Plant Datasheet for Costus arabicus

The TYPE is a drawing by Ehret of a plant cultivated in the Hortus Cliffortianus, deposited in the library of Sir Joseph Banks.

SYNONYMY: The following collections have been placed into synonymy with Costus arabicus.

Costus validus Loes. - Holotype collected in 1911 by E. H. G. Ule in Peru, Rio Acre.

Costus spiralis var. hirsutus Petersen - Isotype collected in 1849 by A. F. Regnell in Brazil, Minas Gerais.

Costus pilgeri K.Schum. - Isolectotype collected by Emile Hassler in Paraguay, Canindeyú, Iter ad Yerbales montium Sierra de Maracayú. In regione fluminis Tapiraguay.

Costus ramosus Woodson - Isotype collected in 1938 by Albert Smith in Guyana, Basin of Shodikar Creek (Essequibo tributary), ca. 1°18'N

Costus gracilis Loes. - Holotype collected by E. H. G. Ule in Peru

I have seen this species in several places over a wide range - Amazon basin near Iquitos in Peru, Guyana at Iwokrama (with a two-keeled, bicarinate bracteole), central Brazil at Cristolino, and southeast Brazil, Espirito Santo.

TAXONOMY NOTES BY BRIAN MIDDLEDITCH - Costus arabicus L.: Costus arabicus has an intriguing history. The Dutch botanist van Rheede tot Drakestijn in 1692 described a plant that he called Tsjana-Kua (this was almost 100 years before the universal adoption of the genus-species system of nomenclature). He commented that it resembled Kostos arabikos, a plant described by the Greek physician Dioscorides (c. 40 -90 AD) in his De Materia Medica. But "Kostos arabikos" was unrelated to Tsjana-Kua and the modern genus Costus. It was a composite, possibly Saussurea lappa. Linnaeus (in 1737 - again, before the publication of his seminal Species Plantarum) came across your plant while cataloging the Hortus (garden) of Cliffort. He believed that it was identical to Tsjana-Kua, and he named it Costus arabicus as a tribute to Dioscorides. But the story does not end there. Tsjana-Kua is now known to be today's Costus speciosus (which originated in India and Southeast Asia). As luck would have it, though, the plant that Linnaeus described in 1737 was an entirely different species (from South America), that still - quite legitimately - bears the name Costus arabicus.

Checklist of the Plants of the Guianas - gopher://nmnhgoph.si.edu:70/0R217674-219444-/.docs/guianas_data//checkl2 - Costus arabicus L. [GU SU FG] NOTE: I found Costus arabicus in Guayana growing along the Rio Essequibo and was surprised to find that the bracteole was the bicarinate (two-keeled) shape instead of the normal Costus single-keeled boat shape as in other specimens of this species.

ANGUS BOTANICAL PRINTS - TITLE: Costus discolor. 1 print : lithograph, hand col. ; 54 x 42 cm. Published in William Roscoe, Monandrian Plants of the Order Scitamineae Chiefly Drawn from Living Specimens in the Botanical Gardens atLiverpool, pl. 81. Botanical illustration of a member of the ginger (Zingiberaceae) family. NOTE: C. discolor is obsolete synonym for C. arabicus. Roscoe called it C. discolor because the undersides of the leaves of his specimen were "scarlet" compared to the green upper sides. He also said the shape of the flower resembles an Egyptian mummy.

ACCESSION NOTES:
R2260 from Smithsonian USBG1992-033 has a nearly pure white labellum with very pale yellow nectar entrance.

R2979, R2980 & R2990 all from John Banta, origin unknown; R3021 called "Stokes White" origin unknown;

R3122 from Quistococha, Peru near Iquitos has been vouchered at the UC Berkeley, Jepsen Herbarium, UC2045806. It has dark pink markings and a yellow throat to the labellum. Does not produce the branching habit this species is known for. It does have the distinctive cordate leaf base and otherwise is consistent with the species characters.

Peru; R3124 from Rio Mazon, Peru has been vouchered at the UC Berkeley, Jepsen Herbarium, UC2045805. It has the pure white labellum with yellow throat, but is different from others by having bracts red at base and partially exposed red below the green apex.

R3214 from Iwokrama, Guyana was aberrent in having a bicamerate (two-keeled) bracteole, something found in only two other Costus species (C. osae and C. ricus).

R3253 from Cristalino, Brazil did not survive.

OBSERVATION NOTES:

Ariosto Island, Rio Teles, State of Mato Grosso, Brazil, Latitude -9.63, Longitude -55.94, at 230 meters elevation.

Turtle Mtn Base Camp, Iwokrama, Guyana, Latitude 4.749, Longitude -58.812, at 65 meters elevation.

Quistococha, Peru, Latitude -3.828, Longitude -73.324, at 100 meters elevation.

along Rio Mazán, Maynas Province, Peru, Latitude -3.51439, Longitude -73.14, at 90 meters elevation.

Quebrada Cayapoza, off Rio Napo, Maynas Province, Peru, Latitude -3.429, Longitude -73.16, at 100 meters elevation.

GINGERSRUS CATALOG LISTING:
Costus arabicus is a vigorous growing Costus, and is in fact the type species for the genus. It is characterized by pure white flowers with a splash of yellow in the labellum, green bracts, stems that branch as in Cheilocostus, and a cordate leaf base. As the inflorescense matures, the bracts will sometimes open up exposing their bright red interiors and putting on a "second show" so to speak.

I have seen this plant in nature in Amazonian Peru, in Guyana and in Brazil. In nature it is usually found along river banks and in relatively wet places, so that should give us a clue on how to grow it.

The foliage is tropical and attractive, medium green, spiraling around the sheaths. The late Bob Riffle, in The Tropical Look gave this a conservative cold hardiness rating of zone 9B, but I have found this Costus to be susceptible to rotting of the rhizomes if left outside in winter wet conditions while dormant. This Costus will grow well in a range from part sun to filtered shade. During active growth it needs rich, moist, organic soil.