENCE spreading, shorter than leaves; peduncle (7)15-43 cm long, shorter than petioles; spathe oblong-elliptic, pale green to white, 7-11.5 cm long, 2.3-2.7 cm wide, long-acuminate at apex, obtuse at base; spadix cream to pale yellow-green, turning dark lavender to violet-purple, weakly tapered at apex, 4.5-7.6 cm long, 8-11 mm diam. at base, 5-7 mm diam. at apex; the flowers 4-lobed, ca. 3 mm long, ca. 4 mm wide, the sides jaggedly sigmoid; 5-10 flowers visible in the principal spiral, 8-9 flowers visible in the alternate spiral; tepals glossy, lateral tepals ca. 1.8 mm wide, the inner margin upturned; pistils raised, white to pale green; stigma brushlike, 0.4-1 mm long, glistening papillae exserted 4-5 days before first stamens emerge, turning brown; stamens emerging slowly from base, exserted on short white filaments, held over and obscuring pistil; anthers white, 0.3-0.5 mm long, 0.3-0.9 mm wide; thecae elipsoid, not divaricate; pollen white.

INFRUCTESCENCE with spadix to 15 cm long; berries red-vioJct. ovate, acute at apex; seeds not seen. Fig. 121.

Anthurium obtusilobum ranges from Costa Rica to Colombia (Choco) at elevations of 600 to 1,550 m in premontane wet, tropical wet, premontane rain, and lower montane wet forest. The species is in section Calomystrium and is closest to A. hoffmannii, sharing with that species thick, persistent, reddish-brown, entire cata-phylls and a similar inflorescence. It is readily separated from other members of the section by having the collective vein arising from one of the lowermost basal veins and continuing to the apex close to the margin.
 
 

Map of Mesoamerican specimens with coordinates

Costa Rica : 900 m, 10.20N 84.40W, 25 Jul 1986, William A. Haber ex E. Bello C., A. Clagget & M. Powell 5501 (MO).
Costa Rica : 900-1150 m, 10.18N 84.45W, 29 Oct 1986, William A. Haber ex Eric Bello C. 6156 (MO).
Costa Rica Alajuela: 1100 m, 10.10.30N 84.30.00W, 26 Sept. 1987, Thomas B. Croat 68057 (MO).
Costa Rica Alajuela: 900 m,, 10 julio 1985, William A. Haber & Eric Bello C. 1925 (MO).
Costa Rica Alajuela: 850 m, 10.18N 84.44W, 12 December 1987, William Haber & Erick Bello 7885 (MO).
Costa Rica Alajuela: W 1259 m, 10.04.46N 84.26.30W, 21 octubre 1986, Gerardo Herrera Ch. 92 (MO).
Costa Rica Alajuela: 600 m,, 11 Apr 1976, Utley 4607 (NY).
Costa Rica Alajuela: 950-1000 m, 10.19N 84.4W, 7 December 1989, Erick Bello 1568 (MO).
Costa Rica Alajuela: Bosque Eterno De Los Niños; Cordillera de Tilarán, 820 m, 10.21N 84.40W, 15 June 1991, Erick Bello & William Haber 2876 (CR).
Costa Rica Alajuela: Bosque Eterno De Los Niños; Cordillera de Tilarán, 820 m, 10.21N 84.40W, 15 June 1991, Erick Bello & William Haber 2882 (CR).
Costa Rica Alajuela: 925 m, 10.11N 84.30W, 3 September 1996, Thomas B. Croat 78845 (INB, MO).
Costa Rica Cartago: 1350 m, 09.47N 83.48W, 6 Aug 1984, Michael H. Grayum & Pam Sleeper 3693 (MO).
Costa Rica Cartago: 1330 m, 9.17N 83.50W, 26 February 1986, Scott Hoover 1344 (MO).
Costa Rica Cartago: 1200 m, 9.52N 83.35W, 26 September 1990, Helen Kennedy 4679 (MO, US).
Costa Rica Cartago: 1525-1595 m, 09.45S 83.47W, 7 September 1996, Thomas B. Croat 79040 (MO).
Costa Rica Guanacaste: 1000 m,, 17 Feb 1984, Khan et al. 1144A (BM).
Costa Rica Guanacaste: 1300 m, 10.25N 84.50W, 13 APR 1986, William A. Haber ex Eric Bello. C. & L. Lierheimer 4385 (MO).
Costa Rica Guanacaste: 1400 m,, 25 Jan. 1986, Christenson 1106 (MO).
Costa Rica Guanacaste: 1100 m, 10.46N 85.49W, 26 November 1987, Gerardo Herrera 1405 (MO).
Costa Rica Guanacaste: 1200 m, 10.46N 85.49W, 23 November 1987, Gerardo Herrera 1376 (MO).
Costa Rica Guanacaste: 600-800 m, 10.25N 84.46W, 9 MAY 1986, William A. Haber ex E. Bello C.,L. Lierheimer & B. Hammel 4810 (MO).
Costa Rica Guanacaste: 1300 m, 10.22N 84.51W, 4 September 1988, William Haber & Willow Zuchowski 8687 (MO).
Costa Rica Guanacaste: 900-1200 m, 10.47N 85.18W, 27-28 Jan 1983, G. Davidse et al. 23446 (MO).
Costa Rica Guanacaste: P.N. Guanacaste; Cordillera de Guanacaste, 1100 m, 10.54.42N 85.27.58W, 17 June 1995, J.F. Morales 4670 (CR).
Costa Rica Heredia: 700-800 m, 10.17.30N 84.04.30W, 3 April 1986, Michael H. Grayum 6700 (MO).
Costa Rica Heredia: 300-400 m, 10.22N 84.03W, 22 July 1984, Michael H. Grayum & Brian Jacobs 3582 (MO).
Costa Rica Heredia: 425 m, 10.20N 84.03W, March, 1987, B.A. Loiselle 295 (MO).
Costa Rica Lim—n: Canton de Guapiles, 1300 m, 10.06.20N 83.50.40W, 23 February 1990, Abelardo Chacón & G. Herrera 767 (CR, MO).
Costa Rica Lim—n: 850 m, 9.47.40N 83.06.30W, 8 April 1989, Rafael Robles & Abelardo Chacón 2710 (MO).
Costa Rica Lim—n: 850 m, 9.47.40N 83.06.30W, 11 April 1989, Rafael Robles & Abelardo Chacón 2743 (MO).
Costa Rica Lim—n: 850 m, 9.47.40N 83.06.30W, 11 April 1989, Rafael Robles & Abelardo Chacón 2750 (MO).
Costa Rica Lim—n: 500 m, 10.09N 83.56W, 16 May 1988, Gina Umaña 222 (MO).
Costa Rica Lim—n: 500 m, 10.09N 83.56W, 16 May 1988, Gina Umaña 227 (MO).
Costa Rica Lim—n: Cordillera de Talamanca, 850 m, 09.47.40N 83.06.30W, 11 Apr 1989, Robles & Chacon 2749 (CM, CR, MO).
Costa Rica Puntarenas: 1600 m, 10.18N 84.48W, 19 Aug 1984, Michael H. Grayum & Pam Sleeper 3869 (MO).
Costa Rica Puntarenas: Monteverde Reserve, 1500-1550 m, 10.18N 84.48W, 5 Nov 1992, Ingram & Ferrell-Ingram 1669 (SEL).
Costa Rica Puntarenas: Monteverde Reserve, 1500-1550 m, 10.18N 84.48W, 15 Apr 1993, Ingram & Ferrell-Ingram 1818 (SEL).
Costa Rica Puntarenas: 1500 m, 10.20N 84.50W, 30 Nov. 1985, William A. Haber ex Eric Bello 3662 (MO).
Costa Rica Puntarenas: 1500-1620 m,, 24 Oct. 1984, Willow Z. Pounds 335 (MO).
Costa Rica Puntarenas: 1000-1200 m, 10.16N 84.48W, 18 Jun 1985, B. Hammel & W. Haber 13926 (MO).
Costa Rica Puntarenas: Cordillera de Tilarán, 1100 m, 10.16.33N 84.47.45W, 17 December 1992, Zobeida Fuentes, M. Chavarría & J. Jiménez 64 (CR).
Costa Rica Puntarenas: Cordillera de Tilarán, 1100-1200 m, 10.16.33N 84.47.45W, 6 January 1993, Zobeida Fuentes 90 (CR).
Costa Rica San José: 1100-1200 m, 10.04N 83.58W, 23 Jan 1983, G. Davidse et al. 23191 (MO).
Costa Rica San José: P.N. Braulio Carrillo, 300-600 m,, , Todzia 1245 (TEX).
Panama Bocas del Toro: 1200 m, 8.44N 82.17W, 11 March 198, T.B. Croat & M.H. Grayum 60342 (MO).
Panama Bocas del Toro: 850 m, 08.48N 82.13W, 29 March 1993, Thomas B. Croat 74923 (MO).
Panama Bocas del Toro: 670 m, 8.35N 82.19W, 18 February 1986, Scott Hoover 1331 (MO).
Panama Bocas del Toro: 650-700 m, 08.45N 82.15W, 29 June 1987, Gordon McPherson 11128 (MO).
Panama Bocas del Toro: 700 m, 8.45N 82.15W, 12 Feb. 1986, Gordon McPherson 8425 (MO).
Panama Bocas del Toro: 950-1100 m, 8.48N 82.10W, 7 March 1986, Gordon McPherson 8654 (MO).
Panama Bocas del Toro: 850-950 m, 8.45N 82.15W, 25 June 1986, Gordon McPherson 9654 (MO).
Panama Bocas del Toro: 1000 m, 8.48N 82.12W, 5 Feb. 1984, H.W. Churchill, G. de Nevers & H. Stockwell 4641 (MO).
Panama Chiriquí: 1300 m, 8.43N 82.14W, 23 Feb. 1985, Hampshire & Whitefoord 31 (BM).
Panama Chiriquí: 1100-1135 m, 8.43N 82.17W, 8 March 1985, T.B. Croat & M.H. Grayum 60068 (MO).
Panama Chiriquí: 1200-1300 m, 8.45N 82.18W, 20 June 1987, Thomas B. Croat 66541 (MO).
Panama Chiriquí: 1100 m, 8.45N 82.15W, 27 April 1986, Gordon McPherson 9075 (MO).
Panama Chiriquí: 1050 m, 08.45N 82.15W, 17 April 1987, Gordon McPherson 10877 (MO).
Panama Chiriquí: 1100 m, 8.45N 82.13W, 8 Feb. 1984, H.W. Churchill, G. de Nevers & H. Stockwell 4909 (MO).
Panama Chiriquí: 1100 m, 8.45N 82.13W, 8 Feb. 1984, H.W. Churchill, G. de Nevers & H. Stockwell 4811 (MO).
Panama Chiriquí: 1100 m, 8.45N 82.14W, 20 Sept. 1984, H.W. Churchill & A. Churchill 6163 (MO).
Panama Chiriquí: 08.45N 82.18W, 24 July 1994, Thomas B. Croat & Guanghua Zhu 76392 (GH, MEXU, MO, OOM, PMA).
Panama Darien: 800-1000 m, 7.59N 78.25W, 24 Mar 1986, Barry Hammel, O. Franco, C. de Gaiza & J. Trainer 14844 (MO).
Panama Panamá: 1200 m, 8.41N 82.14W, 24 May 1984, H.W. Churchill 5281 (MO).
Panama San Blas: 800-850 m, 9.18N 79.16W, 20 Nov. 1985, G. de Nevers, A. Henderson, H.Herrera, G.McPherson & L.Brako 6300 (MO).
Panama San Blas: 850 m, 9.18N 79.16W, 25 April 1985, Greg de Nevers, H.Herrera, B.Hammel & S.Charnley 5543 (MO).