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Datasheet for Costus zamoranus

Plant Datasheet for Costus zamoranus

CLICK HERE for a detailed botanical description and identification key for this species (opens in new window).

BOTANICAL NAME: Costus zamoranus
FORMAL SCIENTIFIC NAME: Costus zamoranus Steyerm.
STATUS :Accepted
CONTINENT: Neotropical

This is an accepted neo-tropical Costus species first described in 1963. It is very similar to Costus amazonicus and can be distinguished only by the shorter calyx. It is described as a basal flowering plant whereas C. amazonicus can be either terminal or basal.

It was assessed as "Vulnerable" on the IUCN Red List in 1997. I completed an updated assessment in 2014 and maintained its status Vulnerable, but this mostly based on incomplete information. The assessment with further details can be found at

I had never seen this species either live or in photos until February 2015 when I went to the type locality in Valladolid as noted below. Note that the Isotype as det'd by Maas in 1970 was sterile and there was no description of the flower until his 1977 addenda. It is very difficult to tell whether collection records are correctly identified.

Vouchered at NYBG Herbarium -

Image: Available at Location: Ecuador. Santiago-Zamora. Along Río Valladolid, around Tambo Valladolid. Alt. 2000 m. Collector: J. A. Steyermark 54664 14 Oct 1943 Description: Sterile. Publication: Phytologia. 9: 339. 1963. Other: NY Specimen ID: 320357

In February 2015, I traveled to southern Ecuador to learn more about Costus zamoranus - This species is endemic to southeastern Ecuador. It is poorly described, very close to the species C. amazonicus and C. laevis, and I had never been able to find any verified photos of it, so my primary goal of this trip to Ecuador was to find this species. The only way to be sure I found the right plant was to go to the remote type location in the Mayo-Chinchipe region at the town of Valladolid. Thanks to the help of Marco Jiménez - Leon and his father Marco Jimenez, we found it there and a few other places as well. I have prepared a thumbnail sheet with the photos at Valladolid and found at

After leaving Valladolid we traveled along the road toward the community of Tapala. Most of this area was deforested but there were a few patches of forest and there we found more Costus zamoranus. We also found a terminal flowering plant with a strong affinity to C. zamoranus and other terminal plants with appendaged bracts that would place in the diverse C. aff. claviger group that is found all along the eastern foothills of Ecuador and Peru. After examining my photos and reflecting a bit, I think the terminal flowering plant, despite its lack of bract appendages, is closer to the C. aff. claviger group than to C. zamoranus. This mainly due to the apex of the stamen - an important flower part. Photos of these are at

The third place we saw this species was east of Palanda near the Rio Numbala at 925 meters. Based on our observations, this species was only found in shady areas, usually with a coarse sand base. The flowers were variable but at this location, were the most beautiful ones, a deep garnet color. My thumbnail sheet for this example of C. zamoranus can be found at

Costus aff. zamoranus Nangaritza Form - Perhaps the most interesting plant we found was this one, which fits perfectly with the description of C. zamoranus but was distinctively different from the plant found in the type local near Valladolid. It was growing in very heavy sticky grey soil of the Cord. del Condor. The bracts have a distinctive reddish margin and the nectar callus on the bracts is dark red in color. The flowers were more tubular in shape than the type, and this plant was much more clearly distinguishable from it's closest species - C. amazonicus or C. laevis. My thumbnail sheet for these plants is found at

In the Tundayme area of the Cord. del Condor at 1150 meters we found two plants, one flowering the normal basal inflorescence and one terminal, both of which were totally consistent with the type for the species at Valladolid. As with most Costus species, it seems this one also has the potential to flower both ways. Thumbnail sheet at

El Oso Road - We did find one plant that was closer to the type but located in a region far to the north which helped me better understand the range of this species. It was clear that this species only grows in the shade of forested areas, which are quickly disappearing from southeastern Ecuador. One of my objectives was to determine the threat status so I could update my assessment of this species on the IUCN Red List. Here is a short thumbnail with a few images at this location.

Collections: R3324 and R3325 at Valladolid, R3326 and R3328 along Tapala Rd., R3336 at Reserva Maycu, R3340 and R3341 in Tundayme area.


Valladolid, Zamora-Chinchipe, Ecuador, Latitude -4.412847786, Longitude -79.19436854, at 1575 meters elevation.

Tapala Road, Zamora-Chinchipe, Ecuador, Latitude -4.579577748, Longitude -79.14233948, at 1700 meters elevation.

Rio Numbala, Zamora Chinchipe, Ecuador, Latitude -4.687757226, Longitude -79.10361831, at 925 meters elevation.

Reserva Maycu, Nangaritza, Ecuador, Latitude -4.254037065, Longitude -78.6039985, at 1008 meters elevation.

Las Orquideas, Nangaritza, Ecuador, Latitude -4.251746402, Longitude -78.72274047, at 954 meters elevation.

El Oso Road, Yantzaza, Ecuador, Latitude -3.614090717, Longitude -78.66096634, at 1317 meters elevation.

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