Monographs Details: Psychotria mazaruniensis Standl.
Authority: Maguire, Bassett. 1972. The botany of the Guayana Highland--part IX. Mem. New York Bot. Gard. 23: 1-832.
Family:Rubiaceae
Discussion:

Cephaelis jenmani Wernh., Jour. Bot. 52: 313. 1914, not Psychotria jenmanii Urb. Symb. Ant. 7: 440. 1913.

This taxon differs from P. transiens Wernh. and P. appuniana Steyerm. in having the central ray of the inflorescence prolonged beyond the two lateral rays and branching into three units of which the central one is again longer, resulting in a subracemose instead of umbellate or ternate, more or less equal-rayed inflorescence of the other species noted. As in P. tepuiensis, what are apparently two bracteoles subtending one flower is actually, at least in the beginning before rupturing, one bracteole which is deeply parted or deeply bilobate. The lobes themselves are ciliate on both sides. This bracteole is surrounded at its base on each side by the subamplexicaul sub-orbicular-ovate, subacutely obtuse bract. Within a head of flowers, one bract subtends one side, usually the outer, of the flower and one appressed, deeply two-parted, carinate smaller bracteole subtends the other side. Usually only the outermost flowers are thus subtended by bract and bracteole, but those in the center of the head often lack a bracteole. Usually 5-10 flowers are found within one head.

Sandwith (Kew Bull. 1949: 260-261. 1949) pointed out that Cephaelis jenmanii Wernh. and Psychotria mazaruniensis Standi, were synonymous, as well as showing the similarities and differences existing between this and related taxa.