Monographs Details: Costus warmingii O.G.Peterson
Authority: Maas, Paulus J. M. 1972. Costoideae (Zingiberaceae). Fl. Neotrop. Monogr. 8: 1-140. (Published by NYBG Press)
Family:Costaceae
Synonyms:Costus pumilus Petersen, Costus acaulis S.Moore, Costus paucifolius Gagnep., Costus rosulifer Gagnep., Costus latifolius Gagnep., Costus pumilus Petersen, Costus pilosissimus (Gagnep.) Schum., Costus gagnepainii K.Schum., Costus steinbachii Loes., Costus kaempferoides Loes.
Description:Description - Acaulescent or very low plants with stems to 25 cm tall and 2-8 mm wide. Roots fleshy, ending in fusiform to ellipsoid tubers, 2.5-5 cm long, 0.8-2 cm wide. Sheaths membranaceous, obtuse at the apex, 2.5-6 cm long, 0.5-2 cm wide, densely strigose, sparsely to rather densely puberulous, or glabrous. Ligule hardly 1 mm long. Petiole absent. Leaves 4-6, rosulate, obovate to elliptic or narrowly obovate to narrowly elliptic, cuneate at the base, mucronate or shortly acuminate at the apex, 5-30 cm long, 3-13 cm wide, upper side densely strigose or glabrous, lower side densely strigose, rather densely to sparsely puberulous, or rarely glabrous, margins densely ciliate to glabrous. Inflorescence 1- to 4-flowered, bracts herbaceous, green, to 40 mm long, 5-15 mm wide, glabrous to densely puberulous; appendages folia-ceous, green, narrowly triangular to deltate, mucronate at the apex, 5-35 mm long, 0.5-22 mm wide, densely puberulous to glabrous on both sides. Bracteole membranaceous, tubular, 25-32 mm long, glabrous to densely puberulous, bicarinate at the adaxial side, two-lobed at the apex, lobes narrowly triangular to deltate, 2-15 mm long. Pedicel ca 5 mm long, glabrous. Calyx membranaceous to herbaceous, 21-41 mm long, sparsely to densely puberulous or glabrous, lobes narrowly triangular to deltate, mucronate, 4-15 mm long. Corolla yellow, 55-70 mm long, glabrous to densely puberulous, tube 25-30 mm long, lobes narrowly elliptic, mucronate, 30-40 mm long, 6-12 mm wide. Labellum yellow or slightly blotched with orange at the middle, broadly obovate when spread out, 60-70 mm long, 70-95 mm wide, limb in living plants suborbicular in outline, margins crenulate and fimbriate (glabrescent with age). Stamen yellow, obovate to narrowly obovate or rarely narrowly elliptic, 35-47 mm long, 6-20 mm wide, apex obtuse, irregularly lobed or rarely acuminate, anther attached at the base, 7-8 mm long, caudate at the apex. Basal part of labellum and stamen joined into a 35-40 mm long tube. Pollen grains 158-210 µ. Exine ca 2 µ thick. Number of pores 10-16. Porus diam 18-25 /z (Macedo 1993 and Silva 57750, both from Brazil). Stigma cup-shaped. Ovary 5-13 mm long, rather densely to densely sericeous or glabrous. Capsule unknown. Calyx-lobes, corolla, labellum, and stamen usually red-brown punctate.

Discussion:Costus warmingii is a highly variable species and the variability is demonstrated by the ten species which have been described in this complex but are here united. I have studied them all and found that they could not be separated from each other on floral characters, these being quite constant. The "species" differ mainly in vegetative characters like height, leaf-shape and especially hairiness and following Schumann (1904) I have tried to use them as criteria for the distinction of the several forms within this C. warmingii-complex.

The leaf-shape is somewhat correlated with the height of the plants, leaves of acaulescent plants always being obovate-elliptic and mucronate at the apex and leaves of caulescent plants obovate-elliptic to narrowly obovate-elliptic and mucronate to acuminate at the apex. I have also tried to evaluate these vegetative characters on a quantitative base in Fig 15, viz: a. height of the plants, on the horizontal axis; b. degree of hairiness, on the vertical axis, using the following scale: 1. leaves totally glabrous; 2. leaves puberulous at the lower side; 3. leaves strigose at the lower side; 4. leaves strigose on both sides; c. the leaf-shape, circular dots representing obovate-elliptic leaves and elliptic dots representing narrowly obovate-elliptic leaves.

The figure shows the tendency of acaulescent plants to be strigose; caulescent plants quite often are puberulous but less frequently strigose or, rarely, glabrous. The different forms are mixed together within southern Brazil and Bolivia and no geographic isolation of any of the forms could be observed. Probably the differences in height and hairiness are caused by environmental factors, especially by exposure to the sun, the caulescent and usually puberulous plants growing in shaded habitats and acaulescent, usually strigose plants growing in sunny places. Concluding, I may say that too many species based on characters like the ones just discussed have been distinguished in this complex; these characters, in other words, are so variable and often overlap within the same geographic region that it is impossible to assign specimens unequivocally to one of these "species" which are therefore here united under the oldest name C. warmingii. Field-notes are badly needed and it may be hoped that future collectors in southern Brazil and Bolivia will note them and will collect seeds, rhizomes, and pickled flowers.
Distribution:Brazil South America| Acre Brazil South America| Bahia Brazil South America| Goiás Brazil South America| Mato Grosso Brazil South America| Minas Gerais Brazil South America| São Paulo Brazil South America| Bolivia South America|