Gingersrus Database Taxon ID 7757
OLD NAME: Costus sp. nov.
NEW NAME: Costus pseudospiralis
NAME CHANGE NOTES: New species published March 22, 2023 in PhytoKeys 222: 75-127, abaxially flowering aff. C. spiralis.
FULL SCIENTIFIC NAME: Costus pseudospiralis Maas & H.Maas
STATUS : sp. nov.
FIELD OBSERVATIONS:(If field observations are available, you can click on the link to open in a new window.)
PHOTOS:(If photos are available, you can click on the link to open in a new window.)
GOOGLE PHOTO ALBUM
Costus pseudospiralis was published March 22, 2023 in PhytoKeys 222: 75-127 by Paul and Hiltje Maas. The new species looks superficially similar to Costus spiralis but the primary difference is the orientation of the flowers, abaxially oriented (out from the side) instead of adaxially oriented (upright or inward). Dr. Maas distinguishes it from another of his new species, Costus douglasdalyi, by the fact that it flowers terminally on a leafy stem whereas C. douglasdalyi usually flowers at the base on a leafless shoot. He also says the base of the wider leaves is usually cordate instead of acute to rounded. I have had difficulty distinguishing between these two species and may have incorrectly identified some of the field photos between the two.
Dr. Maas chose as his type collection a specimen from Beni in Bolivia he collected in 1999, his number 8751. He lists several other collections from Bolivia and from Rondonia in Peru as examples of his new species.
I saw many examples of this new species in the southern part of Acre, Brazil during my 2020 trip there. Dr. Maas reviewed the photos and identified the observations. In the wild, this species seems to grow much taller than the usual plant of Costus spiralis. Some plants have very small appendages at the tips of the bracts and most of them I saw have a very conspicuous nectar callus.
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 from Dr. Maas' type collection in Bolivia was included and found to be in a lineage close to C. douglasdalyi and C. guanaiensis (it's newly interpreted form), but I think additional sampling is needed to clearly determine the placement of this species.
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