PLANT FAMILY: Costaceae
BOTANICAL NAME: Costus spiralis Green Bract form from Peru
FORMAL SCIENTIFIC NAME:
These plants are similar to Costus spiralis but with green bracts instead of red bracts. I have seen the green bracted form in Hawaii at Waimea Arboretum and the National Tropical Botanical Garden. Waimea 75S151 - Seed collected by Plowman in Peru, Dept. Ayacucho, Prov. La Mar, Near San Francisco, alt. 3200 ft., described as herb 4 m, flowers red. Also, WA 76p303 - parent wild collected by Plowman in PERU, Junin, Tarma, Puente Perene above Rio Perene at 715 m in 1976.
A plant I found along the road near Atalaya, Peru comes closest to Costus spiralis, but it has green bracts (in the exposed part) instead of red bracts. This one is glabrous on both sides of the leaves. I also saw it growing along the road back to Cusco up to about 1500 meters. It is identical to two Tim Plowman collections from the 1970's that I found at NTBG and Waimea in Hawaii. The flowers are clearly like the C. spiralis I found at Cristalino, Brazil, so I have placed it in that species. Maas noted in his 1977 monograph that Costus spiralis "appears to be quite heterogeneous and may need to be split up." My thumbnail sheet for this plant can be found at http://www.gingersrus.com/images/R3256.
A plant found at Laguna Venecia, near Tarapoto, San Martin, Peru, grown from seeds and distributed to John Mood in Hawaii flowered in 2014. Based on his photos it is determined as Costus spiralis in the green bract form seen at Atalaya and several photos on the internet from Peru. This form is glabrous on the upper side of the leaves but is pubescent on the undersides.
UPDATE: In November 2016 I traveled to central Peru in the area around Tingo Maria, Dept. Huanuco to visit the type locality of three species: Costus laevis, Costus scaber and Dimerocostus argenteus, which were collected and described over 200 years ago by HipÃ³lito Ruiz. At the poblado Cuchero, where Ruiz had stayed for several months I found a plant that best fits the currently described species Costus guanaiensis var. tarmicus, and has sometimes been attributed to an undescribed species Costus aff. claviger. The plant found at Cuchero matches very closely to the written description by Ruiz of a plant he named as Costus laevis. The entire situation is further complicated by the fact that the holotype of his Costus laevis is yet a different plant, also found in this region, that most closely fits to the currently described Costus spiralis in this same green bract form. I suspect that the Cuchero plant is the same plant form as was collected, named and described as Costus tarmicus, from La Merced in Junin Dept. of Peru. Further research is needed to sort all this out, but the report of my findings is published in the December 2016 quarterly Bulletin of the Heliconia Society International.