Plant Datasheet for Costus claviger

In 1972 Maas stated C. claviger is close to C. guanaiensis and C. juruanus (a species he later dismissed). He distinguished it from C. guanaiensis by saying the bract appendages are fragile instead of rigid as in C. guanaiensis. He also said it has yellow-red flowers instead of reddish-white flowers. Further distinguished by having a longer ligule and often reddish leaves. He said C. claviger has two forms: a terminal flowering form from rain forests and varzea forests of Colombia, Brazil and Peru. And a basal flowering form from the Guianas occuring on granitic outcroppings or rarely sand to clay forest floors.

Then in his 1977 monograph, Maas seems to exclude the terminal flowering plants from this species, mentioning only the Guianan basal flowering plant and dividing the whole group into four species as follows:
C. claviger, the basal flowering plant from the Guianas with a truncate to slightly two-lobed ligule 5-15 mm long,
C. erythrophyllus (newly described by Maas in 1976), with deeply lobed ligules 10-38 mm long (seePID3431) ,
C. varzearum (newly described by Maas in 1976), with two-lobed ligules 20-30 mm long (PID3108), and
C. aff. Claviger (not formally described or given a species name) with short truncate ligules 2-5 mm long (PID7425).

The herbarium sheet for the holotype (the basal flowering plant) has the description: "Fleur jaune striée de rouge en dedans. Locality not given but this was part of an expedition Guyane Francaise, Mission R. Benoiost 1913-14. The type species for C. claviger is from French Guiana, and is assumed to be the shorter, basal flowering form.

I have seen two forms that I am fairly confident are true examples of the basal flowering species Costus claviger. A third form from Colombia (R3306 and R3307) could also be Costus claviger, but I believe it is closer to Costus erythrophyllus.

ACCESSION NOTES:
R2725 - I received this plant from Tom Wood (origin unknown) tagged as Costus claviger and it seems to match fairly well to Maas' description of this species as updated in 1977. It is a short plant with very thin stems and distinctive purplish ligules about the length described by Maas. It has creamy yellow flowers and green leafy appendages to the bracts. It is a basal flowering plant. It only flowered for me once and I did not photograph or measure the separate flower parts.

R3219 is a basal flowering plant collected in Guyana, Iwokrama. This collection has been vouchered at the UC Berkeley, Jepsen Herbarium, UC2045813. This plant was found growing in the Iwokrama Mountaiuns, on forest floor near the river and was distinguishable by the plicate leaves from the other form of Costus that was found in the area growing on boulders. There were no flowers or inflorescence on the plant and only the one plant like this was seen. In 2014 this plant flowered and is determined to be C. claviger, in the "standard" basal flowering form as described by Paul Maas.

OBSERVATION NOTES:

Iwokrama Gorge, Iwokrama Mtns, Guyana, Latitude 4.35, Longitude -58.796, at 500 meters elevation.