Costus mollissimus Maas & H.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 mollissimus Maas & H.Maas sp. nov.

Diagnosis.

Costus mollissimus sp. nov. (Fig. 13 ) shares with C. dirzoi Garcia-Mend. & G.Ibarra a distinct velutinous indument on most parts of the plant, but differs by having appendaged bracts and a very short ligule. Moreover, C. dirzoi has bracts with a distinct callus, absent in C. mollissimus .

Type.

Mexico, Chiapas: Mun. Chilon, 22 km from Temo in the direction of Palenque, 2 km from Patathel , near El Chich , 850 m, 4 Nov 1998, Ishiki Ishihara, Maas & Maas-van de Kamer 2400 (holotype L, 2 sheets: L4368349 & L436835; isotype ECOSUR) .

Description.

Herb 0.5-2.5 m tall. Leaves sheaths 12-15 mm diam; ligule truncate, 1-4 mm long; petiole 10-15 mm long; sheaths, ligule and petiole densely velutinous; lamina narrowly elliptic, sometimes elliptic, 18-36 × 6-13 cm, slightly 5-8-plicate, adaxially shiny, glabrous, abaxially densely velutinous, base acute, obtuse, to cordate, apex acuminate (acumen 5-15 mm long). Inflorescence cylindric to subglobose, 5-13.5 × 4-5 cm, terminating a leafy shoot; bracts, appendages of bracts, bracteole, calyx, ovary, and capsule densely velutinous. Flowers abaxially oriented; bracts green, red, or pink, coriaceous, broadly elliptic, 2-2.5 × 2-3 cm; appendages green, foliaceous, patent to slightly reflexed, triangular to broadly triangular, 0.5-3.5 × 1.2-2.5 cm, apex acute to obtuse; bracteole boat-shaped, 16-20 mm long; calyx red to pink, 9-10 mm long, lobes broadly to shallowly triangular, 2-5 mm long, with a hairy tuft at the apex; corolla cream, yellow, or pale orange, 50-60 mm long, densely velutinous, lobes narrowly elliptic, 30-40 mm long; labellum yellow, distal edge horizontally spreading, broadly obovate, 30-40 × 40-50 mm, lateral lobes dark red with yellow venation, middle lobe reflexed with yellow honey mark, margin dentate; stamen yellow, 30-35 × 10-12 mm, not exceeding the labellum, apex red, slightly 3-dentate, anther ca. 8 mm long. Capsule broadly obovoid to obovoid, 12-17 mm long.

Distribution.

Mexico (Chiapas, Oaxaca, Tabasco, Veracruz) (Fig. 22B ).

Habitat and ecology.

In forests (a.o. "selva baja/alta perennifolia") with Brosimum sp., Bursera sp., Calophyllum sp., Cymbopetalum sp., Dialium sp., Ficus sp., Tapirira sp., and Sloanea tuerckheimii Donn.Sm., at elevations of 200-1000(-1500) m. Flowering year-round.

Vernacular name.

Mexico: Apagafuego.

Etymology.

This species is named after its very soft indument on the abaxial surface of the lamina, the word “mollis” meaning soft in Latin.

Paratypes.

Mexico. Chiapas: Mun. Solosuchiapa, 3-5 km above Solosuchiapa, along road to Tapilula, 450 m, 26 Jul 1972, Breedlove 26463 (MO); Mun. Ixcomitan, 2 km E of Ixcomitan, road from Villahermosa to Tuxtla Gutierrez, 550 m, 11 Feb 1983, Martínez Salas et al. 3160 (MEXU); Mun. Pichucalco, 10-12 km S of Pichucalco, 8 Mar 1983, Ramamoorthy et al. 1790 (MEXU); NW end of Valley of Chiapas on road to Mal Paso, 41 km (by road) NW of Ocozocoautla, 350 m, 4-5 Aug 1965, Roe et al. 928 (WIS). Oaxaca: Mun. Santa María Chimalapa, Arroyo Milagrito, ca. 6 km SE of Santa Maria, 1 km from Vereda, which passes Arroyo Sanate, 230 m, 30 Aug 1984, Hernández G. 387 (MEXU, MO); Mun. Santa María Chimalapa, ca. 15 km ESE of Santa María, Vereda near Arroyo Plata, loma S of Río Milagro, 400 m, 3 Sep 1985, Hernández G. 1435 (MEXU, MO). Tabasco: near San Manuel, S of village along Río Mezcalapa, 11 Sep 1944, Gilli & Hernandez Xolocotzi 97 (MEXU). Veracruz: Las Cruces, Las Choapas, 250 m, 14 Jul 1970, Nevling & Gomez-Pompa 1526 (F).

Notes.

Costus mollissimus sp. nov. superficially resembles C. dirzoi García-Mend. & G.Ibarra, as both share the velutinous indument all over the plant, but differs in having bracts with foliaceous, green appendages and a shorter ligule (1-4 mm vs. 3-12 mm long). Costus dirzoi has bracts with a distinct callus that is absent in C. mollissimus .

In Maas’ treatment of Costaceae (" Costoideae ") for Flora Neotropica ( Maas 1972: 57), this species was erroneously included in C. guanaiensis Rusby as var. Costus guanaiensis tarmicus (Loes.) Maas.

Figures

Figure 13. Costus mollissimus Maas & H. Maas A inflorescence B ligules and sheath, showing short ligule and indument C, D cultivated plant growing in Florida, propagated from living accession 1998 GR 01567 at Utrecht Botanical Garden. Photos A, B by Paul Maas C, D 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.