Psiadia salicifolia J. Calvo & Callm., 2025

4. Psiadia salicifolia J. Calvo & Callm. , sp. nov. ( Figs 4; 5)

DIAGNOSIS. — Among the disciform species of the genus, Psiadia salicifolia is unique for its linear leaves whitish-lanate on the abaxial surface. TYPUS. — Madagascar • Alaotra-Mangoro Region [Prov. Toamasina], Ambatondrazaka, Réserve de Zahamena , lit de la riv. Manambato ; 17°30’49”S, 48°45’13”E; 950 m alt.; 23.VII.1997; S. Wohlhauser, M. O. Laivao & M. W. Callmander s.n.; holotype: G[G00618075]!; isotypes: MO!, P GoogleMaps !

PHENOLOGY. — Collected in flower in June and July.

DISTRIBUTION AND ECOLOGY. — Endemic to Madagascar, known from the central-eastern medium altitude moist evergreen forests (sensu Gautier et al. 2018). This species grows on rocky riverbeds.

ETYMOLOGY. — The epithet salicifolia has been chosen because of the resemblance of the leaves of the new species to some species of the genus Salix L., e.g., S. eleagnos Scop.

CONSERVATION STATUS. — Psiadia salicifolia sp. nov., is known from two locations encompassed within the Corridor Ankeniheny-Zahamena and Zahamena protected areas. The new species has an extent of occurrence (EOO) and an area of occupancy (AOO) of 8 km ². Deforestation due to fires for slash-and-burn agriculture is considerable in the extreme south of the Corridor Ankeniheny Zahamena where one of the two known locations occurs ( Goodman et al. 2018). Due to these plausible threats, P. salicifolia , sp. nov., is assigned to a preliminary risk of extinction status of “Endangered” [EN B1ab(ii, iii, iv, v) + 2ab(ii, iii, iv, v)] using the IUCN Red List Categories and Criteria ( IUCN 2012).

ADDITIONAL SPECIMENS EXAMINED. — Madagascar • Atsinanana Region [Prov. Toamasina], Vatomandry, Ambalabe , Sahanionaka , forêt de Vohibe, au bord de la riv. Talaviana , de Tsitondroina vers l'ouest; 19°10’44”S, 48°32’29”E; 728 m alt.; 1.VI.2010; A. Razanatsima 848; MO[MO-3028060] image!, P[P00982567]!, TAN image GoogleMaps !

DESCRIPTION

Subshrubs 0.3 m high, stems leafy on upper part, lower parts naked with conspicuous leaf-scars. Leaves alternate, simple, sessile, densely arranged; laminas 35-55 × 2-3.6 mm, linear to slightly broadened in distal third, base attenuate, apex rather acute, margins entire except for distal third somewhat crenulate, glabrescent on adaxial surface, whitish-lanate on abaxial surface, venation pinnate with secondary veins conspicuous, not covered by indumentum. Synflorescences terminal, corymbiform, composed of usually 10-15 capitula; bracts linear to subulate, decreasing in size from base to capitula, basal ones similar to upper leaves but smaller. Capitula on pedicels 7-32 mm long, with remnants of arachnoid trichomes; receptacle flat to slightly convex, epaleate, fimbrillate. Involucres 4-5 × 5-7 mm (in dried specimens), hemispherical, glabrous, straw-colored; involucral bracts 31-33, 3-4-seriate, imbricate, subequal, outer ones linear-subulate, 2.9-3.1 × 0.5-0.6 mm, acute, entire, middle ones linear-oblong, 3.8-4.1 × 0.9-1 mm, acuminate, scarious marginally, inner ones as middle ones but narrower. Peripheral florets c. 23, 1-seriate, pistillate, tubulose; corolla 2.4-2.8 mm long, with trichomes in middle part, irregularly 3-5-lobed (lobes somewhat atrophied), whitish to pale yellow; style c. 3.6 mm long, branches c. 1 mm long, not broadened apically, rather smooth, pale yellow. Disc florets c. 19, functionally staminate, tubulose; corolla 2.9-3.2 mm long, with trichomes in middle part, lobes c. 0.8 × 0.35 mm, whitish to pale yellow; stamens with filament collars cylindrical, anthers c. 1.13 mm long (including appendages), apical appendages c. 0.27 × 0.13 mm, oblong, anther bases obtuse to shortly auriculate; style c. 4.2 mm long, branches 0.8 mm long, broadened apically, papillose, pale yellow. Achenes of peripheral florets 2-2.1 × 0.56-0.65 mm, subprismatic, 5-ribbed, glabrous except for some papillae at apex; pappus 1-seriate, 2.6-3 mm long, barbellate, white; achenes of disc florets sterile; pappus as in peripheral florets.

NOTES

Psiadia salicifolia is related to the species group comprising erect shrubs or subshrubs with tubulose peripheral florets, glabrescent adaxial leaf surfaces, tomentose adaxial leaf surfaces, and non-attenuate leaf apices. This group includes P. alticola Humbert , P. coursii Humbert , P. leucophylla Humbert , P. marojejyensis (Humbert) Humbert , and P. tsaratananensis Humbert. From these taxa the new species clearly differs by its linear leaves and, as far we know, it does not co-occur with any of them. Any confusion is therefore unlikely.