Spathacanthus parviflorus Leonard, Proc. Biol. Soc. Washinton 50: 15-16. 1937.

Burgos-Hernandez, Mireya & Castillo-Campos, Gonzalo, 2020, Taxonomic revision of the Mesoamerican genus Spathacanthus (Justicieae, Acanthoideae, Acanthaceae), PhytoKeys 144, pp. 31-55 : 31

Spathacanthus parviflorus Leonard, Proc. Biol. Soc. Washinton 50: 15-16. 1937. Figs 8 , 9

Type.

Guatemala. Quetzaltenango: in heavy forest of volcán Zunil, 1750 m a.s.l., 7 Aug 1934. A. Skutch 961 (holotype US!; isotypes A!, BM!, L!, NY!, US!).

Description.

Small trees or shrubs, up to 8 m tall, branched, internodes glabrous or nearly glabrous. Stems subquadrate to somewhat compressed when young, nodes sparsely pubescent with rigid to flexible eglandular trichomes. Leaves petiolate, petioles 5-45 mm long, blade elliptic to obovate-elliptic, 20-155 mm × 11-100 mm, apically acute to acuminate, basally acute, marginally entire, both surfaces glabrous or with eglandular trichomes along main veins, these conspicuous on abaxial surface. Inflorescence terminal, rarely axillary, rachis glabrous to pubescent with eglandular trichomas; bracts triangular to subulate, 1.3-6 mm × 0.8-1.4 mm, abaxial surface glabrous or pubescent like rachis; bracteoles triangular to subulate, 1-4 mm × 0.6-1 mm, abaxial surface glabrous or pubescent like rachis. Flowers pedicellate, pedicels 1-13 mm long, glabrous; calyx yellowish before fruiting, turning green in ripe fruit, 20-30 mm × 6.5-11 mm, abaxially glabrous, unequally divided into 2 prominent lanceolate-ovate to ovate segments, 25 mm long on posterior side and 7-17 mm on anterior side; anterior segment bilobed, lobes triangular, 0.3-0.7 mm long; the posterior segment trilobed, triangular lobes, 0.6-0.8 mm long; corolla white, 25-30 mm long × 15-25 mm wide, externally glabrous and internally pubescent, throat 12-18 mm long × 2-6 mm in diameter near midpoint, upper lip 2-3 mm long, lobes rounded, 1.5-3 mm × 1.5-2 mm, lower lip 2.5-3.5 mm long, lobes rounded, 1.3 mm × 1.5-2.5 mm. Stamens whitish, longer pair 11-15 mm long from the base to the apex of the thecae, shorter pair 8-12 mm long; anthers dithecous, thecae 3-4.5 mm long; style glabrous 10-17 mm long; stigma lobes, 0.4-0.9 mm long. Capsule 37-60 mm long, stipe 20-35 mm long, head 17-25 mm long. Seeds subcircular to subcordate, 6-10 mm long, 6-8 mm wide, surface roughened.

Distribution, habitat and phenology.

Spathacanthus parviflorus occurs in Mexico (Veracruz, Chiapas) and Guatemala (Chimaltenango, Quetzaltenango, San Marcos, Sololá and Suchitepéquez) (Fig. 1B ), along streams and flooded areas, mainly in cloud forest, less frequently in other humid forests. It has been collected at 1000 to 2300 m a.s.l. Flowering takes place throughout the year, with ripe fruits from September to February.

Specimens examined.

Mexico. Chiapas: Mpio. Mapastepec, El Triunfo Biosphere Reserve, along trail from El Paval to camp. El Triunfo, 1940-2030 m a.s.l., 10 Nov 1996, T. Daniel et al. 8403 (ENCB, K, MEXU, MO, NY, US); Mpio. Mapastepec, El Triunfo Reserve. Trail NNW from El Triunfo camp toward Palo Gordo Camp., 1-3 km from El Triunfo camp. El Triunfo Reserve, 2000 m a.s.l., 21 Feb 1990, R.J. Hampshire et al. 522 (MEXU); Reserva El Triunfo (campamento/HQ), near campamento El Triunfo, 2000 m a.s.l., Sep 1989, M. Heath & A. Long MA84 (CHIP, MEXU); Reserva El Triunfo, polígono 1, campamento /HQ - finca Prusia, 1900 m a.s.l., 11 Dec 1989, M. Heath & A. Long 491 (CHAPA, MEXU); between Cañada Honda and El Triunfo, slopes of sierra de Soconusco, 1300-2100 m a.s.l., 06 Nov 1945, E. Xolocotzi & A. Sharp 338 (DS, MEXU); Reserva de la Biosfera El Triunfo, polígono zona núcleo I, 1800 m a.s.l., 06 Aug 2005, N. Martínez 1149 (MEXU); Reserva El Triunfo, Palo Gordo-finca Catarrinas, M. Heath et al. 738 (CHIP); Mpio. La Concordia, camino entre finca Custepec and San Antonio Miramar (pass), M. Heath & A. Long 834 (CHIP); Reserva de la Biosfera El Triunfo, N. 1850 m a.s.l., 16 Jun 1994, Ramírez-Marcial & P. Quintana-Ascencio 507 (CAS, MEXU); Mpio. Undetermined, Mt. Pistar, 03 Aug 1937, E. Matuda 1696 (F, MO, NY, UT, US). Veracruz: Mpio. Uxpanapa, Arroyo Zarco, 15 km al S de La Laguna, 200 m a.s.l., 24 Nov 2012, G. Castillo-Campos & L. Aragón A. 27651 (XAL). Guatemala. Chimaltenango: SW slope of volcán Fuego above finca Montevideo, J. Steyermark 52100 (F, US). Quezaltenango: 1400-2250 m a.s.l., 14 Jun 2005, M. Pérez 563 (MO); Pacific escarpment, 3 km S of Santa María Planta eléctrica on Hwy 9S, K. Roe et al. 715 (BM, US); volcán Zunil, 1737 m a.s.l., 07 Aug 1934, A. Skutch 961 (F, IEB); along Quebrada San Gerónimo, finca Pirineos, lower S-facing slopes of volcán Sta. María, between Sta. María de Jesús and Calahuaché, J. Steyermark 33359 (F); lower S-facing slopes of volcán Santa María, between Santa María de Jesús and Calahuaché, J. Steyermark 33507 (F). San Marcos: La Trinidad, ca. 2 km from finca Armenia above San Rafael, 1100-1250 m a.s.l., 12 Jul 1977, T.B. Croat 40846 (CAS, MEXU, MO); finca Armenia, San Rafael Pie de la Cuesta, 1524 m a.s.l., 06 Jul 1977, J.D. Dwyer 14412 (CAS, MO); finca Armenia, San Rafael Pie de la Cuesta to Carrizal, past finca África, 1300-1600 m a.s.l., 09 Aug 1980, J.D. Dwyer 15340 (MEXU, MO); volcán Tajumulco, above finca Porvenir on "Todos Santos Chiquitos", J. Steyermark 37204 (F). Sololá: sin localidad, 1000 m a.s.l., Aug 1993, M. Flores, 27 (MO); finca Mocá, Guatalón, S slope of volcán Atitlán, W. Hatch & C Wilson 342 (F). Suchitepéquez: Sta. Bárbara, finca Sta. Adelaida, K. Lind 69 (F); volcán Sta. Clara, between finca El Naranjo and upper slopes, J. Steyermark 46632 (CAS, F, NY, US).

Figures

Figure 1. Distribution of the Mesoamerican genus Spathacanthus Baillon. A Distribution of S. hahnianus and S. hoffmannii B distribution of S. magdalenae and S. parviflorus.

Figure 8. Spathacanthus parviflorus Leonard. T. F. Daniel 8403 (MEXU), Mexico: Chiapas, Reserva de la Biosfera El Triunfo.

Figure 9. Spathacanthus parviflorus Leonard. Image and legend modified from Gibson (1974) Flora of Guatemala 24, part X, page 446. A Habit, x 1 / 2 B flower with bracts and bracteoles, x 1 1 / 2 C corolla opened, with pistil removed, to show didynamous stamens, x 1 1 / 2 D opened calyx, x 1 1 / 2 E capsules with calyces, one opened to show retinacula and seeds, x 1.