Meriania Sw.

Fernandez-Hilario, Robin, Goldenberg, Renato & Michelangeli, Fabián A., 2023, A synopsis of Meriania (Melastomataceae: Merianieae) in Peru, Phytotaxa 602 (1), pp. 1-101 : 7-8

Meriania Sw. , nom. cons., Fl. Ind. Occ. 2: 823, t. 15. 1798. ( Figures 3–7 ).

Type species: Rhexia leucantha Sw. , type cons. [= Meriania leucantha (Sw.) Sw. ].

Trees or shrubs, rarely climbers, distal branchlets glabrous or with various indument types. Young branches terete, quadrangular, or 4-winged; nodes with interpetiolar lines, flaps or without modifications. Leaves opposite, isophyllous to slightly anisophyllous. Petioles with projections or without modifications. Leaf blades petiolate or sessile, sometimes subpeltate or peltate; venation acrodromous basal or suprabasal; glabrous or covered with various indument types. Inflorescences terminal or pseudo-lateral (initially terminal but overtopped by the developing axillary bud) panicles, rarely dichasia, or solitary flowers. Flowers (4–)5–6-merous; diplostemonous; with spreading to campanulate corollas. Hypanthium terete to costate; glabrous or covered with various indument types. Calyx lobed, repand, truncate, subcalyptrate or calyptrate; dehiscence regular, irregular or circumscissile; with dorsal projections, acicular, claw-shaped, conic, callose, blunt or obsolete; glabrous or covered with various indument types. Petals oblong, obovate, slightly obovate, or strongly asymmetrically obovate; glabrous, rarely puberulent or slightly ciliate. Stamens isomorphic to strongly dimorphic, all bent to one side of the flower at anthesis giving the flower a zygomorphic appearance; filaments flat to semiterete; connectives sometimes prolonged below the thecae or abruptly inflated (bulbous), with two appendages, one dorso-basal and the other dorsal, the former descending or almost perpendicular to the thecae, sometimes laterally expanded, the latter obsolete to ascending; anthers usually opening by one dorsally inclined pore, thecae with smooth to corrugated surfaces. Ovary superior, sometimes ½ inferior, usually glabrous; style incurved at the apex and opposite to the anthers at anthesis, glabrous. Fruits capsular (velatidia), with persistent hypanthium, calyx persistent or caducous; mature ovary exceeding the hypanthium length or completely concealed by the hypanthium. Seeds triangular-linear, numerous.

Distribution and habitat:— Peru presents 36 species of Meriania , of which 25 are endemic. Twenty-four species were found in northern Peru within the Amotape-Huancabamba Zone (see Weigend 2002, Tejedor & Calatayud 2022) (Table 1), which holds the highest species richness in Peru. The departments with the highest number of species are Amazonas (18 species), Cajamarca (11 species) and San Martín (9 species) ( Figure 7 ). Most species have restricted distributions, and only four species ( M. neilli , M. radula , M. sanguinea and M. tomentosa ) occur in more than five departments. The Peruvian species of Meriania grow mainly in the eastern flanks of the Andes in premontane forests, montane forests, elfin forests and subparamos at 350–3500 m, but two species ( M. escalerensis and M. microflora ) grow in the sub-Andean cordilleras (Andean Tepuis sensu Neill et al. 2014).

Figures

FIGURE 3. Morphological characteristics of Peruvian Meriania. A. Interpetiolar line (M. tomentosa; R. W. Bussmann et al. 17068). B. Interpetiolar flap (M. zunacensis; R. Fernandez-Hilario et al. 1920). C. Winged internode (M. penningtonii; R. Fernandez-Hilario et al. 2072). D. Winged internode (M. tetragona; R. Fernandez-Hilario et al. 2092). E. Adaxial projection (scutum) in the transition zone from the petiole to the midvein (M. zunacensis; R. Fernandez-Hilario et al. 1920). F. Swollen adaxial projection on the petiole apex (M. drakei; R. Fernandez-Hilario et al. 1775). G. Liguliform abaxial projections in the transition zone from the petiole to the midvein (M. sanguinea; R. Fernandez-Hilario et al. 1896). H. Tuberculate abaxial projections in the transition zone from the petiole to the midvein (M. tetragona; F. A. Michelangeli et al. 1739). I. Spreading corolla (M. rigida; R. Fernandez-Hilario et al. 1931). J. Campanulate corollas (M. dazae; J. L. Marcelo-Peña et al. 6568). K. Fruits with mature ovaries exceeding the hypanthia length (M. sanguinea; F.A. Michelangeli et al. 2743). L. Fruits with mature ovaries completely concealed by the hypanthia (M. tomentosa; F. A. Michelangeli et al. 1799). Photos by Rainer W. Bussmann (A); Robin Fernandez-Hilario (B–G and I–J); and Fabián A. Michelangeli (H, K and L).

FIGURE 4. Morphological characteristics of Peruvian Meriania. A. Bullate adaxial leaf surface (M. sanguinea; R. Fernandez-Hilario et al. 1896). B. Punctiform abaxial leaf surface (M. cuzcoana; W. Farfán et al. 976). C. Glabrous abaxial leaf surface (M. callosa; R. Fernandez-Hilario et al. 2055). D. Furfuraceous abaxial leaf surface (M. vilcabambensis; L. Valenzuela 7494). E. Puberulent abaxial leaf surface (M. drakei; R. Fernandez-Hilario et al. 1775). F. Pubescent abaxial leaf surface (M. bicentenaria; A. Monteagudo et al. 6960). G. Tomentose abaxial leaf surface (M. tomentosa; R. Fernandez-Hilario et al. 1905). H. Setulose abaxial leaf surface (M. radula; D. Paredes et al. 604). I. Villose abaxial leaf surface (M. sumatika; I. Huamantupa et al. 2060). J. Hirsute adaxial leaf surface (M. hirsuta; S. Baldeón & J. Campos 5373). K. Peltate leaf base (M. peltata; R. Fernandez-Hilario et al. 2093). L. Leaf base with dentate-undulate revolute auricles (M. cuzcoana; L. Valenzuela et al. 6904).

FIGURE 5. Morphological characteristics of Peruvian Meriania. A. Calyx lacking dorsal projections (M. hexamera; I. Revilla 3484). B. Calyx with callose dorsal projections (left), and detail of a dorsal projection (right) (M. callosa; R. Fernandez-Hilario et al. 2055). C. Calyx with whitish callose dorsal projections (M. penningtonii; R. Fernandez-Hilario et al. 2072). D. Calyx with claw-shaped dorsal projections (M. dazae; J. L. Marcelo-Peña et al. 6568). E. Calyx with blunt dorsal projections (M. rugosa; H. van der Werff 17006). F. Subcalyptrate calyx with small claw-shaped projections and irregular dehiscence (left), and detail of the subcalyptrate calyx apex (right) (M. vasquezii; R. Vásquez et al. 45480). G. Calyptrate calyx with circumscissile dehiscence (M. escalerensis; M. Ríos et al. 3316). H. Calyx with aciculate dorsal projections and slightly costate hypanthium (M. prunifolia; J. Schunke-Vigo 11712). I. Costate hypanthium with 10 evident ribs (left) and apical view (right) (M. sumatika; P. Núñez & J. Arque 8369).

FIGURE 6. Morphological characteristics of Peruvian Meriania. A. Stamen with a triangular descending dorso-basal appendage (black arrow) but no dorsal appendage (M. tetraquetra; R. Fernandez-Hilario & A. Vásquez 251). B. Stamen with a triangular descending dorso-basal appendage and a blunt ascending dorsal appendage (blue arrow) (M. megaphylla; A. Weberbauer 7048). C. Stamen with an acuminate descending dorso-basal appendage (black arrow) and a dorsal appendage as a mere hump (blue arrow) (M. franciscana; C. Díaz & S. Fernández 10150). D. Stamen with a triangular descending dorso-basal appendage and a dorsal appendage as a mere hump, and detail of the dorsal appendage (M. rugosa; F. A. Michelangeli et al. 1725). E. Stamen with a triangular descending dorso-basal appendage and a dentiform dorsal appendage, and detail of the dorsal appendage (M. hexamera; I. Revilla 3484). F. Stamen with a multilobed descending dorso-basal appendage and an apically trilobed ascending dorsal appendage, and detail of the dorsal appendage apex (M. microflora; I. Huamantupa et al. 15552). G. Stamen with an almost perpendicular dorso-basal appendage to the theca, and detail of the prolonged connective below the theca (M. tetragona; R. Fernandez-Hilario et al. 2092). H. Stamen with inflated (bulbous) connective (blue arrow) (M. bicentenaria; R. Villanueva-Espinoza 675). I. Antesepalous stamen with a laterally expanded dorso-basal appendage (left) and antepetalous stamen with a dorso-basal appendage not laterally expanded (right) (M. vilcabambensis; L. Valenzuela 7494).

FIGURE 7. Map with the locations of the examined Meriania specimens in this treatment (left), and map with species richness showing the most diverse grids in red (right). Departmental abbreviations: AM (Amazonas), AN (Ancash), AP (Apurímac), AR (Arequipa), AY (Ayacucho), CA (Cajamarca), CU (Cusco), HU (Huánuco), HV (Huancavelica), IC (Ica), JU (Junín), LA (Lambayeque), LI (Lima), LL (La Libertad), LO (Loreto), MD (Madre de Dios), MO (Moquegua), PA (Pasco), PI (Piura), PU (Puno), SM (San Martín), TA (Tacna), TU (Tumbes) and UC (Ucayali).