Gingersrus Database Taxon ID 7623
CURRENT NAME: Costus sp. nov.
PROPOSED NAME: Costus antioquiensis
NAME CHANGE NOTES: New species published March 22, 2023 in PhytoKeys 222: 75-127, from Antioquia, Colombia
FULL SCIENTIFIC NAME: Costus antioqiuensis Maas & H.Maas
STATUS : sp. nov.
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Costus antioquiensis was published March 22, 2023 in PhytoKeys 222: 75-127 by Paul and Hiltje Maas. It was recognized by Paul Maas as an undescribed species, often included with the former Costus laevis on herbarium sheets. The type specimen was collected by Maas et. al., No. 10488, and is growing in cultivation in the botanical garden in Utrecht, Netherlands. It was collected in the province of Antioquia, Colombia, from which it is named. In his description, Maas says that Costus antioquiensis is "well recognizable by adaxially oriented flowers and a ring of brown, erect and stiff hairs (hirsute) at the ligule" (often present) and " the lower leaf side and bracts often densely villose". He distinguishes this species from Costus laevis by the flower color and from Costus allenii by the differences in the indumenta.
Costus sp. nov. antioquiensis is found mainly in Colombia but some collections from Ecuador, Peru and Venezuela have been included in this new species by Dr. Maas. Most of these are found in areas of substantial rainfall and can flower anytime during the year.
I have some difficulty in determining plants are in this species unless they include that characteristic ring of stiff hairs around the ligule. The indument is described being quite variable and Dr. Maas has included some of my collections that are nearly glabrous within this new species. He says, "C. antioquiensis is highly variable in its indument. Most material has a quite dense hirsute indument all over the plant, but some specimens in the same population can be almost completely glabrous."
Several specimens of the collections that Dr. Maas has included in this species have been sampled and analyzed in a molecular phylogeny. They have all been found to be tightly clustered together in a separate clade from other species, including forms with varied indumenta:
Paul Maas' type collection (Maas 10488) has been cultivated from the seeds he collected and has flowered in Utrecht and Burgers Bush, Netherlands. I am growing in my garden a propagule from this collection (R3405) but it has not yet flowered. Dr. Maas has also determined that the following of my collections probably belong to this species:
ACCESSIONS:Click links (if any) to see details of individual collections. R3405-
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