Found again: the extremely rare Codonorchis canisioi (Orchidaceae: Codonorchideae) reappears after being missing for 78 years

Abstract

To date, the endangered terrestrial orchid Codonorchis canisioi was only known from two collections at its type locality. This plant has not been collected since 1935 and is currently considered as Critically Endangered in the Brazilian list of threatened flora. We recently found two small populations about 174 km from the type locality. We thus seized the opportunity to make a complete record of morphological traits, aiming to fill the gaps of the short and non-illustrated protologue. Plant, flower (including details of column and pollinarium) and fruit features are here illustrated and discussed in detail. Overall, plant and flower features are similar to those of the widespread Patagonian C. lessonii. Yet, both species can be separated by a number of vegetative and floral features. Female Augochlorine Halictidae bees were recorded as pollinators. Fruits mature quickly (15–19 days after pollination). Plants wither by middle October, resting underground as very small (3–5 mm diameter) roundish tubers. The two newly found populations are in privately owned areas and prone to both fire and cattle grazing. Due to the small size of each population (estimated in less than 200 individuals), it is likely that this species would still be considered as CR (Critically Endangered) when formally and properly surveyed under the IUCN criteria. Since plants are small and strongly seasonal, more field surveys are necessary to locate other potentially overlooked populations.