Genus Acalypha L.

Species Plantarum: 1003 (Linnaeus 1753); Genera Plantarum, ed. 5: 436 (Linnaeus 1754). — Type: Acalypha virginica L . (lectotype designated bySmall 1913: 457). — An Illustrated Flora of the Northern United States, ed. 2., 2: 457.

Mercuriastrum Heist. ex Fabr., Enumeratio Methodica Plantarum: 202 (Fabricius 1759). — Type: not designated.

Cupameni Adans., Familles des Plantes (Adanson), 2: 356 (Adanson 1763), nom. illeg. et superfl. — Type: not designated.

Caturus L., Mantissa Plantarum. Generum Editionis vi et Specierum Editionis II: 19 (Linnaeus 1767). — Galurus Spreng., Anleitung zur Kenntniss der Gewachse, Zweite 364 (Sprengel 1817) nom. illeg. — Type: Caturus spiciflora L. [syn. of Acalypha hispida Burm.f.].

Usteria Dennst., Schlüssel Hortus Malabaricus: 31 (Dennstaedt 1818); non Usteria Willd., nec Usteria Medikus, nec Usteria Cav. — Type: not designated.

Cupamenis Raf., Sylva Telluriana. Mantis Synopt. New genera and species of trees and shrubs of North America: 67 (Rafinesque 1838), non Cupameni Adans. — Type: Acalypha indica L.

Acalyphes Hassk., Catalogus Plantarum in Horto Botanico Bogoriensi Cultarum Alter. Bataviae: 235 (Hasskarl 1844), orth. var.

Linostachys Klotzsch ex Schltdl., Linnaea 19: 235 (Schlechtendal 1847). — Type: Linostachys padifolia Schltdl. [syn. of Acalypha schlechtendaliana Müll.Arg.]

Odonteilema Turcz., Bulletin de la Société impériale des Naturalistes de Moscou 21: 587 (Turchaninov 1848). — Type: Odonteilema claus - seni Turcz. [syn. of Acalypha clausseni (Turcz.) Baill.].

Paracelsea Zoll., Natuurkundig Tijdschrift voor Nederlandsch-Indië, 14 (4): 171 (Zollinger 1857), nom. illeg.

Calyptrospatha Klotzsch ex Baill., Étude générale du Groupe des Euphorbiacées: 440 (Baillon 1858). — Type: Calyptrospatha pubiflora Klotzsch [syn. of Acalypha pubiflora (Klotzsch) Baill.].

Gymnalypha Griseb., Bonplandia (Hannover) 6: 2 (Grisebach 1858).— Type: Gymnalypha jacquinii Griseb., nom. illeg. [syn. of Acalypha villosa Jacq.].

Corythea S.Watson, Proceedings of the American Academy of Arts and Sciences, Boston 22: 451 (Watson 1887). — Type: Corythea filipes S.Watson [syn. of Acalypha filipes (S.Watson) McVaugh].

Ricinocarpus Burm. ex Kuntze, Revisio Generum Plantarum 2: 615 (Kuntze 1891), nom. illeg., non Ricinocarpos Desf. — Type: Acalypha lanceolata Willd.

Schizogyne Ehrenb. ex Pax & K.Hoffm., Das Pflanzenreich (Engler), IV, 147, XVI: 178 (Pax & Hoffmann 1924), nom. illeg., non Schizogyne Cass. — Type: Schizogyne ciliata Ehrenb. [syn. of Acalypha ciliata Forssk.].

Acalyphopsis Pax & K.Hoffm., Das Pflanzenreich (Engler), IV, 147, XVI: 178 (Pax & Hoffmann 1924). — Type: Acalyphopsis celebica Pax & K.Hoffm., nom. dub. [syn. of Acalypha hoffmanniana Hurus.].

DISTRIBUTION, HABITAT, AND CLASSIFICATION. — A pantropical genus of about 500 species, with centers of diversity in Mexico and east tropical Africa, and including 49 species in WIOR (42 native and 7 probably introduced). Acalypha is distributed in all the archipelagos in the WIOR and grows in a wide variety of habitats. Following the subgeneric classification of Levin et al. (2022), subg. Androcephala Pax & K.Hoffm. is represented by one species ( A. diminuta), subg. Hypandrae (Müll.Arg.) Hurus. by one species ( A. baretiae), and subg. Acalypha by 47 species. The fourth subgenus, Linostachys (Klotzsch ex Schltdl.) Pax & K.Hoffm., does not occur in WIOR. Madagascar is the only island in WIOR where three subgenera are present; other regions of WIOR are home only to species in subg. Acalypha . The species in subg. Acalypha found in WIOR do not represent a monophyletic group (Montero Muñoz 2021; Levin et al. 2022).

DESCRIPTION

Small trees, shrubs, or rarely herbs, evergreen or deciduous, monoecious or rarely dioecious. Branches usually slender, rarely thorny or with brachyblasts. Indumentum velutinous, pubescent or sparsely hairy, rarely absent (glabrous); trichomes simple (long or short, erect, curved, or appressed, sometimes hyaline), glandular (long, short, or resinous flattened/rounded), rarely stellate. Axillary buds naked or perulate, then with two perules that are imbricate or valvate or four perules that are overlapping (superposed), chartaceous or membranous. Stipules usually caducous, linear to triangular or ovate-lanceolate. Leaves alternate, undivided, usually petiolate and stipulate. Leaf blades entire or more commonly dentate or crenate-serrate, rarely lobed; venation actinodromous or pinnate. Stipels sometimes present at apex of petiole or leaf base, minute, glandular, filiform or triangular-lanceolate. Inflorescences unisexual or bisexual, axillary, terminal or both, usually spiciform, less commonly racemose or glomerate. Male inflorescences always axillary, spiciform, densely or laxly flowered, with several flowers at each node, subtended by a minute bract. Female inflorescences usually spiciform, sometimes glomerulate, bracteate, with 1-3 flowers per node; bracts minute at anthesis, usually accrescent and foliaceous in the fruit, sometimes non-accrescent, margin entire, crenate, or dentate, sometimes with two bracteoles at base. Bisexual inflorescences usually spiciform, sometimes racemose, usually with female flowers below and male above (androgynous), rarely with male flowers below and female above (gynecandrous). Flowers unisexual, apetalous, disc absent. Male flowers inconspicuous, short-pedicellate; calyx 4-lobed, stamens 8, thecae 2, pendulous and vermiform at anthesis; pollen small, oblate-spheroidal to suboblate, apertures 3-8, brevicolporate; pistillode absent. Female flowers usually sessile or subsessile, rarely pedicellate; calyx of 3[-4] or sometimes 5 small sepals, distinct or connate at base; ovary with [2]-3 carpels, surface smooth, papillose, or echinate, usually pubescent to densely hispid, sometimes glabrous; styles [2]-3, usually reddish, distinct or connate at base, each divided in several filiform segments; stigmas smooth; ovules 1 per locule. Allomorphic female flowers sometimes present, solitary, at apex of the inflorescences or axillary; ebracteate, long-pedicellate or subsessile, calyx as in the normal female flowers, ovary 1-2[-3] lobed, distally fimbriate or papillose, styles 1-2[-3], subbasal (rarely terminal). Fruits from normal flowers capsular, [2]-3 lobed, soon dehiscing septicidally into 2-3 bivalved cocci; usually surrounded by the accrescent female bract; surface smooth, papillose, or echinate, usually pubescent to hispid, sometimes glabrous; those from allomorphic flowers indehiscent or schizocarps with indehiscent mericarps, usually distally fimbriate or sharply papillate. Seeds usually piriform, sometimes subglobose or globose, minutely foveolate or foveolate, caruncle usually very reduced.

TAXONOMIC RESULTS

We found a total of 163 names associated with Acalypha of WIOR (Appendix II) published prior to the beginning of our work, of which we accept 36 names (including three new combinations, one made in this paper), 92 are considered as synonyms (7 for the first time here), and 2 are excluded from the genus. The remaining names are invalid or excluded names. Finally, in previous works, we have described 12 new Acalypha species (Montero Muñoz et al. 2018b, 2020a, 2020 b, 2022, and another one in this paper).

KEY TO THE SPECIES OF ACALYPHA OF WESTERN INDIAN OCEAN REGION (WIOR)

1. Female flowers pedicellate, calyx with 5 sepals; female bracts not enlarging in fruit (subg. Androcephala and Hypandrae) .................................................................................................................................................. 2

— Female flowers sessile, calyx with 3[4] sepals; female bracts enlarging in fruit, except in A. crateriana comb. nov., A. hispida, and A. marginata (subg. Acalypha) .............................................................................................. 3

2. Inflorescences gynecandrous; male segment 2-3(-3.5) cm long, flowers glomerate .......................................... ..................................................................................................................... A. baretiae I.Montero & Cardiel

— Inflorescences androgynous; male segment to 0.5 cm long, flowers in a racemose to subumbelliform cluster ...... ........................................................................................................................................... A. diminuta Baill.

3. Inflorescences all unisexual .......................................................................................................................... 4

— Inflorescences mostly androgynous (sometimes with the male segment caducous), rarely male inflorescences and/or solitary axillary female bracts .......................................................................................................... 21

4. Female inflorescences sessile or subsessile, with 1 bract that enlarges in fruit, or flowers glomerate and bracts not enlarging ............................................................................................................................................... 5

— Female inflorescences pedunculate (peduncle more than 5 mm long, usually more than 10 mm long), with more than 2 bracts, usually many, rarely 1 ............................................................................................................ 9

5. Leaf blades linear, c. 0.2 cm wide .................................................................................. A. linearifolia Leandri

— Leaf blades not linear, 1-7(-8) cm wide ....................................................................................................... 6

6. Petioles (2-) 3-4.5 cm long; leaf blades membranous, with pocket-shaped domatia on the lower surface ......... ................................................................................................................... A. isaloensis I.Montero & Cardiel

— Petioles 0.5-2.5(-3) cm long; leaf blades chartaceous or coriaceous (the mature leaves), without domatia .... 7

7. Leaf blades reddish on lower surface, without discolorous margin; stipules triangular-lanceolate, with two translucent lateral wings; female inflorescences with 1 bract enlarging in fruit ........................ A. integrifolia Willd.

— Leaf blades greenish on lower surface, usually with discolorous margin; stipules linear-lanceolate, without wings; female inflorescences in glomerules of 3-4 flowers with bracts not enlarging in fruit .................................... 8

8. Leaf blades to 10 cm long, elliptic to obovate, with reddish margin ................................................................ ................................................................................. A. crateriana (Coode) I.Montero & Cardiel, comb. nov.

— Leaf blades to 21 cm long, elliptic-lanceolate, with usually pale margin .......................................................... ........................................................................................................................... A. marginata (Poir.) Spreng.

9. Female inflorescences with (1-)2-4 bracts, to 6 bracts in A. chibomboa ...................................................... 10

— Female inflorescences with more than (4-)9 bracts ..................................................................................... 13

10. Leaf blades 1.5-2.5(-4)[-7.5] cm long, elliptic to oblong, sometimes obovate ................................................. ...................................................................................................................................... A. decaryana Leandri

— Leaf blades (5-)7-12(-18)[-26.5] cm long, elliptic-lanceolate to ovate-lanceolate, sometimes obovate-lanceolate ............................................................................................................................................................ 11

11. Female bracts to 5 mm long, orbicular, denticulate ........................................... A. chibomboa Baill. (in part)

— Female bracts to 9-15 mm long, orbicular-reniform, dentate ..................................................................... 12

12. Leaf blades elliptic-lanceolate to obovate-lanceolate; base acute to cuneate ........................ A. emirnensis Baill.

— Leaf blades ovate-lanceolate; base rounded to subcordate ......................................... A. lepidopagensis Leandri

13. Female bracts with only simple trichomes ................................................................................................. 14

— Female bracts with simple and glandular trichomes or only with glandular trichomes ............................... 16

14. Female inflorescences subterminal, laxly flowered, c. 3 cm long ............ A. rabesahalana I.Montero & Cardiel

— Female inflorescences axillary, densely flowered, 10-40 cm long ................................................................ 15

15. Leaf blades not variegated; female inflorescences up to 40 cm long, pendulous; female bracts not increasing in fruit ....................................................................................................................................... A. hispida L.

— Leaf blades variegated; female inflorescences up to 10 cm long, more or less erect; female bracts increasing in fruit ...................................................................................................................... A. wilkesiana Müll.Arg.

16. Leaf blades bullate ..................................................................................................................................... 17

— Leaf blades not bullate ............................................................................................................................... 18

17. Leaf blades ovate-lanceolate; stipules to 13 mm long, elliptic to ovate-elliptic ........ A. andringitrensis Leandri

— Leaf blades narrowly triangular-lanceolate to linear-lanceolate; stipules to 8 mm long, triangular-lanceolate .............................................................................................................................................. A. radula Baker

18. Leaf blades with simple and glandular trichomes ................................................ A. rottleroides Baill. (in part)

— Leaf blades with only simple trichomes ..................................................................................................... 19

19. Leaf blades 2-6(-13) cm long; female bracts dentate ............................................. A. spachiana Baill. (in part)

— Leaf blades (3.5-) 7-17 cm long; female bracts entire ................................................................................. 20

20. Petioles (2-) 3-8 cm long; leaf blades broadly ovate-lanceolate, base rounded to cordate; female inflorescences to 8.5 cm long .................................................................................................. A. leandrii I.Montero & Cardiel

— Petioles (1-) 2-3 cm long; leaf blades ovate-lanceolate to oblong-lanceolate, base rounded to truncate; female inflorescences to 13 cm long .............................................................................................. A. vulneraria Baill.

21. Androgynous inflorescences with inconspicuous male segment (3.5-15 mm long) ..................................... 22

— Androgynous inflorescences with conspicuous male segment (20-90 mm long) ......................................... 31

22. Annual or perennial herbs [allochthonous species] .................................................................................... 23

— Shrubs [native species] ............................................................................................................................... 27

23. Female bracts with only simple trichomes; margin crenate-denticulate ........................................ A. indica L.

— Female bracts with simple and glandular trichomes; margin dentate .......................................................... 24

24. Female bracts with c. 23 teeth, teeth falcate .............................................. A. fimbriata Schumach. & Thonn.

— Female bracts with 7-15 teeth, teeth straight ............................................................................................. 25

25. Female bracts 2-5, central tooth prominent .............................................................. A. bailloniana Müll.Arg.

— Female bracts 7-15, central tooth not prominent ....................................................................................... 26

26. Male inflorescence segment c. 2 mm long; female bracts 12-15, to 2 × 4 mm, teeth 9-11, broadly triangular ............................................................................. A. lanceolata Willd. var. glandulosa (Müll.Arg.) Radcl. -Sm.

— Male inflorescence segment to 10 mm long; female bracts 16-20, to 5 × 6 mm, teeth 7-8, narrowly triangular .................................................................................................................................. A. poiretii Spreng.

27. Leaf blades and/or female bracts with glandular trichomes; androgynous inflorescences with male segment deciduous (inflorescences may appear to be female) ...................................................................................... 28

— Leaf blades and female bracts with only simple trichomes; androgynous inflorescences with male segment persistent ........................................................................................................................................................ 29

28. Leaf blades with glandular trichomes; androgynous inflorescences axillary; female bracts subentire to crenate ........................................................................................................................... A. rottleroides Baill. (in part)

— Leaf blades without glandular trichomes; androgynous inflorescences terminal (on lateral branches, sometimes appearing leaf-opposed); female bracts dentate .................................................... A. spachiana Baill. (in part)

29. Androgynous inflorescences to 9 cm long, with 4- 15 female bracts ................................. A. boinensis Leandri

— Androgynous inflorescences 1-2 cm long, with 1 female bract ................................................................... 30

30. Female bracts to 5 × 9 mm, entire; bracteoles absent; inflorescences with male segment to 3.5 mm ................ ............................................................................................................. A. gillespieae G.A.Levin & I.Montero

— Female bracts to 2 × 2.5 mm, crenate; bracteoles linear-lanceolate; inflorescences with male segment to 7 mm ............................................................................................................... A. nusbaumeri I.Montero & Cardiel

31. Androgynous inflorescences with 1 female bract at base; flattened resinous glands absent .......................... 32

— Androgynous inflorescences with 2 or more female bracts at base, sometimes 1 in A. claoxyloides and A. medibracteata; flattened resinous glands present or absent (if androgynous inflorescences with 1 female bract, then flattened resinous glands present) .............................................................................................................. 46

32. Solitary axillary female bracts absent; androgynous inflorescences sessile or pedunculate, peduncle more than (2.5-) 5 mm long ....................................................................................................................................... 33

— Solitary axillary female bracts present; androgynous inflorescences usually sessile or subsessile, peduncle to 3 mm long (to 10 mm in A. filiformis) ................................................................................................................. 38

33. Androgynous inflorescences to 7 cm long, sessile or subsessile (peduncle to 2.5 mm in A. richardiana); axillary buds to 1 mm long with perules chartaceous or membranous ................................................................... 34

— Androgynous inflorescences to 3(-6) cm long, with peduncle 5-15 mm long; axillary buds to 2-4 mm long with perules membranous ................................................................................................................................. 36

34. Leaf blades broadly ovate to subtriangular; capsules to 3 mm diameter with long projections to 3.5 mm long ..................................................................................................................... A. tremula I.Montero & Cardiel

— Leaf blades elliptic to ovate-lanceolate; capsules to 2 mm diameter without long projections (only with papillae to 0.5 mm long) ........................................................................................................................................ 35

35. Branches erect, densely pubescent; petioles 2-6(-9) cm long, no canaliculate, densely pubescent ................... .......................................................................................................................... A. richardiana Baill. (in part)

— Branches flexuous, glabrous; petioles (0.4-)0.7-1.4 (-1.7) cm long, canaliculate, glabrous ............................... .............................................................................................................................. A. gracilipes Baill. (in part)

36. Female bracts to 8 mm wide, dentate to subentire; axillary buds subfusiform ................ A. humbertii Leandri

— Female bracts to 12 mm wide, entire; axillary buds spherical ..................................................................... 37

37. Leaf blades 5-10 cm long, acuminate to subacuminate .............. A. mayottensis I.Montero & Cardiel (in part)

— Leaf blades 3.5-6(-8.5) cm long, abruptly acuminate ......................................................... A. perrieri Leandri

38. Leaf blades (6-)7-17(-22) cm long; branches never flexuous ...................................................................... 39

— Leaf blades (1.5-)2.5-7.5(-10) cm long (rarely to 11 cm long in A. urophylla), if longer than 7 cm long, then branches usually flexuous .......................................................................................................................... 41

39. Leaf blades broadly ovate-lanceolate, base cordate .................. A. ankaranensis I.Montero & Cardiel (in part)

— Leaf blades ovate-lanceolate to elliptic-lanceolate, base rounded to obtuse ................................................. 40

40. Female bracts usually to 10 mm long (sometimes to 20 mm), margin dentate with or without prominent central tooth .................................................................................................................. A. pervilleana Baill. (in part)

— Female bracts to 7 mm long, margin subentire, without prominent central tooth ....................................... ....................................................................................................................... A. richardiana Baill. (in part)

41. Solitary female bracts long-pedunculate .............................................................................. A. filiformis Poir.

— Solitary female bracts sessile ...................................................................................................................... 42

42. Branches glabrous; mature female bracts to 4 × 3.5 mm, bracteoles present; leaf blade apices obtuse, lower surface glabrous; male bracts glabrous; androgynous inflorescences to 2 cm long ................................................. ........................................................................................ A. berryi I.Montero, Cardiel & G.A.Levin, sp. nov.

— Branches hairy, glabrescent; mature female bracts to 5-10 × 5-12 mm, bracteoles absent; leaf blade apices subacuminate to acuminate, lower surface hairy, at least on veins, sometimes glabrescent; male bracts sparsely hairy; androgynous inflorescences to 4-6 cm long ............................................................................................... 43

43. Leaf blades (1.5-) 2.5-6.5 cm long, ovate-lanceolate to subtriangular, acumen rounded .............................. 44

— Leaf blades (4-)5-7.5(-11) cm long, ovate to elliptic-lanceolate, acumen acute or mucronate ..................... 45

44. Leaf blades (1.5-)2.5-3.5(-4.5) cm long; lower leaf surface and female bracts with only simple trichomes; female bracts with margin entire to crenate ................................................................................ A. leptomyura Baill.

— Leaf blades (3.5-) 4-6.5 cm long; lower leaf surface and female bracts with simple and minute glandular trichomes; female bracts with margin dentate .................................................... A. levinii I.Montero & Cardiel (in part)

45. Branches straight; female bracts glabrous with reddish margin ...... A. lamiana (Leandri) I.Montero & Cardiel

— Branches usually flexuous; female bracts pubescent without reddish margin ........ A. urophylla Boivin ex Baill.

46. Leaf blades and female bracts with flattened resinous glands; ovary and capsule smooth. ............................ 47

— Leaf blades and female bracts without resinous glands; ovary and capsule papillose to erinaceous. .............. 49

47. Androgynous inflorescences with 2- 6 female bracts; female bracts c. 5 mm long ............... A. chibomboa Baill.

— Androgynous inflorescences with 1-2(-3) female bracts; female bracts 10-12 mm long .............................. 48

48. Leaf blades 3.5-5(-7) cm long, linear-lanceolate to oblong-lanceolate ...... A. medibracteata Radcl. -Sm. & Govaerts

— Leaf blades (5-)6-11(-14) cm long, ovate-lanceolate to elliptic-lanceolate ..................... A. claoxyloides Hutch.

49. Inflorescences androgynous and male ........................................................................................................ 51

— All the inflorescences androgynous ............................................................................................................ 55

51. Androgynous inflorescences with peduncle 10-15 mm long; female bracts with rounded teeth ................. 52

— Androgynous inflorescences sessile; female bracts with acute teeth ............................................................. 53

52. Leaf blades 1.8-2.6(-3) cm long, subrhomboidal ..................................... A. cardielii I.Montero & G.A.Levin

— Leaf blades 7-10(-12.5) cm long, elliptic-lanceolate to subobovate ........................................... A. leonii Baill.

53. Leaf blades 6-16(-21) cm long, apex long-acuminate to caudate; some androgynous inflorescences terminal ........................................................................................................................... A. pervilleana Baill. (in part)

— Leaf blades (4-) 5-7.5 cm long, apex shortly acuminate; all androgynous inflorescences axillary ................. 54

54. Petioles (0.4-) 0.7-1.4 cm long; leaf blades elliptic-lanceolate; capsules to 2 mm diameter, without long projections (only with papillae to 0.5 mm long) ............................................................. A. gracilipes Baill. (in part)

— Petioles (3-) 4-6 cm long, leaf blades broadly ovate to subtriangular; capsule to 3 mm diameter with long projections to 3.5 mm long ...................................................................... A. tremula I.Montero & Cardiel (in part)

55. Androgynous inflorescences sessile or subsessile ......................................................................................... 56

— Androgynous inflorescences pedunculate (peduncle more than 15 mm long) ............................................ 57

56. Leaf blades (6-) 7-9 cm long, broadly ovate-lanceolate, subcordate to cordate at the base; female bracts with acute to subacute teeth, with sessile glands at apex .......................... A. ankaranensis I.Montero & Cardiel (in part)

— Leaf blades (3.5-) 4-6.5 cm long, ovate-lanceolate to elliptic-lanceolate, rounded to subcordate at the base; female bracts with rounded teeth without glands ......................................... A. levinii I.Montero & Cardiel (in part)

57. Female bracts c. 5 mm long ......................................................................... A. magistri I.Montero & Cardiel

— Female bracts 7-19 mm long ..................................................................................................................... 58

58. Leaf blades broadly ovate-lanceolate; androgynous inflorescences with peduncle to 45 mm long .................................................................................................. A. menavody (Leandri) I.Montero & Cardiel

— Leaf blades ovate-lanceolate to elliptic-lanceolate; androgynous inflorescences with peduncle to 15 mm long .... 59

59. Leaf blades 2.5-5.5 cm long; female bracts to 10 × 11 mm, with discolorous margin ..................................... ................................................................................................................. A. burmanii I.Montero & Cardiel

— Leaf blades (3-) 5-10 cm long; female bracts to 19 × 21 mm, without discolorous margin .............................. .................................................................................................. A. mayottensis I.Montero & Cardiel (in part)