Description originale
Lachenaud, O., Bruniera, C. & Zappi, D. 2022. Six new and a little-known species of Rudgea (Rubiaceae—Palicoureeae) from the Guianas. Phytotaxa, 531(3): 154-174.

 

Statut pour la Guyane française
Lachenaud, O., Bruniera, C. & Zappi, D. 2022. Six new and a little-known species of Rudgea (Rubiaceae—Palicoureeae) from the Guianas. Phytotaxa, 531(3): 154-174. [GF = E]

 

Date de publication : Phytotaxa, 531(3): 168-170, fig. 7-9. 2022 [21/01/2022].

Distribution : Apparemment endémique du NE de la Guyane française, connue de seulement deux collectes de la montagne de Kaw (forêt basse sur cuirasse latéritique) et de l’inselberg des Nouragues (probablement en forêt basse également). Probablement rare. En dépit de plusieurs prospections à différentes saisons sur la localité du type, O. Lachenaud n’a pas réussi à retrouver l’espèce.

Etymologie : This species is named in memory of the Belgian botanist Bernard Jadin (1948–2012), collector of the type and of many other French Guianan plants, together with his wife Frieda Billiet - who is remembered in Philodendron billietiae Croat (1995: 24).

Taxonomie : D'après Lachenaud et al. (Phytotaxa, 531(3): 168. 21/01/2022): "Rudgea jadinii resembles R. graciliflora, from which it differs by the glomerulate inflorescence, flowers with anthers and style both included, and calyx lobes 1.5–2.5 mm long, while R. graciliflora has shortly branched inflorescences, distylous flowers with either style or anthers exserted, and the calyx truncate or with lobes < 1 mm long. The corolla tubes of R. jadinii are 6.5–10 cm long, which are much longer than in specimens of R. graciliflora from the Guianas, which are 2–5.2 cm long and represent the typical form of the species. However, some collections of R. graciliflora from western Amazonia have the corolla tube length comparable to that of R. jadinii. These have been originally described as R. klugii Standley (1936: 164); their status may have to be re-assessed, but this is outside the scope of this paper. Rudgea graciliflora belongs to the informal “lanceifolia clade” (Bruniera 2015) which includes species from the Guianas and the in Amazon basin, and R. jadinii probably belongs there as well.
It is not known whether R. jadinii is heterostylous; the only flowers seen have the style and anthers both included, the latter well above the former."

Type : Guyane française, route de Kaw, PK 33, sentier vers les grottes, 04°33’N 52°13’W, 04/12/2000, fleurs. F. Billiet & B. Jadin 7459 (HT: CAY014902 [Rudgea sp., det. P.G. Delprete, 2011; Posoqueria gracilis (Rudge) Roem. & Schultes, det. P.G. Delprete, 2008; Tocoyena sp., det. F. Billiet, 2000]; IT: BR000000907386).
Guyane française, station des Nouragues, entre les croisements H XXII et I XXII, 27/12/1988, fleurs. D. Loubry 100 (PT: CAY042845 [Rudgea sp., det. P.G. Delprete, 2010; cf. Coussarea, det. P.G. Delprete, 1998; Posoqueria sp., det. D. Loubry, 1988]).