Meriania

Fernandez-Hilario, Robin, Goldenberg, Renato & Michelangeli, Fabián A., 2023, A synopsis of Meriania (Melastomataceae: Merianieae) in Peru, Phytotaxa 602 (1), pp. 1-101 : 12-13

Key to the species of Meriania in Peru

1. Leaf blades with dentate-undulate, revolute auricles at the base ( Fig. 4L), and punctiform abaxial surfaces ( Fig. 4B) M. cuzcoana

- Leaf blades without auricles (but M. rigida and M. zunacensis with revolute bases, and M. franciscana and M. neillii with slightly revolute bases), and abaxial surface not punctiform ..........................................................................................................................2

2. Inflorescences solitary, dichasia 3 or 9-flowered (often reduced to 5-flowered) ...............................................................................3

- Inflorescences in panicles with more than 10 flowers (but see comments below M. hirsuta )...........................................................5

3. Calyx calyptrate with irregular dehiscence ................................................................................................................... M. sessilifolia

- Calyx lobed with regular dehiscence..................................................................................................................................................4

4. Terminal branches and leaf blades glabrous; leaf blades 7.7–10 cm long; hypanthium terete; calyx with acute dorsal projections .. .......................................................................................................................................................................................... M. speciosa

- Terminal branches and abaxial leaf blades moderately to densely furfuraceous; leaf blades 2.3–8.2 cm long; hypanthium slightly costate; calyx with acicular dorsal projections ( Fig. 5H) .............................................................................................. M. prunifolia

5. Leaf blades bullate ( Fig. 4A); corolla campanulate and deep red; stamen connectives with dorsal-basal appendages almost perpendicular to thecae ( Fig. 6G).......................................................................................................................................................6

- Leaf blades flat to bullate; corolla spreading or campanulate, white, pink, pink-orange to reddish-orange, or fuchsia to reddish-purple but never deep red (except red in M. rubriflora ); stamen connectives with dorsal-basal appendages not perpendicular to thecae..................................................................................................................................................................................................9

6. Nodes with developed interpetiolar flaps...........................................................................................................................................7

- Nodes with only interpetiolar lines, not flaps.....................................................................................................................................8

7. Internodes quadrangular and 4-winged ( Fig. 3D); petioles with abaxial tuberculate projections (rarely horn-shaped) on the transition zone from the petiole to the midvein ( Fig. 3H) .............................................................................................................. M. tetragona

- Internodes terete-quadrangular; petioles with abaxial liguliform projections on the transition zone from the petiole to the midvein ( Fig. 3G) ........................................................................................................................................................................ M. sanguinea

8. Branches, petioles, and both leaf surfaces hirsute ( Fig. 4J); antesepalous stamen connectives with dorso-basal appendages laterally expanded............................................................................................................................................................................. M. hirsuta

- Branches, petioles, and abaxial leaf surfaces moderately to densely setulose ( Fig. 4H); stamen connectives from both cycles with dorso-basal appendages not laterally expanded .................................................................................................................. M. radula

9. Antepetalous stamens with inflated (bulbous) connectives ( Fig. 6H)..............................................................................................10

- Stamens from both cycles without inflated (bulbous) connectives ..................................................................................................13

10. Leaf blades subpeltate to peltate ( Fig. 4K), and more than 8.4 cm wide .........................................................................................11

- Leaf blades neither subpeltate nor peltate, less than 8.1 cm wide....................................................................................................12

11. Leaf blades 22.8–28.7 × 13.3–16.7 cm, peltate, abaxial surfaces pubescent to setulose .................................................... M. peltata

- Leaf blades 17.2–27.7 × 8.1–15.5 cm, subpeltate, abaxial surfaces puberulent ...................................................... M. ninakurorum

12. Leaf abaxial surface densely pubescent, the trichomes evenly covering the entire surface ( Fig. 4F); petals fuchsia to light fuchsia; antepetalous stamen connectives without dorsal appendages ................................................................................... M. bicentenaria

- Leaf abaxial surface sparsely to densely puberulent, the trichomes not covering the entire surface; petals reddish-purple; antepetalous stamen connectives with blunt ascending dorsal appendages ..................................................................................... M. franciscana

13. Stamens strongly dimorphic (connectives with different shapes, sizes and colors), antepetalous stamen connectives with apically trilobed ( Fig. 6F) or sagittate ascending dorsal appendages ............................................................................................................14

- Stamens dimorphic (connectives with different shapes and sizes but with similar colors) or isomorphic, stamen connectives from both cycles without dorsal appendages ( Fig. 6A), with dentiform dorsal appendages ( Fig. 6E), with blunt ascending dorsal appendages ( Fig. 6B) or dorsal appendages as mere humps ( Fig. 6C and 6D)................................................................................15

14. Petioles with adaxial and lateral liguliform projections on the apex; corolla white; antepetalous stamen connectives with apically trilobed ascending dorsal appendages ( Fig. 6F) ............................................................................................................ M. microflora

- Petioles without projections; corolla fuchsia; antepetalous stamen connectives with apically sagittate ascending dorsal appendages ...................................................................................................................................................................... M. urceolata

15. Corolla campanulate, pink-orange to reddish-orange (except fuchsia in M. vasquezii and red in M. rubriflora ) ( Fig. 3J).............16

- Corolla spreading, fuchsia to reddish-purple ( Fig. 3I) .....................................................................................................................22

16. Calyx calyptrate or subcalyptrate, with irregular dehiscence ( Fig. 5F) ...........................................................................................17

- Calyx neither calyptrate nor subcalyptrate, with regular dehiscence ...............................................................................................20

17. Calyx calyptrate, without dorsal projections....................................................................................................................................18

- Calyx subcalyptrate, with dorsal projections 0.5–3 mm long ( Fig. 5F) ...........................................................................................19

18. Inflorescences with flowers in regular dichasia (3-flowered) in the branchlet ends; petals 20–24 mm long ............... M. tomentosa

- Inflorescences with flowers in 5–6-flowered umbels in the branchlet ends; petals 9–10 mm long...................................... M. acida

19. Leaf blades 10.8–12.7 × 2.7–3 cm, abaxial surface sparsely to moderately puberulent, trichomes not covering the entire surface... ............................................................................................................................................................................................. M. juanjil

- Leaf blades 16.5–23.5 × 9.3–10.7 cm, abaxial surface densely villose, evenly covering the entire surface .................. M. vasquezii

20. Nodes with robust interpetiolar flaps; inflorescences pendulous; calyces with obsolete dorsal projections ................. M. rubriflora

- Nodes without interpetiolar flaps; inflorescences erect; calyces with claw-shaped dorsal projections ( Fig. 5D) ...........................21

21. Abaxial leaf surface tomentose with whitish to cream trichomes when dry; petals 19.5–24 mm long ................................ M. dazae

- Abaxial leaf surface pubescent with ferrugineous trichomes when dry; petals 13–15.5 mm long.............................. M. bongarana

22. Calyx calyptrate, with circumscissile dehiscence ( Fig. 5G)....................................................................................... M. escalerensis

- Calyx not calyptrate, with regular dehiscence..................................................................................................................................23

23. Stamens dimorphic; antesepalous stamen connectives with descending dorso-basal appendages laterally expanded ( Fig. 6I) .....24

- Stamens isomorphic; stamen connectives from both cycles with descending dorso-basal appendages not laterally expanded......28

24. Leaves subsessile (petioles up to 3 mm long), base auriculate .............................................................................. M. amischophylla

- Leaves with petioles longer than 8 mm, base acute, attenuate, or obtuse (rarely broadly obtuse in M. weberbaueri )....................25

25. Stamen connectives without dorsal appendages......................................................................................................... M. weberbaueri

- Stamen connectives with blunt ascending dorsal appendages ( Fig. 6B)..........................................................................................26

26. Hypanthium 10-costate, with longitudinal ridges up to 2.5 mm high ( Fig. 5I)............................................................... M. sumatika

- Hypanthium terete, without ridges ...................................................................................................................................................27

27. Inflorescences, hypanthia, and calyces densely tomentose, the trichomes up to 1.5 mm long......................................... M. vargasii

- Inflorescences, hypanthia, and calyces sparsely to densely furfuraceous, the trichomes up to 0.25 mm long ( Fig. 4D) .................... ............................................................................................................................................................................... M. vilcabambensis

28. Nodes with robust interpetiolar flaps (sometimes small in M. callosa ) ( Fig. 3B) ...........................................................................29

- Nodes without interpetiolar flaps .....................................................................................................................................................31

29. Internodes quadrangular and 4-winged; stamen connectives with blunt ascending dorsal appendages ( Fig. 6B) ..... M. megaphylla

- Internodes quadrangular, but not winged; stamen connectives with dorsal appendages as mere humps or obsolete......................30

30. Petioles 25–50 mm long, with an adaxial projection (scutum) on the transition zone from the petiole to the midvein ( Fig. 3E)....... ...................................................................................................................................................................................... M. zunacensis

- Petioles 10–22 mm long, without projections ..................................................................................................................... M. callosa

31. Petioles with an apical adaxial projection ( Fig. 3F); petals abaxially moderately to densely puberulent ........................... M. drakei

- Petioles without projections; petals glabrous ...................................................................................................................................32

32. Leaf blades with entire margins, and the adaxial surfaces flat.........................................................................................................33

- Leaf blades with denticulate margins, and the adaxial surfaces flat to bullate ................................................................................34

33. Flowers 6-merous; calyx without dorsal projections ( Fig. 5A)............................................................................................. M. neillii

- Flowers 5-merous; calyx with thick, callose dorsal projections........................................................................................... M. rigida

34. Leaf venation with 1 pair of secondary veins (lateral nerves) and an additional pair of faint submarginal veins.............. M. rugosa

- Leaf venation with 2 pairs of secondary veins (lateral nerves) and an additional pair of faint submarginal veins .........................35

35. Internodes quadrangular and 4-winged, wings 1–3.5 mm high ( Fig. 3C); calyx with callose dorsal projections, whitish and much lighter than the rest of the calyx and hypanthium when dry ( Fig. 5C)...................................................................... M. penningtonii

- Internodes quadrangular, without wings; calyx with small conic dorsal projections, of the same color as the rest of the calyx and hypanthium when dry ................................................................................................................................................... M. tetraquetra