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PLANT FAMILY: Costaceae
BOTANICAL NAME: Costus acreanus
FORMAL SCIENTIFIC NAME: Costus acreanus (Loes.) Maas
Costus acreanus is a valid neotropical species described by Paul Maas in his 1972 monograph. It was originally described by Loesener in 1929 as Costus cylindricus var. acreanus. Maas describes it as being in the group with non-appendaged bracts and open flowers with distribution being in southwestern Brazil and adjacent parts of Peru in marshes, varzea forests and low hills to 700 meters. In 1977 he added amazonian Colombia to the area of distribution. The type is from the Rio Acre in Madre de Dios, Peru near the Brazil border. It was collected by Ernst Ule in 1911 and the herbarium specimen is at Kew Gardens in UK. Very few details are visible on the specimen.
There seems to be a lot of confusion about this species, with photos on the web showing a basal flowering plant, but specimens I have found that were determined by Maas as C. acreanus all are terminal flowering.
My research paper I prepared prior to going to the Manu area of Peru can be seen at http://www.gingersrus.com/botanical/CostusSpeciesUpperManu.pdf. My notes pertaining to C. acreanus begin on page 3 of this document.
PDF file with photos of Costaceae of Colombia include a photo of C. acreanus which seems to match the description in Flora Neo Tropica. See photo #2 on this document.
In 2014 I was in Brazil and visited the herbarium at the Jardim Botanico in Rio de Janeiro. There I found three sheets all det'd by Paul Maas as C. acreanus - one from state of Acre and two from Amazonas. They all have clearly NON-appendaged bracts and are terminal flowering plants. A collection by Daly et al, #9990, from the Rio Purus in Acre, Brazil is described as having the undersides of leaves a deep glossy red, bracts green tinged with red, flower pink with two broad yellow stripes.
I believe that the Costus known as 'El Whiskey' that I have seen in Manu, Peru and in the Tingo Maria area of Peru is likely to be the same species as the plant originally collected by Ule along the Rio Acre near the Peru border with Brazil that is the type for Costus acreanus. A field trip to that region might provide some answers to this species. Go to PID7260 for more details about Costus 'El Whiskey'.