Populations of Unonopsis guatterioides (Annonaceae) in Amazonas and Minas Gerais, Brazil, potentially represent different species: Floral scent, flower characters and pollinators revisited Gerhard Gottsberger a, * , Ilse Silberbauer-Gottsberger a , Antonio Carlos Webber b , Stefan D € otterl c a Botanischer Garten/Herbarium, Hans-Krebs-Weg, Universit€ at Ulm, 89081, Ulm, Germany b Retired from Departamento de Biologia, Universidade Federal do Amazonas, 69077-000, Manaus, Brazil c Department of Ecology and Evolution, Hellbrunnerstrasse 34, University of Salzburg, 5020, Salzburg, Austria article info Article history: Received 7 November 2017 Received in revised form 24 January 2018 Accepted 16 March 2018 Keywords: Floral scent Pollination biology Unonopsis guatterioides abstract A population of Unonopsis guatteriodes (Annonaceae) in Amazonia differs from another population in Minas Gerais by flower morphology, pollination biology and floral scent emissions. In view of the dif- ferences, we encourage more in-depth studies to reveal whether the synonymous U. lindmanii R.E. Fries should be re-established as a valid taxon for the Minas Gerais plants. © 2018 Published by Elsevier Ltd. Unonopsis guatterioides (A.DC.) R.E. Fries has the largest distri- bution of all Unonopsis species, occurring from the Lesser Antilles down to Paraguay. It is also by far the most variable and taxo- nomically problematic species in the genus (Maas et al., 2007). These authors recognized hairy forms of U. guatterioides in Central Brazil, which also would include a population studied in Uberl^ andia by Oliveira et al. (2017), and which formerly were considered a distinct species, U. lindmanii R.E. Fries. In the most recent revision of Unonopsis, the authors, however, concluded that these hairy forms fall within the variation pattern of U. guatterioides (Maas et al., 2007). In a recent publication, Oliveira et al. (2017) presented data on the floral biology, the pollinating bees, and the scent emissions of Unonopsis guatterioides, growing in a gallery forest in the center of the Cerrado biome area close to Uberl^ andia, Minas Gerais. Another population of this species has been studied earlier by Carvalho and Webber (2000) in Amazon forests close to Manaus, almost 3000 km further north. Oliveira et al. (2017) detected that the Uberl^ andia population had smaller flowers with a considerably lower number of stamens (only up to 100) than the Manaus population (172e236). The more hairy Uberl^ andia population flowered from September to November while the Manaus population flowered throughout the whole year. The most remarkable differences found were the rhythms of anthesis of this protogynous species and the pollination process. The Uberl^ andia population started its anthesis, including scent emissions, between 8 and 9 a.m., and both the pistillate and staminate stages ended at about 3 p.m. on successive days. Its pollinators are relatively small (6e9 mm) pollen-collecting bees, especially Halictidae and some Apidae. The pistillate stage flowers do not provide any resources for these bees, and are apparently visited and pollinated by deceit, whereas bees were rewarded with pollen on staminate stage flowers. On the other hand, the Manaus population initiated its pistillate stage often already at 2 a.m. or somewhat later, but always long before dawn, and finished their activity already between 8:30 to 9 a.m. The second-day staminate stage flowers shed pollen between 3 and 6 a.m. The petals dropped at 9 a.m. at the latest. The only pollinators observed visiting this Manaus population were males of Eulaema bombiformis (Euglossinae: Apidae), which is a large bee species of ca. 3 cm body length. This bee was the only pollinator and collected liquid scent (perfume) from the petals of the flowers in pistillate and staminate stage (Carvalho and Webber, 2000). * Corresponding author. E-mail address: gerhard.gottsberger@uni-ulm.de (G. Gottsberger). Contents lists available at ScienceDirect Biochemical Systematics and Ecology journal homepage: www.elsevier.com/locate/biochemsyseco https://doi.org/10.1016/j.bse.2018.03.004 0305-1978/© 2018 Published by Elsevier Ltd. Biochemical Systematics and Ecology 78 (2018) 17e20