Costus gibbosus D.Skinner & Maas, 2023

Maas, Paul J. M., Maas-van de Kamer, Hiltje, Andre, Thiago, Skinner, David, Valderrama, Eugenio & Specht, Chelsea D., 2023, Eighteen new species of Neotropical Costaceae (Zingiberales), PhytoKeys 222, pp. 75-127 : 75

Costus gibbosus D.Skinner & Maas sp. nov.

Diagnosis.

Costus gibbosus sp. nov. (Fig. 12 ) can readily be recognized by the swollen margin of the lower leaf sheaths; the inflorescence is similar to that of Costus guanaiensis Rusby var. Costus guanaiensis macrostrobilus (K.Schum.) Maas, from which it differs by the horizontal orientation of the bract appendages with often incurved apex and the mostly glabrous leaves, bracts, and calyx.

Type.

Ecuador, Pichincha: along the road from Aloag to Santo Domingo , 1150 m (" 3500 ft "), 17 Nov 1974, Plowman & Davis 4455 (holotype U1212018; isotypes GH, USM) .

Description.

Herb 1.5-5 m tall. Leaves sheaths 15-35 mm diam, the margin of the lower ones swollen; ligule truncate to slightly 2-lobed, often with a ridge near the apex, 7-14 mm long; petiole 10-15 mm long; sheaths, ligule and petiole glabrous to densely puberulous; lamina narrowly elliptic, 30-50 × 10-20 cm, slightly shiny above, pale green to slightly glaucous below, adaxially glabrous, rarely puberulous, abaxially glabrous, sometimes densely puberulous to villose, base acute to cordate, apex acuminate (acumen 15-20 mm long) to acute. Inflorescence ovoid to cylindric, 11-18 × 5-9 cm, terminating a leafy shoot; bracts, bracteole, and calyx glabrous, rarely rather densely puberulous, ovary and capsule glabrous to densely puberulo-sericeous. Flowers abaxially oriented; bracts red, coriaceous, broadly ovate, 40-50 × 30-40 mm; appendages green, foliaceous, erect, broadly triangular to triangular, 15-60 × 10-30 mm, often incurved at the apex; bracteole boat-shaped, 22-32 mm long; calyx red to pink, rarely white, (7-)12-20 mm long, lobes deltate to shallowly triangular, 2-5 mm long; corolla pale yellow, white, or pink, 60-70 mm long, glabrous, lobes ellliptic, 45-60 mm long; labellum pale yellow, orange, pinkish, or white, distal edge horizontally spreading, broadly obovate, 60-85 × 50-70 mm, lateral lobes erect, more or less striped with pink or red, middle lobe reflexed, with yellow honey mark, margin irregularly dentate to lobulate; stamen pink, red, yellow, or white, 40-50 × 12-15 mm, not exceeding the labellum, apex irregularly dentate, anther 9-13 mm long. Capsule ellipsoid to narrowly ellipsoid, 12-20 mm long.

Distribution.

Ecuador (El Oro, Esmeraldas, Guayas, Loja, Manabi, Pichincha) (Fig. 22A ).

Habitat and ecology.

In forested roadsides, dry forests, or gallery forests at elevations of 0-1500 m. Flowering year-round.

Etymology.

Costus gibbosus sp. nov. is named for the swollen upper margin of the lower leaf sheaths.

Paratypes.

Ecuador. Bolivar: Caluma, Pasagua Road, 836 m, Skinner R3344, Caluma-El Mirador, 185 m, Skinner R3346. El Oro: between Piñas and Piedras, 1000 m, Asplund 18160 (S); Road from Santa Rosa to Piñas, 3 km E of Playón, 8 Feb 1987, 350 m, Bohlin 1226 (GB, QCA); Camino a Limón-Playa, cerca a Río Dumari, 600 m, 12 Oct 1993, Cornejo & Bonifaz 425 (AAU, QCNE); Road Zaruma-Santa Rosa, between Piñas and El Placer, 800 m, 6 May 1974, Harling & Andersson 14354 (GB, U). Esmeraldas: Hacienda Timbre, 28 May 1955, Asplund 16494 (S); along road to Río Tulubí from main San Lorenzo-Lita Highway, 12 July 2000, 59 m, Croat 83948A (MO, QCNE); between Esmeraldas and Tabiazo, 0 m, 14 Sep 1977, Maas et al. 2915 (QCA, U). Guayas: Guayaquil, Cerro Azul, Asplund 15412 (S); Cerro Azul, W of Guayaquil, 25 Mar 1955, Asplund 15895 (NY, S); Cordillera Chongón-Colonche, Río California, 150 m, 27 Sep 1997, Cornejo & Bonifaz 5792 (GUAY, U); Cerro Azul Cordillera Chongon-Colonche, 12 km W of Guayaquil, Quebrada Canoa, 17 Jan 1991, 50-300 m, Gentry & Josse 72332 (F, MO, QCNE); Teresita, 3 km W of Bucay, 270 m, 5 Jul 1923, Hitchcock 20543 (GH, NY, US); Bosque Protector Cerro Blanco, Carretera Guayaquil-Salinas, km 17, 200-440 m, 31 Oct 1995, T. Nuñez 306 (MO, QCNE); Cantón Guayaquil, Bosque Protector Cerro Blanco, carretera a Salinas, km 15, 100 m, 19 Aug 1991, Rubio et al. 2007 (MO, QCNE, U). Loja: Macará-Cariamanga Road, ca. 3 km NE of Sabiango, 900-1000 m, 17 Apr 1980, Harling & Andersson 18358 (S, U). Los Ríos: Río Palenque Biological Station, 220 m, 17 Sep 1973, Dodson & Tan 5347 (F, QCA, US); Río Palenque Science Center, km 56 of Quevedo-Santo Domingo Road, 14 May 1982, Dodson 13039 (MO, SEL); Río Palenque Field Station, halfway between Quevedo and Santo Domingo de los Colorados, 200 m, 24 Feb 1974, Gentry 10165 (MO, RPSC, SEL). Manabi: 40 km along road from Santo Domingo de los Colorados to Chone, 19 May 1955, Asplund 16421 (S); El Aromo, 13 km SW to San Mateo, then E 13 km to town, 100 m, 4 Dec 1986, Hammel & Trainer 15871 (MO); road Chone-El Carmén, at Flavio Alfaro, 350 m, 28 Oct 1980, Holm-Nielsen et al. 27916 (AAU). Pichincha: shore of Río Pilatón, at the bridge of the road from Chiriboga to Santo Domingo de los Colorados, 1000 m, 2 Jul 1955, Asplund 16763 (S); Santo Domingo de los Colorados, 530 m, 19 Jun 1975, Gilli 119 (W); new Alluriquín-Quito Road, km 6, 850 m, 10 Oct 1980, Maas & Cobb 4795 (NY, QCA, U); Santo Domingo de los Colorados, 200 ft, 28 Oct 1960, Pennington 56 SD (K, NY); along the road from Aloag to Santo Domingo, Tandape, 1150 m ("5000 ft"), 17 Nov 1974, Plowman & Davis 4454 (GH, U); Toachi, on road Aloag-Santo Domingo, 750 m, 3 Jan 1967, Sparre 13862 (S, U); Carretera Quito-Puerto Quito, km 113, near Reserva de ENDESA “Corporación Forestal Juan Manuel Durini", 800 m, 4 Mar 1984, Ulloa U. 111 (QCA, U).

Notes.

Costus gibbosus sp. nov. is easily recognized in the field by the swollen margins of the lower leaf sheaths.

Figures

Figure 12. Costus gibbosus D. Skinner & Maas A plant in cultivation at Rio Palenque Science Center, Ecuador with Dave Skinner B inflorescence showing the recurved apices of the bract appendages C lower leaf sheaths showing swollen margins D close-up of bract (left) and flower (right) E plant in habitat near Caluma, El Oro, Ecuador B, C at Waimea Arboretum, Hawaii 74 S 2037, grown from seeds collected by Tim Plowman D, E Photos of plant in the wild prior to collecting seeds for D. Skinner R 3346, currently in cultivation. Photos A-E by Dave Skinner.

Figure 22. Distribution maps for new species of Costaceae. Costus gibbosus - Costus whiskeycola m A Costus gibbosus D. Skinner & Maas B Costus mollissimus Maas & H. Maas C Costus obscurus D. Skinner & Maas D Costus oreophilus Maas & D. Skinner E Costus pitalito C. D. Specht & H. Maas F Costus prancei Maas & H. Maas G Costus pseudospiralis Maas & H. Maas H Costus rubineus D. Skinner & Maas I Costus whiskeycola Maas & H. Maas.