Gingersrus Database Taxon ID 4012Dimerocostus appendiculatusOLD NAME: Dimerocostus strobilaceus subsp. appendiculatus NEW NAME: Dimerocostus appendiculatus NAME CHANGE NOTES: Former subspecies appendiculatus now becomes a recognized species. A revision to Neotropical Costaceae, published January 6, 2026 in Blumea Volume 70, Number 1, 2026, pp. 1-115 FULL SCIENTIFIC NAME: Dimerocostus appendiculatus (Maas) Maas & H.Maas, proposed comb. nov. STATUS : stat. nov. CONTINENT: Neotropical FIELD OBSERVATIONS:(If field observations are available, you can click on the link to open in a new window.) FIELD OBSERVATIONS PHOTOS:(If photos are available, you can click on the link to open in a new window.) GOOGLE PHOTO ALBUM SYNONYMS: - Dimerocostus strobilaceus subsp. appendiculatus Maas (1972) BOTANICAL NOTES: This former subspecies of D. strobilaceus are now published as separate species in Blumea: Biodiversity, Evolution and Biogeography of Plants, 70(1), 1-115. doi:10.3767/blumea.2026.70.01.01. Dimerocostus appendiculatus can easily be confused with Dimerocostus argenteus . Both species have yellow flowers and appendixed bracts but the appendages to D. argenteus are usually not persistent, decaying as the inflorescence matures. The persistent leafy appendages to the bracts is the primary character that distinguishes D. appendiculatus. Based on field studies in Peru and Bolivia, I determined that Dimerocostus has two very different forms of flower structure. There is the type of flower found in D. strobilacious that has a broad, flat labellum, and the other type of flower found in D. argenteus that has a smaller labellum with the upper corolla lobe forming a distinctive "hood" over the labellum. Dr. Maas has adopted this distinction in his key to Dimerocostus species. The flowers of D. appendiculatus tend to be intermediate between the two types - not fully "hooded", but not quite as broad and flat as the typical D. strobilaceus flower. Dimerocostus appendiculatus is found in Amazonian parts of Peru and Colombia with most of the collections found in the region of the Amazon River between iquitos and Leticia. It flowers year round. The type specimen for this subspecies was collected at Hacienda Indiana near the mouth of the Rio Napo in Dept Loreto, Peru. In 2008 I photographed a Dimerocostus within 50 or so km from that location at the San Rafael Indigenous village on the Amazon River. The photos I took are shown on this page and are believed to be this subspecies, now changed to a separate species. Unfortunately, I did not appreciate that I was seeing something special and did not take many detailed photos, and did not check the undersides of the leaves. The seeds that were collected germinated but did not survive here. A thumbnail page showing photos of this plant can be found at http://www.gingersrus.com/images/P4012 In 2022 I returned to Iquitos and spent several days at the reserves (Madre Selva and Santa Cruz) established by Project Amazonas. This species is quite common at both reserves and I was able to study them in detail. I found that another trait for the species is a very long caudate acumen, like a long filament up to 80 mm at the apex of the leaves. I have not seen that trait in any other species in Costaceae.  Long, caudate, acuminate apex on D. appendiculatus DNA has been extracted from a sample of this species that was collected near Iquitos. In a 2020 phylogeny of Dimerocostus it was found to be in a separate clade, closest to the white flowering form of Dimerocostus strobilaceus.
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