Gingersrus Database Taxon ID 7622
CURRENT NAME: Costus sp. nov.
PROPOSED NAME: Costus alticolus
NAME CHANGE NOTES: New species published March 22, 2023 in PhytoKeys 222: 75-127, found in Oaxaca, Mexico at high elevations
FULL SCIENTIFIC NAME: Costus alticolus 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 alticolus was published March 22, 2023 in PhytoKeys 222: 75-127 by Paul and Hiltje Maas. In August 2017 I was planning a trip to Oaxaca, Mexico and Paul Maas asked me to check for a new species he was proposing to describe, to be called Costus alticolus. Assisting me was Manuel GutiÃ©rrez, a naturalist living in Oaxaca and well known to the indigenous people of the area from whom we would need permission to search for the plants. I took detailed measurements and many photos to assist Dr. Maas in completing the description of this new species.
My field observations may be seen at the link above.
This new species is named for its habitat in the mountains and cloud forests of Oaxaca, Mexico. The holotype is Solheim & Reisfeld 1367 which is at the herbarium WIS, no photo available. It produces an inflorescence on a separate basal shoot, with bright red non-appendaged bracts and yellow tubular flowers. The flowers have a stamen far exceeding the labellum exposing the thecae and thus is quite similar to several other basal flowering species, including Costus asteranthus, Costus geothyrsus and Costus stenophyllus. The plant grows to about 3 1/2 meters tall and parts are totally glabrous. The flowering shoots can be quite long, sometimes growing to nearly a meter tall. Typically a plant produces many very showy flowering shoots and I have seen as many as 25 flowering shoots from a single plant. This new species is known only from Oaxaca, Mexico where it grows on the eastern side of the mountains between Oaxaca City and San Juan Bautista Valle Nacional at elevations between 1200 and 1900 meters. It is quite common in a very localized area, especially in the area around Santa Cruz Tepetotutla. This area is cloud forest with many pine trees, and quite an unusual habitat for Costus.
As a new species, there is not much documentation about flowering period, but based on limited collection data it appears that this can flower anytime during the year. When I visited there in August, most plants were in full flower with well developed inflorescences. I have seen this growing along roadsides and in forest areas, as noted above at high elevations, in areas classified as cloud forest.
A tissue sample from my collection R3400 has been included in a molecular phylogeny of nearly all species of Costus, and has been found to be in a separate clade, closely related to Costus sepacuitensis.
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