Myrtaceae

Amorim, Gabriela Dos Santos, Barbosa, Maria Regina De Vasconcellos, Jr, Eduardo Bezerra De Almeida & Thomas, William Wayt, 2022, Taxonomic study of Myrtaceae in forest fragments in Amazonian Maranhão, Brazil, Phytotaxa 568 (1), pp. 27-60 : 29-31

Myrtaceae

Trees or shrubs, twigs glabrescent or densely pubescent, grayish or reddish. Leaves simple and opposite, margin entire, venation brochidodromous, stipules absent, glands present. Inflorescence axillary, terminal or subterminal, a solitary flower, panicles, thyrsoid, simple or auxotelic racemes, fascicles, glomerules, dichasium, cauliflorous; flowers radially symmetric, bisexual, dichlamydeous, sessile or pedicellate; bracts and bracteoles caducous or persistent; flowers bud constricted or not below ovary; calyx 4–5–merous, the lobes free, partially fused in the lower third of the bud or completely fused and opening by tearing or along the suture of a calyptra; corolla 4–5–merous, often ephemeral; stamens numerous. Fruit subglobose, globose, or ellipsoid, seeds few to numerous.

Key to the species to Myrtaceae in forest fragments in Amazonian Maranhão

1. Inflorescence a panicle or thyrsoid.....................................................................................................................................................2

- Inflorescence a solitary flower, glomerule, fascicle, dichasium, or a simple or auxotelic raceme ..................................................17

2. Calyx-lobes free or partially fused in the lower third of the bud and 5-merous ................................................................................3

- Calyx-lobes completely fused, opening by tearing or as a calyptra .................................................................................................14

3. Flower buds constricted above ovary and calyx reflexed ..................................................................................................................4

- Flower buds not constricted above and calyx not reflexed ................................................................................................................5

4. Leaves with petioles unchanneled, leaf discolorous and flowers sessile ................................................................ Myrcia tomentosa

- Leaves with petioles channeled, leaf concolorous and flowers pedicellate, 2.5–3.5 mm long....................................... Myrcia selloi

5. Midvein adaxially prominent; ovary 3-locular....................................................................................................... Myrcia guianensis

- Midvein adaxially flat, impressed or sulcate; ovary 2-locular ...........................................................................................................6

6. Leaf apex long-caudate; lateral veins prominent abaxially, arched....................................................................... Myrcia minutiflora

- Leaf apex acute, acuminate, long acuminate, attenuate, rounded or obtuse, rarely cuspidate; lateral veins not prominent abaxially and not arched.....................................................................................................................................................................................7

7. Inflorescence a thyrsoid with congested flowers; aggregated in dichasia, the first branch ca. 1.5 cm above the base; bracteoles 7–8 × 3 mm ...................................................................................................................................................................... Myrcia bracteata

- Inflorescence a panicle with lax flowers, the first branch more than 1.5 cm above the base; bracteoles more or less 0.5–1.5 × 2 mm ......................................................................................................................................................................................................8

8. Margin revolute; lateral veins strongly marked............................................................................................................. Myrcia eximia

- Margin flat; lateral veins not marked .................................................................................................................................................9

9. Leaf pubescent abaxially; fruits pubescent.......................................................................................................................................10

- Leaf glabrous or glabrescent abaxially; fruits glabrous ...................................................................................................................12

10. Flower bud campanulate; fruit globose ........................................................................................................................ Myrcia cuprea

- Flower bud globose; fruit oblong or ellipsoid ..................................................................................................................................11

11. Leaf with petioles unchanneled and blades slightly discolorous, lustrous adaxially; midvein adaxially sulcate ..... Myrcia sylvatica

- Leaf with channeled petiole and blades concolorous; midvein adaxially flat......................................................... Myrcia splendens

12. Leaf membranaceous, concolorous ......................................................................................................................... Myrcia multiflora

- Leaf chartaceous or coriaceous, discolorous....................................................................................................................................13

13. Branches reddish; panicle with the axis glabrous................................................................................................... Myrcia amazonica

- Branches grayish; panicle with the axis pubescent, the indumentum whitish ............................................................ Myrcia grandis

14. Leaf membranaceous; panicle with axis 0.5-0.7 mm ............................................................................................. Myrcia fasciculata

- Leaves chartaceous or coriaceous; panicle with the axis more than 2.3 cm long ............................................................................15

15. Twigs pubescent, with indumentum ochraceous; intramarginal vein 1-3 mm from the margin ....................... Myrcia neoclusiifolia

- Twigs glabrous; intramarginal vein 1 mm or less from the margin..................................................................................................16

16. Leaf with margin revolute; panicle and fruit pubescent....................................................................................... Myrcia neospeciosa

- Leaf with margin flat; panicle and fruit glabrous........................................................................................................... Myrcia pullei

17. Calyx 4-merous; ovary 2-3-locular ..................................................................................................................................................18

- Calyx 4-5-merous; ovary plurilocular ..............................................................................................................................................34

18. Pedicels more than 1 mm long; calyx-lobes persistent in the fruit...................................................................................................19

- Pedicels absent; calyx-lobes caducous in the fruit together with the petals and hypanthium as a unit............................................33

19. Flowers arranged in fascicles, sometimes only two flowers per axis...............................................................................................20

- Flowers arranged in racemes............................................................................................................................................................26

20. Leaves membranaceous...................................................................................................................................... Eugenia lambertiana

- Leaves chartaceous or coriaceous ....................................................................................................................................................21

21. Inflorescence cauliflorous ..................................................................................................................................... Eugenia flavescens

- Inflorescence axillary .......................................................................................................................................................................22

22. Calyx lobes deltate, pubescent adaxially and glabrous abaxially............................................................. Eugenia wullschlaegeliana

- Calyx lobes obovate, orbicular or oblong, glabrous or sparsely pubescent .....................................................................................23

23. Midvein adaxially sulcate......................................................................................................................................... Eugenia protenta

- Midvein adaxially impressed, prominent or flat...............................................................................................................................24

24. Leaf discolorous; the margin revolute.................................................................................................................. Eugenia dittocrepis

- Leaf concolorous; the margin flat.....................................................................................................................................................25

25. Twigs pubescent; bracts lanceolate and bracteoles orbicular ............................................................................... Eugenia punicifolia

- Twigs glabrous; bracts orbicular and bracteoles elliptic or oblong..................................................................... Eugenia stictopetala

26. Raceme auxotelic with cataphylls at the base ............................................................................................................ Eugenia patrisii

- Raceme simple..................................................................................................................................................................................27

27. Lateral veins arched; inflorescence glabrescent ......................................................................................................... Eugenia florida

- Lateral veins not arched; inflorescence pubescent ...........................................................................................................................28

28. Twigs glabrous; bracts caducous before anthesis .............................................................................................................................29

- Twigs densely or sparsely pubescent; bracts caducous after anthesis ..............................................................................................30

29. Intra-marginal vein 4–6 mm from the margin; midvein sulcate; fruit oblong to ellipsoid.......................... Eugenia caducibracteata

- Intra-marginal vein 1–3 mm or less from the margin; midvein flat; fruit globose.................................................. Eugenia cupulata

30. Calyx-lobes partially fused in the lower third of the bud; fruit glabrous ...................................................... Eugenia densiracemosa

- Calyx-lobes free; fruit pubescent......................................................................................................................................................31

31. Leaves concolorous; leaf margin revolute.................................................................................................................. Eugenia biflora

- Leaves discolorous; leaf margin flat.................................................................................................................................................32

32. Bracts caducous after anthesis; fruit with muricate surface ....................................................................................... Eugenia patens

- Bracts persisting in the fruit; fruit with smooth surface ..................................................................................... Eugenia polystachya

33. Leaves 4.4–7.3 × 2.8–3 cm, apex leaf acuminate............................................................................................... Myrciaria floribunda

- Leaves 1–2.5 × 0.5–1.2 cm, apex leaf acute............................................................................................................. Myrciaria tenella

34. Intra-marginal vein 1–2 mm from the margin; bracts and bracteoles persistent in the fruit .......................... Calycolpus goetheanus

- Intra-marginal vein absent; bracts and bracteoles caducous after anthesis ......................................................................................35

35. Calyx-lobes partially fused in the lower third of the bud; fruit with smooth surface ............................... Campomanesia aromatica

- Calyx-lobes completely fused, opening by irregular tearing; fruit with surface marked with glands .............................................36

36. Leaf apex always apiculate; midvein adaxially sulcate; flower buds globose .................................................. Psidium acutangulum

- Leaf apex never apiculate; midvein adaxially impressed; flower buds pyriform .................................................. Psidium guineense