Psiadia lucida (Cass.) Drake

Calvo, Joel & Callmander, Martin W., 2025, Novelties in Psiadia Jacq. ex Willd. (Compositae) from Madagascar and Comoros, Adansonia (3) 47 (22), pp. 353-362 : 356

2. Psiadia lucida (Cass.) Drake ( Fig. 2)

Histoire physique, naturelle et politique de Madagascar 36: t. 488. ( Drake del Castillo 1903). — Glyphia lucida Cass. , Bulletin des sciences, par la Société philomatique de Paris 1818: 141 ( Cassini 1818). — Glycyderas lucida (Cass.) Cass., Dictionnaire des sciences naturelles 59: 63, 74 ( Cassini 1829). — Typus: Madagascar • s.l.; s.d.; P. Commerson s.n.; holotype: P-JU[P00667271]!; isotypes: G[G00618076]!, P[P02475737]!; probable isotype: P[P02475738] image! ( Fig. 2).

Microglossa sessilifolia DC. , Prodromus systematis naturalis regni vegetabilis 5: 320 ( Candolle 1836). — Typus: Madagascar • s.l.; 1835; W. Bojer 6; lectotype ( designated here): G-DC[G00455785]!; isolectotype: K[K000273809] image!) • s.l.; s.d.; J. Forbes s.n.; remaining syntypes: BM[BM000903879] image!, G-DC[G00455808]!

Conyza flexilis DC. , Prodromus systematis naturalis regni vegetabilis 5: 385 ( Candolle 1836). — Typus: Madagascar • Alaotra-Mangoro Region [Prov. Toamasina], “province Bé tani-mena, forêts de Bé-fouroun”; 1835; W. Bojer 3; holotype: G-DC[G00453951] !

Microglossa mikanioides Baker , Journal of the Linnean Society. Botany 20: 182 ( Baker 1883). — Typus: Madagascar • Central Madagascar ; s.l.; s.d.; R. Baron 1496; lectotype ( designated here): K[K000273806] image !

Psiadia tortuosa Klatt, Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 12 (Beibl. 27): 23 ( Klatt

1890). — Typus: Madagascar • Vakinankaratra Region [Prov.

Antananarivo], “Nord-Betsiléo, Sirabé”; VIII.1880; J.M. Hildebrandt 3537; holotype: GH[GH00303964] image!; isotypes:

BM[BM000903880] image!, G[G00018143, G00018144]!,

JE[JE00019268, JE00019269] images!, M[M0147048] image!,

P[P00435708, P00435709] images!, W[W1889-0074243]

image! ICONOGRAPHY. — Drake del Castillo (1903: pl. 488); Humbert (1960: 299, fig. LIX: 13-25). DISTRIBUTION. — Madagascar (widespread except for the West) and Comoros ( Grande Comore). The species is here recorded for the first time in Comoros based on the specimen Bojer s.n. (G01094005) and confirmed by recent field observations (Y. Ibrahim, pers. comm.). This represents the third species of the genus for the country.

NOTES

Humbert (1960) treated Microglossa sessilifolia as a heterotypic synonym of Psiadia lucida . The type of the former name, kept at G-DC, has small capitula, with external bracts shorter than inner ones. In contrast, the type of Psiadia lucida shows remarkably larger capitula with external involucral bracts almost as long as the inner ones. The French botanist considered the latter as an atypical form with large capitula and suggested that it might be the result of a teratology (see isotype P02475737). He also pointed out the existence of intermediate forms such as Scott Elliot 2621 (P02475730) and Baron 4362 (P02475713: “forme à gros capitules, faisant passage vers la forme à capitules encore plus gros et à bractées élargies appelée Glycideras lucida par Cass. [ form with large capitula, leading to the form with even larger capitula and enlarged involucral bracts called Glycideras lucida by Cass.]”). Scott Elliot 2621 originating from Fort-Dauphin has involucres slightly smaller than those of the type of P. lucida but very similar in their overall shape, whereas the capitula of Baron 4362 from Central Madagascar perfectly match the typical form with smaller capitula. Humbert (1923) also indicated that both the typical form and that with large capitula might be found in the same individual as in Viguier & Humbert 973 (P02475681, P04308799). These specimens show the typical small capitula and one or two abnormal capitula that are actually galls, rather than a plant developing two types of capitula. One specimen that really possesses large capitula was identified by Humbert himself as “ Psiadia madagascariensis forma macrocephala ” (P02475635) but the name was never published. All the specimens with large capitula come from the vicinity of Fort-Dauphin in southeastern Madagascar, whereas the typical form is distributed through the eastern part of the Island from North to South, including a few localities nearby Fort-Dauphin. Since the two forms lack a differentiated geographic distribution and intermediate forms exist, we follow Humbert’s treatment and do not recognize them as distinct. Future phylogenetic data may shed more light on this taxonomic decision.