Gingersrus Database Taxon ID 3602
OLD NAME: Costus lasius
NEW NAME: Costus lasius
NAME CHANGE NOTES:
FULL SCIENTIFIC NAME: Costus lasius Loes.
STATUS : accepted
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GOOGLE PHOTO ALBUM
- Costus nutans auct. non K.Schum.: Rowlee (1922)
Costus lasius is an accepted neotropical Costus species first described by Loesner in 1929. The holotype was collected by Ernst Ule in June 1902 and originally labeled as Costus villosissimus Jacq. probably based on the dense hairs. It was collected in Peru, Dept. Loreto, near Leticia at the border with Colombia and Brazil. The holotype specimen was destroyed in Berlin 1943 and Paul Maas selected as a neotype a collection in 1949 by H. A. Allard No. 22060 at "Arroyo Bravo on road to Divisoria about 40 km from Tingo Maria on the highway to Pucallpa". In November 2016 I searched for this species in this area but was unable to find it. The name "Arroyo Bravo" was unfamiliar to my guide, but the poblado "Divisoria" is in an area along the highway from Tingo Maria to Pucallpa. The elevation here is about 1500 meters which is unusually high for this species, and I wonder if perhaps there has been an error in the locality described.
Costus lasius is a short plant, normally only about 1 meter with thin stems. It is characterized by densely hairy stems, leaves and bracts. The terminal inflorescence is comprised of yellow non-appendaged bracts and yellow tubular flowers with the corolla lobes uniquely ballooned out from the labellum.
Costus lasius is one of the most widespread species geographically from Costa Rica through Panama and northwestern Colombia, then across the Andes in Amazonian Ecuador, Peru, Bolivia and Brazil. I have seen this species myself in these far-reaching places, Costa Rica on the Osa Peninsula, Panama near El Valle, Colombia ChocÃ³/Bahia Solano, deep in the Amazonian jungle of Peru off the Rio Napo and southern Peru, Madre de Dios, Manu, and the state of Acre in western Brazil. The amazing thing to me, is that despite the wide geographic range, these plants have looked nearly identical in all the places I have seen them, the only difference being one small population in El Valle, Panama that was nearly glabrous instead of the normal hairiness. Particularly unique about this species is the corolla lobes that balloon out giving the tubular flowers a unique shape and this seems to be universal despite the wide geographic range. Costus lasius has been recorded in flower all year round even in areas with a distinct dry season.
In 2014 I completed an IUCN Red List assessment for this species and it is now classified as Least Concern. My assessment rationale can be found at http://www.iucnredlist.org/details/full/56346393/0.
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. Costus lasius has been well sampled for DNA at Cornell University and it is in a well supported clade with sampling across its range. The sample R3242 collected in Panama was whole genome sequenced in the Chelsea Specht Lab at Cornell.
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