This page contains photos and description of a species, form or cultivar of Costaceae.

Gingersrus Database Taxon ID 7534

Costus comosus


OLD NAME: Costus comosus - Panama form

NEW NAME: Costus comosus

NAME CHANGE NOTES: form from Panama with globular inflorescence and bicarinate bracteole

FULL SCIENTIFIC NAME:

STATUS : distinct form

CONTINENT: Neotropical

FIELD OBSERVATIONS:(If field observations are available, you can click on the link to open in a new window.)
FIELD OBSERVATIONS

PHOTOS:(If photos are available, you can click on the link to open in a new window.)

SYNONYMS:


BOTANICAL NOTES:
In 2008 I was in Panama, Santa Fe de Veraguas, and hiked the trail to the top of Cerro Mariposa (often incorrectly referred to as Cerro Tute, which is the next mountain to the south). Along the trail I saw some plants with globular shaped inflorescence, with red appendaged bracts but no fresh flowers. I did not know what it was but collected a bract, bracteole and calyx for further examination. It was not until a couple of days later that I examined it and to my surprise saw that it had a two-keeled (bicarinate) bracteole - something that was known in Costus only from two species from the Osa Peninsula of Costa Rica - Costus ricus and Costus osae. Further research revealed that this was a form that had been determined as belonging to the species Costus comosus, but it was nothing at all like other examples of that species I had seen. I found that the only collections in Panama that had been determined as that species were in the mountainous regions of west central Panama, from the Fortuna reserve to the Santa Fe area.

A thumbnail page showing photos of my first encounter in 2008 with this form of C. comosus can be found at http://www.gingersrus.com/images/R3139. Based on the morphology, I thought it looked closest to Costus ricus or possibly to Costus montanus.

In 2019 I returned to Panama with the primary goal of investigating this form further. I found it in full flower in the Fortuna area and also in the Santa Fe area at the Alto de Piedra and along the trail up the Cerro Mariposa. I examined several plants from both areas and all of them had the same globular shaped inflorescence with a bicarinate bracteole. My observations can be found on Inaturalist at the link shown above.

I have also examined available herbaria sheets for all other collections in Panama that have been determined as Costus comosus., including Antiono 2008, Croat 37213, Croat 66544, Croat 76915, Dressler 1617, Folsom 3053, Knapp & Dressler 5460, Maas 1655, Maas 2004, and Sytsma 4665 - all of which are imaged and available on the bioportal at https://bioportal.naturalis.nl/. These all show the same globular shaped inflorescence consistent with this form and quite different looking on herbaria sheets from the other forms of Costus comosus.

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 two samples of this form, one from the Fortuna Reserve and the other from Cerro Mariposa and the two samples were in a well-supported clade, far separated from three other forms of Costus comosus and closest to a sample of Costus wilsonii collected by Paul Maas (M9515) in the Fortuna area. Additional sampling is planned and if this is borne out in the final phylogeny, I think this is conclusive evidence that this form is a separate species and should be described and published as such.

HORTICULTURAL NOTES:
As far as I know, this form is not in cultivation. I have tried to grow it from collected seeds but so far have not succeeded.

ACCESSIONS:Click links (if any) to see details of individual collections. R3139- R3494- R3495- R3500- R3502- R3505-


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Photos (if available) of Taxon ID 7534
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Costus comosus, Panama bicarinate bracteole form, photo from Skinner R3500, Fortuna area, Panama - Click to see full sized image
Photo# 185 Accession# R3500
Costus comosus, Panama bicarinate bracteole form, photo from Skinner R3500, Fortuna area, Panama


Costus comosus, Panama bicarinate bracteole form, photo from Skinner R3500, Fortuna area, Panama - Click to see full sized image
Photo# 186 Accession# R3500
Costus comosus, Panama bicarinate bracteole form, photo from Skinner R3500, Fortuna area, Panama