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): 159-162, fig. 3-4. 2022 [21/01/2022].

Distribution : Apparemment endémique du nord-est de la Guyane, connu de la montagne de Kaw, des Trois Pitons, de la Grande montagne Tortue, de la région des Nouragues et d'une localité isolée plus à l'ouest sur le Sinnamary; sous-bois, 90-400 m (Lachenaud et al., Phytotaxa, 531(3): 157. 21/01/2022).

Ecologie : Floraison en début de saison des pluies (XI-XII), fruits mûrs en fin de saison des pluies (IV-VII).

Taxonomie : D'après Lachenaud et al. (Phytotaxa, 531(3): 161-162. 21/01/2022): "This species is similar to R. itoupensis, described below; the two are remarkable in the genus by their deeply laciniate bracts and stipules (shallowly laciniate in most other species), ± pendulous inflorescences, well-developed calyx tube, and bipartite disk (the disk in Rudgea species is usually entire). It differs from R. itoupensis by its larger and narrower bracts that long exceed the calyces, and its longer corolla tube (Table 2). The two species also have different geographical and altitudinal ranges. In view of their stipule morphology and fruit colour, these species probably belong to the informal “lanceifolia clade” defined by Bruniera (2015).
Another species resembling R. glomerulata is Palicourea yneziae C.M.Taylor (Taylor 2015: 81) [Syn. Rudgea mexiae Standley (1936: 165)] from Peru and southern Colombia. This species was recently transferred from Rudgea to Palicourea, although it is unusual in the latter genus – especially due to its fimbriate stipules – and its placement there is provisional (Taylor 2015: 59–60). Its stipules, bracts and calyces are quite similar to those of R. glomerulata, although the leaf venation, disk, and fruit colour are different in both taxa (Table 2). In the absence of phylogenetical analysis including these species, it is unclear whether the resemblance between them is due to convergence or indicative of an affinity.
There is also some resemblance between R. glomerulata and R. lanceifolia, especially in the shape of the stipules, but the differences are numerous: R. lanceifolia is a taller plant 3-10 m high, with more strongly ascending secondary leaf veins, an erect and usually branched inflorescence, entire or shortly dentate bracts, a calyx divided almost to the base, a usually longer (17-80 mm) corolla tube that is pubescent on both sides, and fruits dark red when immature and black when mature, crowned with an entire markedly accrescent disk 2-3 mm long and 5-10 mm in diameter.
The inflorescences of Rudgea glomerulata are often capitate, but may have short ramifications, especially at the fruiting stage, as the rachis might expand after anthesis. It is not known whether the flowers are heterostylous; the only open flowers seen (on the type) are short-styled.
Two collections, one from the Pakaraima Mountains in Guyana, K.M. Redden, R. Williams, C. Perry, C. Paul & M. Lyle 1927 (P [P01019851]) and the another from Araracuara in Colombia, H. Vester & A. Matapi 754 (L.4195512]), very closely resemble R. glomerulata in characters of the bracts, inflorescences and stipules, as well as in leaf shape and venation, but have a hirsute (rather than appressed) indumentum on the petioles and lower surface of leaf veins. The former specimen also has a much shorter peduncle, while the latter appears to have an erect inflorescence. More material is required to decide whether these collections are conspecific or not with R. glomerulata."

Type : Guyane française, montagne de Kaw, route de Kaw, p.k. 46, 4°33’N, 52°09’W, 14/12/1986, fleurs. J.J. de Granville 9075 (HT: MO-2365274; IT: CAY079168, P03985332, U0130743).
Guyane française, montagne de Kaw, extrémité est, versant sud, 03/11/1985, fleurs tombées. J.J. de Granville 8245 (PT: CAY, MO).
Guyane française, montagne de Kaw, Montagne Favard, 20/04/1984, fruits. J.J. de Granville 6880 (PT: CAY, MO).
Guyane française, montée du Pic des Trois Pitons, 09/06/1980, fruits. C. Moretti 1166 (PT: CAY, P).
Guyane française, estuaire de l’Oyapock, entre le village de Petit Toucouchi et la montagne des Trois Pitons, 20/01/1981, fleurs tombées. J.J. de Granville 4279 (PT: CAY, P, U).
Guyane française, Eastern Plateau of Montagne Tortue, 11 km WNW of Approuague River, 4°18’N, 52°22’W, 12/06/1988, fruits. C. Feuillet 10045 (PT: K).
Guyane française, Arataye (affluent de l’Approuague) au saut n°1, rive droite, 10/02/1969, jeunes fruits. R.A.A. Oldeman B-2127 (PT: CAY).
Guyane française, Fleuve Arataye, Saut Pararé, 27/07/1984, fruits. B. Riéra 659 (PT: CAY).
Guyane française, Nouragues, 13/05/1985, fruits. A. Cockle 101 (PT: CAY).
Guyane française, Station des Nouragues, 4°03’N, 52°42’W, 22/11/1989, boutons. G. Cremers 10928 (PT: CAY).
Guyane française, forêt sur la rive gauche de l’Arataye, à environ 2 km du Saut Pararé, 14/02/1969, jeunes fruits. J.J. de Granville 82 (PT: CAY, P).
Guyane française, Station des Nouragues, 4°03’N, 52°42’W, 23/02/1991, jeunes fruits. J.J. de Granville 11173 (PT: CAY, MO).
Guyane française, Station des Nouragues, 4°03’N, 52°42’W, 06/1989, fruits. D. Larpin 643 (PT: CAY).
Guyane française, Nouragues Field Station, 4°05’N, 52°40’W, 27/02/2002, jeunes fruits, S.A. Mori, F. Blanchard & T.A. Lobova 25483 (PT: CAY, NY, P).
Guyane française, station des Nouragues, bassin de l’Arataye, 4°03’N, 52°42’W, 11/07/1989, fruits, D. Sabatier & M.-F. Prévost 2533 (PT: CAY, P, U).
Guyane française, D.Z. de Crique Jupiter, bassin du Sinnamary, 24/04/1991, jeunes fruits. J.J. de Granville, C. Roesel & L. Brothers 11497 (PT: CAY).