Psiadia glutinosa (Lam.) Willd.

1. Psiadia glutinosa (Lam.) Willd. View in CoL ( Fig. 1)

Species Plantarum, ed. 4, 3: 2384 ( Willdenow 1803). — Conyza glutinosa Lam., Encyclopédie View in CoL méthodique. Botanique 2(1): 89 ( Lamarck 1786). — Typus: Madagascar • “de l’Isle de France”; s.d.; Anon. s.n.; lectotype ( designated here): P-LA[P00356056]!; isolectotypes: MPU[MPU014968] image!, P-LA[P00356055]!) ( Fig. 1).

Solidago viscosa Schrad. View in CoL , Sertum hannoveranum 1 (fasc. 1): 12, t. 6 ( Schrader 1795), nom. illeg., non Lamarck (1779). — Psiadia glutinosa Jacq. View in CoL , Plantarum rariorum horti caesarei schoenbrunnensis 2: tab. 152 ( Jacquin 1797), nom. inval. — Typus: Iconography; lectotype ( designated here): Schrader (1795: tab. VI, sub Solidago viscosa View in CoL ).

Psiadia altissima var. latifolia Humbert, Mémoires de la Société View in CoL linnéenne de Normandie 25: 50, 175, 284 ( Humbert 1923). — Typus: Madagascar • Anosy Region [Prov. Toliara], Fort-Dauphin ; 1897; G. Paroisse 3; lectotype ( designated here): P[P02488135] image!; isolectotypes: P[P02488129] image !) • Atsimo-Andrefana [Prov. Toliara], Andrahomana ; XI.1900; Ch. Alluaud 113; remaining syntype: P[P02488090] image !

ICONOGRAPHY. — Schrader (1795: tab. VI, sub Solidago viscosa ); Jacquin (1797: tab. 152); Humbert (1960: 305, fig. LXI: 25-31).

DISTRIBUTION. — Endemic to southeastern Madagascar.

NOTES

Some authors attributed to Nikolaus Joseph von Jacquin (1727-1817) the authority of Psiadia glutinosa (e.g. Humbert 1960), but this is an error because Jacquin’s name was not validly published under ICN Art. 38.5 ( Turland et al. 2018). Since he cited the name Solidago viscosa Schrad. [1795] as a synonym, an illegitimate name under Art. 53.1 but validly published, both names become homotypic, and therefore, the requirement (b) for accepting the descriptio generico-specifica provided by Jacquin as validly published is not fulfilled.

Two specimens of Conyza glutinosa Lam. are kept at P-LA. One of them (P00356056), which is selected here to serve as lectotype, bears a label handwritten by André Thouin (1747-1824), the Chief Gardener of the Jardin du Roi in Paris at that time, with the following information: “ C. glutinosa L. / nouvelle en 1770 / de l’Isle de France ”. The second specimen at P-LA (P00356055) bears a short description in Lamarck’s handwriting but is clearly part of the same gathering and considered here as an isolectotype. Another duplicate of this collection is extant in Thouin’s herbarium now at MPU (MPU014968) (see Callmander et al. 2019).

Psiadia glutinosa View in CoL is unknown on l’Île de France, now Mauritius ( Scott 1993). Indeed, it is considered as endemic to Madagascar ( Humbert 1960), which suggests that the provenance of the seeds planted in the Jardin du Roi was mistakenly annotated. Confusion between Madagascar, Réunion, and Mauritius was not rare at that time. Those islands were often visited during the same voyage, leading to errors in the origin of the plants cultivated in France. Another case exemplifying this is the specimen of Psiadia glutinosa View in CoL kept at B-W (B-W 16745 -01 0), where the label on its blue cover indicates “Habitat in insula Burbon [Bourbon]”, now Réunion, where the species is unknown. This uncertainty probably also explains the fact that this species was omitted by Humbert in his first treatment of the Malagasy Compositae ( Humbert 1923). Later, he treated P. glutinosa View in CoL as an accepted species ( Humbert 1960) and placed his P. altissima var. latifolia Humbert View in CoL in synonymy.

Two syntypes were cited in the protologue of Psiadia altissima var. latifolia View in CoL : Alluaud 113 and Paroisse 3. The second consists of two specimens kept at P, P02488135 being the most complete and informative. This is therefore selected as lectotype.

Psiadia glutinosa View in CoL belongs to a taxonomically complex assembly of taxa centered around P. altissima View in CoL (synonym of P. madagascariensis View in CoL , see below) along with P. coarctata (Humbert) Humbert View in CoL , P. serrata (Humbert) Humbert View in CoL , and P. angustifolia (Humbert) Humbert. View in CoL These taxa are currently treated as five distinct species ( Humbert 1960; POWO 2025), but Humbert (1923) initially treated them as infraspecific taxa of P. altissima View in CoL , except for P. glutinosa View in CoL that was omitted as already explained above.