Gingersrus Database Taxon ID 4607
OLD NAME: Costus nitidus
NEW NAME: Costus nitidus
NAME CHANGE NOTES:
FULL SCIENTIFIC NAME: Costus nitidus Maas
STATUS : accepted
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Costus nitidus is an accepted species of neotropical Costus described by Paul Maas in 1976 from his collection in Costa Rica, Cartago, forested hills of RÃo ReventazÃ³n, near grounds of LICA (now CATIE), near Turialba. It is very similar to Costus plicatus, and is distinguished from that species only by its narrower and less strongly plicate leaves. Both species have identical inflorescences with red non-appendaged bracts and tubular yellow flowers. Both have long, deeply lobed ligules. A difference noted by Maas that the leaves are shiny ("shining on both sides") in Costus nitidus, but I have observed that to be true of both species. Go toPID 4606 to see the datasheet and photos of Costus plicatus.
The distribution according to Dr. Maas of both Costus nitidus and Costus plicatus is in Costa Rica and Panama. In 2006 I found a Costus believed to be Costus nitidus with mature inflo (no flowers) along trail close to station at Hitoy-Cerere Biological Reserve in Costa Rica. Inflo. 15 cm tall by 5? cm wide, light green bracts, leaves 45 cm long by 5.5 cm wide, glabrous, greyish color undersides, ligule long lobed 3.5 cm, petiole 1 cm, all glabrous. Parts photographed, bracts whitish underneath, exposed part greenish, bracteoles and calyx white, all glabrous. Bracts 4 cm long by 3 cm wide, not appendaged. Bracteole 2.3 cm long by .2 cm wide, calyx .6 by .6 cm, shallow lobed. I found another specimen believed to be Costus nitidus along the trail up Cerro Mirador, which runs between Shiroles and the Valle de Estrella, in the same region as Hitoy-Cerere. This plant was tall and the vegetative parts were similar to the one seen at Hitoy-Cerere, but the bracts were bright red with very distinct and long yellow-green nectar calluses. The inflo. was over 20 cm in length. There were no flowers. The ligules were long and lobed like the other specimen. I was unable to photograph the bracteoles and calyx. Both specimens had large shiny leaves just somewhat plicate. When I showed my photos to Paul Maas, he agreed that my accession R3088 is Costus nitidus.
Since that time I have seen other plants in Panama that I was unable to determine whether they are Costus nitidus or Costus plicatus as there seem to be intermediates in the amount of plication of the leaves and that is really the only distinction between these two species.
In 2014 I completed an IUCN Red List assessment for this species and it is now classified as Endangered. My assessment rationale can be found at http://www.iucnredlist.org/details/full/56347808/0. The population data used for this assessment was based upon the determinations of identity (usually by Paul Maas) as found in GBIF data listed as this species.
A partial phylogeny was completed by Eugenio Valderrama and his associates in the Chelsea Specht Lab at Cornell University and was published in the journal Frontiers in Plant Science in September 2022. DNA was extracted from samples of two collections that were determined by Paul Maas to be Costus nitidus and they were found to be in a separate clade from Costus plicatus, but in the same lineage.
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