The genus Psychotria is found world-wide in tropical regions, and is one of the largest genera of flowering plants (in number of species) in the world. The information here gives a general overview of the systematics and morphology of this genus, and detailed information about the Neotropical species. The information presented for the Neotropical species is for Psychotria sensu stricto. For more information about Paleotropical Psychotria, see the Madagascar Catalogue page for this genus (go to upper right of web page and click on "Chose Project", then choose "Madagascar").
The pantropical tribe Psychotrieae of the Rubiaceae belongs to the subfamily Rubioideae, and includes a large proportion of the 13,800+ species of this family. This tribe has recently been separated into two subtribes by some authors, and more often into two tribes (e.g., Razafimandimbison et al., 2014), the Psychotrieae and the Palicoureeae. Since its desdription the genus Psychotria has generally been circumscribed to include 1000-2000 species that are characterized by small white flowers with valvate corolla lobes, ovules that are solitary and basal, and drupaceous fruits with generally 2 pyrenes. Untel very recently most authors circumscribed Psychotria based mainly on flower form, and separated a number of species with distinctive characters into separate genera. This left Psychotria to a large extent diagnosed by widespread, apparently plesiomorphic features of its tribe. It was often recognized that this circumscription was probably too broad; this broad circumscription has been referred to in recent literature as "Psychotria sensu lato", or "Psychotria s. lat." Recent studies using molecular data (Nepokroeff et al., 1999; Andersson, 2002) showed that Psychotria s. lat. includes too many species groups, with a number of these species groups better treated as separate genera while some separate genera are better included in Psychotria. Genera of significant size that have been recently separated from Psychotria include the pantropical Margaritopsis (Andersson, 2001) and the neotropical or perhaps pantropical
Carapichea (Andersson, 2002). Several studies have found a number of traditionally recognized genera from Madagascar, Asia, the Indian Ocean, and the Pacific region are nested within the Psychotria clade, such as Amaracarpus Blume, Straussia A. Gray, Psathura Comm. ex Juss., Hydnophytum Jack, Myrmecodia Jack (Andersson, 2002; Razafimandimbison et al., 2014).
One group that has been particularly confused with Psychotria is the Neotropical genus Palicourea. Palicourea and several other groups recenlty separated from Psychotria belong to the separate Palicoureeae clade or tribe, not the clade with the core species of Psychotria. In the Neotropics, two large species groups have long been recognized in Psychotria, which have been treated under different names. One of these groups corresponds to Psychotria s. str., and has been called Mapouria Aubl. (Mueller, 1881) or Psychotria subg. Psychotria (Steyermark, 1972; Taylor, 1996). The other group includes more species, and has been called Psychotria (Mueller, 1881) or Psychotria subg. Heteropsychotria (Steyermark, 1972). The name Mapouria is a synonym of Psychotria s. str. , and is based on a type from South America; this name has sometimes also been used for species of Psychotria s. str. from Madagascar, but those are apparently not closely related to the South American species of Psychotria. The species that have been included in Psychotria subg. Heteropsychotria all belong to the Palicoureae clade or tribe (Nepokroeff et al., 1999; Taylor, 1996; Razafimandimbison et al., 2014). Several of these species have recently been re-classified in separate genera of Palicoureeae, Carapichea,
Coccochondra, Margaritopsis, and
Notopleura. Of the remaining species of Psychotria subg. Heteropsychotria, a few were incorrectly classified here and actually belong to Rudgea Salisb. (Taylor, Bruniera, & Zappi, in prep.). and the rest belong to Palicourea and are being transferred to that genus seciton by section. The previously recognized genus Cephaelis is a synonym of Palicourea and most of its species now belong to this genus, though some of its species were incorrectly classified here and belong to various other genera of Rubiaceae.
In the Neotropics, Psychotria s. str. can be recognized by the combination of generally caducous stipules that expose a ring of persistent or slowly deciduous colleters when they fall, fruits that are red at maturity, and plant specimens that are gray, brown, reddish brown, or blackened when dry; vs. (in general) in Palicourea stipules that are generally persistent or if deciduous then do not expose a ring of persistent colleters, fruits that may pass through a red stage but are usually (though not always) blue, black, or white at maturity, and plant specimens that are green or grayish green when dry.
Author: C.M. Taylor.
The content of this web page was last revised on 23 July 2014.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml