Commelina guyanensis Klotzsch ex Seub.

Commelina guyanensis Klotzsch ex Seub. (Seubert in Martius 1855: 262). – Commelina guianensis Klotzsch (Klotzsch in Schomburgk 1849: 1064), nom. not effectively published. Syn. nov.

Type material

GUYANA • s.loc., In swampy areas of the savannah and on the banks of rivers; s.dat.; fl.; M. R. Schomburgk 387; neotype: P [P01795521]!, designated here .

Accepted species

Commelina diffusa Burm.f.

Nomenclatural remarks

No specimens were cited by either Klotzsch (Schomburgk 1849) or Martius (1855). However, while visiting the P herbarium, we came across a specimen (P 01795521) that perfectly matches the diagnoses provided by both authors. Furthermore, the label is from the same expedition as P 00752552, which is annotated as being the type of C. platyphylla Klotzsch ex Seub., which shares the same publication record as C. guyanensis . Therefore, we designate this specimen as the neotype for C. guyanensis, also fixing its application as conspecific with C. diffusa .

Remarks

Commelina guyanensis Klotzsch ex Seub. has been traditionally regarded as a synonym of C. rufipes . Klotzsch’s original description (Schomburgk 1849) was done solely in German, lacking a Latin diagnosis or description, making the name not effectively published. However, the German diagnosis described the species as a perennial herb growing on swampy savannah and riverbanks, which prevents it from being conspecific with C. rufipes (a species from the non-flooded understory of rainforests). Later, Martius (1855) finally provided a Latin diagnosis, which characterised the species as having glabrous stems, leaf-sheaths margin setose with light brown hairs, leaf-blades lanceolate with acuminate apex and vinaceous veins, inflorescences subterminal and “short-pedunculate” [sic], spathe conduplicate (i.e., base free), “pedicels 2” (i.e., with 2 developed cincinni) with the upper one hirtellous and “sterile” [sic], capsules glabrous, and seeds free. These characters make it impossible for this name to represent a synonym of C. obliqua, let alone C. rufipes . However, both diagnoses confidently place the species in the C. diffusa group. As aforementioned, the selected neotype is conspecific with the current circumscription of C. diffusa . Thus, this name is excluded from the synonymy of C. rufipes and placed under the synonymy of C. diffusa .