Plant Datasheet for Costus glaucus

Holotype: collected in 1974 by Paul Maas at Cartago, Turrialba, Rio Reventazón at 600 m.

I have seen this species several places in Costa Rica, with a wide range but not common, usually below 500 m, Golfo Dulce area, Cerro Nara, La Cangreja
At La Gamba Research Station - cultivated in garden, over 20 feet tall, inflo very large, over 12 inches. flower parts photographed July 2, 2005.
Several specimens observed between Drake and Rincon on Osa Peninsula.
Along Quebrada Grande in La Cangreja
In Cerro Nara area at higher altitudes (ca 900 m), local specimen planted in front of Cerro Nara Lodge

In 2014 I completed an IUCN Red List assessment for this species and it is now classified as Near Threatened. My assessment rationale can be found at http://www.iucnredlist.org/details/full/56345900/0.

I can usually recognize it by the white powdery substance on the newly emerging stems and sometimes also on mature stems and bracts. It is a very large plant in stature and the ligules are long and deeply lobed. The inflorescence is usually round at the apex except in very old plants where it is more elongated. I have seen two plants that look to be very close to C. glaucus and have them described and photos on separate pages atPID 7566 (now called Costus 'Red Baron') andPID 7525 (Costus from Tulipe) .

Specimen at Waimea 86P447 (had as Costus sp.) - received 1986 from Rob Montgomery, Costa Rica. Collected 14 km NE of Palmar.

In July 2016 I went to the type locality at the organization CATIE near Turrialba in Cartago Province, Costa Rica. Costus glaucus was found there, both in habitat and in the botanical garden there.

ACCESSION NOTES:
R2951 was received from Tom Wood, origin unknown. This collection has been vouchered at the UC Berkeley, Jepsen Herbarium, UC2045816.R3363 and R3364 - seeds and stem cutting collected at CATIE type locality, germinated and growing well as of January 2017.

OBSERVATION NOTES:

CATIE, Turrialba, Cartago, Costa Rica, Latitude 9.905270154, Longitude -83.76970723, at meters elevation.

Cerro Nara, Londres, Santa María, Costa Rica, Latitude 9.449427787, Longitude -84.16521999, at 800 meters elevation.

Trail near Rancho Quemado, Osa Peninsula, Costa Rica, Latitude 8.668424387, Longitude -83.50529271, at 400 meters elevation.

Rafiki, San José Province, Pérez Zeledón, Costa Rica, Latitude 9.509429684, Longitude -83.90862117, at 168 meters elevation.

GINGERSRUS CATALOG LISTING:
Costus glaucus is named for the whitish "glaucus" covering on the new shoots, bracts (usually) and other vegetative parts, but it is not the only Costus that ever has that appearance. It is closest to Costus laevis and I have sometimes gotten them confused in the wild. What distinguishes C. glaucus besides the glaucus is the longer lobed ligules, over 15 mm and up to 55 mm. It is also usually much taller, up to 20 feet tall and with straighter stems.

It has large leaves and a colorful flower against the green bracts. I have usually found it growing in sunny areas and it should do well in full to part sun. I have not tested this for hardiness and assume it would only be hardy in frost free areas.