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Datasheet for Costus amazonicus subsp. amazonicus

Plant Datasheet for Costus amazonicus subsp. amazonicus


PLANT FAMILY: Costaceae
BOTANICAL NAME: Costus amazonicus subsp. amazonicus
FORMAL SCIENTIFIC NAME: Costus amazonicus (Loes.) J.F. Macbr.:
STATUS :accepted
CONTINENT: Neotropical
SYNONYMS:


BOTANICAL NOTES:
Costus amazonicus is described by Paul Maas as being a rather stout plant, flowering either terminal on a leafy stem or basal on a separate leafless shoot. Bracts are green on exposed part, red covered part and not appendaged. Flowers are the open labellum type. Subspecies amazonicus is distinguished from subsp. krukovii by having puberulous corolla lobes and the margins of the bracts being fibrous. It is distributed in amazonian Ecuador and Peru up to 1100 meters.

Costus amazonicus (Loes.) J.F. Macbr.: subsp. amazonicus - Holotype: 1924 by Tessmann 4903, originally as C. malortieanus var. amazonicus, from Peru, Loreto, Maynas, along the lower Morona River (should be Rio Santiago), near the confluence with the Maranon River. (Ost. Peru: Stromgebiet des Maranon von Iquitos aufwärts bis zur Santiago- Mündung am Pongo de Manseriche. ca. 7 30' W.) Basin of the Maranon from Iquitos up to Santiago mouth at Pongo de Manseriche.

In February 2015 I returned to southeastern Ecuador and found many of these plants scattered throughout the area. This species is common in the Zamora Chinchipe region, usually found at the lower altitudes of the area (800-1200 meters) and distinguishable from similar species by the fibrous margins of the bracts. It flowers both at the base and terminally. The vegetative parts are usually very hairy and the stems tend to be thick and spongy feeling. My thumbnail sheet with some photos of the plants seen on this trip can be found at http://www.gingersrus.com/images/R3335

ACCESSION NOTES:
R3077 is the 2007 Guayzimi collection, previously thought to be C. zamoranus, now transferred here. In Maas' 1972 monograph regarding C. zamoranus he states that "The position of this species is rather uncertain as nothing is known of its floral structure. It seems closest to C. amazonicus, from which it can only be distinguished by its calyx." The calyx in C. zamoranus is described as 10-13(-15) mm long, glabrous to sparsely minutely puberulous lobes deltate to shallowly triangular 2-3 mm long. In 1977 he added to the description of C. zamoranus, excluding some Colombian specimens, and this plant thus departs from matching as well. C. zamoranus is described as less hairy with a glabrous calyx and bracteole and with red bracts. The calyx in C. amazonicus subsp. Amazonicus is described as (11-)17-19 mm long and 10-15 mm wide, densely puberulous to glabrous (probably in subsp. Krukovii), lobes shallowly triangular to deltate 1-5 , long. The bracteole in C. amazonicus is described as (20-) 27-35 mm long and puberulus to glabrous (again, probably only in krukovii) and the bracts as green in the exposed part and red in the covered part. In examining and measuring the calyx in this plant, it is 15-16 mm long and 14 mm wide, the bracteole is 26 mm long and the bracts are green. I now am convinced this plant more closely matches the description of C. amazonicus subspecies amazonicus than C. zamoranus. R3077 has been vouchered at the UC Berkeley, Jepsen Herbarium, UC2045838.R3198 was collected in 2009 near the Rio Pastaza in Ecuador and previously listed as undetermined. In 2014 this collection came to flower and clearly fits the description of this subspecies. R3198 has been vouchered at the UC Berkeley, Jepsen Herbarium, UC2045798.R3335 from the Rio Yacuambi area of Ecuador did not survive.

OBSERVATION NOTES:

Rio Yacuambi area, Zamora-Chinchipe, Ecuador, Latitude -3.8495, Longitude -78.86594, at 942 meters elevation.

Rio Pastaza, Morona-Santiago Province, Ecuador, Latitude -1.913, Longitude -77.827, at 700 meters elevation.

Guayzimi, Nangaritza, Ecuador, Latitude -4.065, Longitude -78.695, at 1100 meters elevation.

GINGERSRUS CATALOG LISTING:
Costus amazonicus This plant was collected in the Rio Nangaritza area of southeastern Ecuador. I thought it was the species C. zamoranus, but after further research and study of the detailed characters I have now concluded this to be the species Costus amazonicus subspecies amazonicus. Further discussion of this is on my main website at http://www.gingersrus.com/DataSheet.php?PID=7467.

The plant matures to about 4 feet tall and I have had it flower both basally and terminally, with green bracts and creamy white flowers with red stripes on the labellum. It has not been tested for hardiness but probably needs to be protected from temperatures below 40 degrees Farhenheit.


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