Costus whiskeycola 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 whiskeycola Maas & H.Maas sp. nov.

Diagnosis.

Costus whiskeycola sp. nov. (Fig. 20 ) looks quite similar to Costus erythrophyllus Loes., sharing many features of inflorescence and flowers, but it is markedly different in their leaves which lack the distinct plication and which have a dark, olive green adaxial surface.

Type.

Colombia, Putumayo: Km 42 of Mocoa-Puerto Asis Road, Quebrada El Whiskey , Finca Santa Marta , Hilltop forest , c. 400 m (" 1260 ft "), 5 Nov 1974, Plowman & Davis 4396 (holotype COL; isotype PSO) .

Description.

Herb 0.5-0.7 m tall. Leaves sheaths 10-18 mm diam; ligule 10-20 mm long, obliquely truncate; petiole 5-15 mm long; sheaths, ligule and petiole glabrous, purple-red to green; lamina ovate-elliptic to narrowly ovate-elliptic, 22-29 × 10-13 cm, dark, olive green adaxially, red-purple to dark purple abaxially, with 5-6 dark green bands corresponding with slightly raised veins above, adaxial and abaxial surfaces both glabrous, base acute, apex acute to shortly acuminate (acumen 3-5 mm long). Inflorescence ovoid, ca. 7 × 4.5 cm, terminating a leafy shoot; bracts and appendages of bracts, bracteole, calyx, and ovary glabrous. Flowers abaxially oriented; bracts red, coriaceous, broadly ovate, 3-4 × 2-3.5 cm; appendages green, foliaceous, ascending, triangular-ovate, 2.5-5 × 2-3.5 cm, apex acute; bracteole boat-shaped, 24-30 mm long; calyx red, 12-20 mm long, lobes very shallowly triangular, 2-5 mm long; corolla white, 60-75 mm long, glabrous, lobes narrowly elliptic, 45-60 mm long; labellum white, distal edge horizontally spreading, broadly obovate, 60-70 × 50 mm, lateral lobes striped with red, middle lobe reflexed with yellow honey mark, irregularly lobulate, margin crenulate; stamen white, tinged with red, 35-40 × 13-14 mm, not exceeding the labellum, apex 3-dentate, anther 8-10 mm long. Capsule not seen.

Distribution.

Colombia (Putumayo). Ecuador (Napo), Peru (Loreto) (Fig. 22I ).

Habitat and ecology.

In tropical wet forests at an elevation of 250-400 m. Flowering period is uncertain.

Etymology.

This species has been named after its type locality El Whiskey (Putumayo, Colombia), with “cola” the Latin for "living in".

Paratypes.

Colombia. Putumayo: El Chapo, 250 m, Skinner R 3463. Cultivated Material Greenhouse of “Sandwijck”, near Utrecht, the Netherlands, 3 Aug 1978, Maas 74-618 (AAU, COL, K, NY, QCA, P, U161001, U161002, US), from the type collection Plowman & Davis 4396; cultivated in USBRG as 1994-680, Skinner R 2257 (UC); cultivated in Jesse Durko Nursery, Skinner R 2847; cultivated by Bob Campos, Skinner R 2948; Smith College Botanical Garden, Skinner R 3026 (UC).

Notes.

This new species has long been widely cultivated worldwide, originally grown from seeds collected by Tim Plowman when preparing Plowman & Davis 4396 at the type locality. Until a late stage in our revision, we united this species with C. erythrophyllus Loes. Although the flowers and inflorescence look very much like those of that species, the leaves are quite different in their colour and the almost absence of distinct plication. They also have a thicker mesophil layer and are waxy in living plants. This species can also be distinguished from C. erythrophyllus by the length and shape of the ligules, which are truncate to obliquely truncate instead of being deeply lobed.

In April 2022, Dave Skinner visited the Santa Cruz private reserve of Project Amazonas near Iquitos, Loreto, Peru and found large populations of plants in primary forest that are identical vegetatively and have flowers that match those of Costus whiskeycola . However, the bracts lack leafy appendages. It is yet to be determined whether or not these plants are of this same species.

Figures

Figure 20. Costus whiskeycola Maas & H. Maas A cultivated plant grown from seeds from the Plowman & Davis 4396 accession now growing at the Utrecht Botanical Gardens, The Netherlands B cultivated plant obtained from the established nursery trade, accession D. Skinner R 2847 C flowers showing spreading labellum with lateral markings and a prominent honey mark D bracts with green and red erect appendages E comparison of leaf plication between (i) C. whiskeycola and (ii) C. erythrophyllus F comparison of ligule and leaf bases of (i) C. whiskeycola and (ii) C. erythrophyllus G comparison of leaf sections showing thicker mesophil layer in (i) C. whiskeycola v. (ii) C. erythrophyllus. Leaf images in C-D taken from plants that were pressed and accessioned as D. Skinner R 3026 (C. Costus whiskeycola sp. nov.) and D. Skinner R 2948 (C. erythrophyllus). Photo A by Lubbert Westra, photos B-F 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.