Xylopia L.

Johnson, David M. & Murray, Nancy A., 2020, A revision of Xylopia L. (Annonaceae): the species of Madagascar and the Mascarene islands, Adansonia 42 (1), pp. 1-88 : 12-16

Genus Xylopia L.

Systema Naturae, ed. 10, 2: 1250 [+1378] (1759), nom. conserv. — Xylopicrum P.Browne, The Civil and Natural History of Jamaica 250-251 + t. 5, fig. 2 (1756). — Xylopicron, orth. mut., Adans., Familles des Plantes 2: 365 (1763). — Type species: Xylopia muricata L., typ. conserv.

Unona L. f., Supplementum Plantarum 270 (1782). — Bulliarda Neck., Elementa Botanica 2: 321 (1790), nom. superfl., non DC. (1801). — Type species: Unona discreta L. f.

Krockeria Neck., Elementa Botanica 2: 317-318 (1790). — Type species: Unona concolor Willd. (lecto-, designated by Johnson & Murray, PhytoKeys 97: 32 [2018]).

Coelocline A. DC., Mémoires de la Société de Physique et d’Histoire naturelle de Genève 5: 208-209 (1832). — Type species: Coelocline acutiflora (Dunal) A. DC.

Parartabotrys Miq., Flora van Nederlandsch Indië, Eerste bijvoegsel 3: 374 (1861). — Type species: Parartabotrys sumatranus Miq.

Pseudanona (Baill.) Saff., Journal of the Washington Academy of Sciences 3: 17 (1913), as “ Pseudannona ”. — Xylopia section Pseudanona Baill., Adansonia ; Recueil d’Observations botaniques 4: 141-142 (1864). — Type species: Pseudanona amplexicaulis (Lam.) Saff. (lecto-, designated by Safford [1913: 18]).

DESCRIPTION

Trees or shrubs, evergreen or sometimes deciduous, with spiral branching from the main trunk axis.

Indument of simple hairs.

Twigs persistently pubescent to glabrate, sparsely lenticellate, longitudinally wrinkled; nodes with one, or in many species with two-three collateral axillary branches.

Leaves with simple entire blades, chartaceous to coriaceous, base symmetrical, sometimes decurrent on petiole, margins flat, recurved, or revolute, midrib impressed to slightly raised adaxially, raised abaxially, secondary veins distinctly to weakly brochidodromous, petiole short, sub-terete, canaliculate, or flattened.

Inflorescences axillary, occasionally arising from the leafless portions of branches, 1-14-flowered in Madagascar and Mascarene species; peduncles 1-several per leaf axil or absent, pedicels 1-several per peduncle, or arising separately from axil, with 1-4 small caducous to persistent bracts; buds ovoid to linear, obtuse to acute, occasionally falciform.

Flowers bisexual.

Sepals 3, connate at least at the base to form a cuplike calyx much shorter than the petals.

Petals 6, in two series of three, valvate, free; outer petals ovate to linear, flattened to a concave base adaxially, flat but sometimes with a longitudinal ridge abaxially; inner petals slightly shorter and narrower than outer petals, ovate to linear, keeled on both surfaces but becoming concave at the base adaxially and flat at the base abaxially, often narrowed into a short claw.

Stamens 50-400; fertile stamens clavate to oblong, anther connective apex shield-shaped, hemispherical, capitate, or conical, often overhanging anther thecae, rarely rudimentary and not overhanging anther thecae, pubescent or papillate, rarely glabrous, anthers transversely septate, filament much shorter than anther, articulated with the staminal cone; outer staminodes present, oblong to clavate, apex obtuse to obliquely truncate, rarely absent; inner staminodes present, often adhering to the bases of the stigmas, usually shorter than outer staminodes, clavate to oblong, apex rounded, rarely absent; filament bases connate into a staminal cone that partially or completely encloses the ovaries, the rim even or irregularly laciniate, staminal cone rudimentary to absent in a few species.

Carpels separate; ovaries oblong or ovoid, stigmas free or loosely connivent, longer than the ovaries (in Malagasy and Mascarene species).

Torus flat or slightly concave.

Fruits consisting of elongate dehiscent monocarps (dehiscence undocumented for several Malagasy species), these often with a green to red exterior and red endocarp; monocarps sometimes torulose, short-stipitate to sessile.

Seeds up to 9 per monocarp in Madagascar species, attached laterally in one or two rows, ellipsoid, smooth or rugose, the hard brown to black inner layer of the seed coat sometimes covered by a light green or orange sarcotesta, perichalazal ring raised or not visible externally, endosperm ruminations platelike to spinelike, an aril forming fleshy lobes or rings around the micropyle in some species.

NOTES

A pantropical genus of nearly 200 species, represented on Madagascar by 30 endemic species and on the Mascarene Islands by three endemic species. Three of the six sections of Xylopia are represented in the region: sect. Xylopia (species 1-8), sect. Verdcourtia (species 9-10), and sect. Stenoxylopia (species 11-33). Species are listed alphabetically within each section.

KEYS TO THE SPECIES OF XYLOPIA L. FROM MADAGASCAR AND THE MASCARENE ISLANDS

Notes: Vegetative characters are emphasized in the keys because flowers of two species and fruits of four species remain unknown. Reference to the elevational ranges of species in Figure 4 and seed data in Table 1 may be useful aids to identification. As in the species descriptions, the leaf blade dimensions pertain to the larger leaves on a specimen.

KEY TO THE MASCARENE ISLAND SPECIES OF XYLOPIA

1. Leaf blades 4.4-8.8 cm long, 2.6-3.7 cm wide; outer petals 19-37 mm long, 3.5-5 mm wide at midpoint ...... ............................................................................................................................. X. richardii Boivin ex Baill.

— Leaf blades 9.7-23.5 cm long, 5.5-8.4 cm wide; outer petals 31-55 mm long, 11-28 mm wide at midpoint ...... 2

2. Leaf blades cordate-auriculate at the base, lobes clasping the stem ..................... X. amplexicaulis (Lam.) Baill.

— Leaf blades rounded to truncate at the base, not clasping the stem ..................................... X. lamarckii Baill.

KEY TO THE MALAGASY SPECIES OF XYLOPIA

1. Hairs on young twigs, petioles, and pedicels erect or loosely spreading ........................................................ 2

— Hairs on young twigs, petioles, and pedicels appressed, or twigs, petioles, and pedicels glabrous ................. 6

2. Leaf blades with margins flat or slightly recurved; outer petals 1.0- 1.8 mm wide at midpoint ..................... 3

— Leaf blades with margins revolute; outer petals 3.3-4.4 mm wide at midpoint ............................................. 5

3. Leaf blades densely sericeous abaxially, the hairs silvery, apex acuminate or sometimes acute; inflorescences 1-4-flowered ...................................................................................................................... X. lastelliana Baill.

— Leaf blades pubescent abaxially, the hairs brown and dull, apex obtuse, rounded, or retuse, rarely acute; inflorescences always 1-flowered ......................................................................................................................... 4

4. Twigs sparsely covered with persistent erect brown hairs 0.2-0.3 mm long; leaf blades lanceolate to elliptic, obtuse or rarely acute; pedicels 4.3-7.1 mm long; pericarp 0.6-1.2 mm thick, sarcotesta orange ..................... ...................................................................................................................................... X. bemarivensis Diels

— Twigs densely covered with persistent erect ferruginous hairs 0.3-1.2 mm long; leaf blades ovate to elliptic, retuse and sometimes truncate; pedicels 2.9-4 mm long; pericarp 3.0- 3.1 mm thick; sarcotesta pale green ................... ......................................................................................................................... X. lamii Cavaco & Keraudren

5. Leaves strongly revolute, pubescence of twigs, leaves, inflorescences, and monocarps dull red; petiole 5-10 mm long ........................................................................................................... X. capuronii Cavaco & Keraudren

— Leaves slightly revolute, pubescence of twigs, leaves, inflorescences, and monocarps pale brown; petiole 3-4 mm long ......................................................................... X. kalabenonensis D.M.Johnson, Deroin, & Callmander

6. Leaf blades small, <6 cm long AND <3 cm wide ....................................................................................... 7

— Leaf blades either> 6 cm long OR> 3 cm wide ........................................................................................ 19

7. Leaf blades acute to acuminate at the apex .................................................................................................. 8

— Leaf blades obtuse, rounded, emarginate, or retuse at the apex .................................................................. 13

8. Leaf blades glabrous or with a few scattered hairs abaxially ....... X. humbertii Ghesq. ex Cavaco & Keraudren

— Leaf blades appressed-pubescent abaxially ................................................................................................... 9

9. Leaf blades with appressed hairs that are longer and more spreading along midrib and margins, abruptly sharpacuminate; outer petals linear, 0.7-1.4 mm wide at midpoint .................................................................... 10

— Leaf blades with appressed hairs of uniform length abaxially, acumen gradual, short, and blunt; outer petals lanceolate, 1.2-2.7 mm wide at midpoint .................................................................................................. 11

10. Base of leaf blade cuneate, inner petals straight and needle-like ........................................... X. lemurica Diels

— Base of leaf blade broadly cuneate to rounded, inner petals narrowly sinuous ................................................. ............................................................................................................ X. ghesquiereana Cavaco & Keraudren

11. Petiole 5.5-8 mm long; pedicels 2.5-3.2 mm long; anther connective apex rudimentary, not overhanging anther thecae; carpels 2-3 ................................................................................. X. sahafariensis Cavaco & Keraudren

— Petiole 1.3-6 mm long; pedicels 3.6-9 (-11.3) mm long; anther connective apex shield-shaped or capitate, overhanging anther thecae; carpels 7-11 ........................................................................................................... 12

12. Leaves sparsely appressed-pubescent abaxially; axillary branches always one per node; monocarps narrowly oblong to cylindrical, 0.7-1.1 cm wide ............................................... X. madagascariensis Cavaco & Keraudren

— Leaves densely appressed-pubescent abaxially; axillary branches often two per node; monocarps oblong to pyriform, 1.3-2.1 cm wide ........................................................................................................ X. perrieri Diels

13. Leaf blades sericeous abaxially, the hairs silvery abaxially............................................................................. ............................................................................. X. sclerophylla D.M.Johnson & N.A.Murray , sp. nov.

— Leaf blades appressed-pubescent the hairs dull colored, or glabrous abaxially ............................................. 14

14. Leaf blades narrowly oblong, elliptic, oblanceolate, or linear-lanceolate, length to width ratio> 3:1, apex always retuse ................................................................................... X. retusa D.M.Johnson & N.A.Murray , sp. nov.

— Leaf blades broader, elliptic, obovate, oblanceolate, or rarely lanceolate, length to width ratio <3:1, apex obtuse, rounded or occasionally retuse ................................................................................................................... 15

15. Outer petals linear to linear-lanceolate, 1.0- 1.8 mm wide at midpoint ...................................................... 16

— Outer petals lanceolate or narrowly oblong, (1.4-) 2.0- 4.1 mm wide at midpoint ..................................... 17

16. Leaf blades truncate or rounded at base; monocarp 1, conspicuously veined longitudinally, pyriform, oblong, or ovoid .......................................................................................................................... X. sericolampra Diels

— Leaf blades cuneate to broadly cuneate at base; monocarps up to 7, smooth, ovoid to broadly elliptic ............ ............................................................................................................................................ X. buxifolia Baill.

17. Leaf blades widest at or proximal to the midpoint; monocarps oblong to pyriform, 1.3-2.1 cm wide ............. .............................................................................................................................................. X. perrieri Diels

— Leaf blades widest at or distal to the midpoint; monocarps narrowly oblong to clavate, 0.8-1.2 cm wide ...... 18

18. Pedicels and sepals densely pubescent; outer petals lanceolate; pedicel of fruit 13-19 mm long ....................... ................................................................................. X. ravelonarivoi D.M. Johnson & N.A. Murray , sp. nov.

— Pedicels and sepals sparsely appressed-pubescent; outer petals narrowly oblong; pedicel of fruit 8-11 mm long ...... ...................................................................................................................................... X. humblotiana Baill.

19. Leaf blade length to width ratio> 3.5:1 ..................................................................................................... 20

— Leaf blade length to width ratio <3.5:1, often much less ........................................................................... 22

20. Leaf blades 8.7-17.2 cm long, 2.2-4.4 cm wide, secondary and higher-order veins strongly raised and forming a conspicuous vein reticulum on both surfaces .................. X. australis D.M.Johnson & N.A.Murray , sp. nov.

— Leaf blades 6.4-8.8 cm long, 1.5-2.2 mm wide, secondary and higher-order veins indistinct or slightly raised, not forming a conspicuous reticulum on either surface .............................................................................. 21

21. Monocarps densely lenticellate, ovoid to ellipsoid, 2.3-2.6 cm wide, leaf acumen forming ¼-¹⁄5 of leaf blade length; littoral forests and nearby hills of eastern Madagascar......................................................................... ....................................................................................... X. longirostra D.M.Johnson & N.A.Murray , sp. nov.

— Monocarps sparsely lenticellate, oblong to obovoid, 1.3-1.8 cm wide; leaf acumen forming ¹⁄6-1/8 of leaf blade length; dry forests of northern Madagascar............................................ X. ambanjensis Cavaco & Keraudren

22. Bark of leafy twigs exfoliating, leaf blade long-decurrent on petiole ................................................................ .................................................................................... X. marojejyana D.M.Johnson & N.A.Murray , sp. nov.

— Bark of leafy twigs smooth or with occasional flaking patches, leaf blade short-decurrent or not decurrent on petiole ....................................................................................................................................................... 23

23. Pedicellar bracts 2, one attached at midpoint and often caducous, the other immediately subtending the sepals and persistent ............................................................................................................................................ 24

— Pedicellar bracts 2-4, attached at various points but never immediately subtending the sepals ................... 27

24. Sepals <4 mm long ................................................................................................................................... 25

— Sepals> 4 mm long ................................................................................................................................... 26

25. Leaf blades 8.7-15 cm long, 2.9-6.5 cm wide, anther connective apex shield-shaped, overhanging anther thecae ........................................................................................... X. danguyella Ghesq. ex Cavaco & Keraudren

— Leaf blades 4.9-8.6 cm long, 1.5-3.3 mm wide, anther connective apex rudimentary, not overhanging anther thecae .................................................................................................... X. sahafariensis Cavaco & Keraudren

26. Outer petals with a distinct longitudinal ridge on the abaxial surface, 2.9-3.7 mm wide at midpoint; leaf blades slightly revolute at margins, sharply acuminate, midrib distinctly impressed adaxially; eastern Madagascar.... .......................................................................................... X. carinata D.M.Johnson & N.A.Murray , sp. nov.

— Outer petals flat or with an indistinct longitudinal ridge on the abaxial surface, 1.8-3 mm wide at midpoint; leaf blades flat at margins, obtuse or blunt-acuminate, midrib flat adaxially; northwestern Madagascar.......... ........................................................................................ X. lokobensis D.M.Johnson & N.A.Murray , sp. nov.

27. Leaf blades> 5.5 cm wide; flowers up to 5 per inflorescence; outer petals ovate, 8.6-9 mm long, monocarps densely lenticellate ............................................................ X. anomala D.M.Johnson & N.A.Murray , sp. nov.

— Leaf blades <5.0 cm wide; flowers 1-4 per inflorescence; outer petals linear to lanceolate, 10-28 mm long; monocarps sparsely lenticellate or lacking lenticels .................................................................................... 28

28. Leaf blades truncate or rarely rounded at the base, not decurrent on petiole; emerging shoots densely covered with silvery hairs; anther connective apex rudimentary, not overhanging anther thecae; monocarp strongly marked with longitudinal veins when dried .................................................................... X. sericolampra Diels

— Leaf blades cuneate, broadly cuneate, or rounded at the base, sometimes short-decurrent on petiole; emerging shoots sparsely pubescent to glabrous, hairs dull in color; anther connective apex shield-shaped to capitate, overhanging anther thecae, monocarps smooth to wrinkled but lacking longitudinal veins ........................ 29

29. Leaf blades appressed-pubescent abaxially, with longer hairs present along the midrib and margins; outer petals 0.7-1.4 mm wide at midpoint ............................................................................................. X. lemurica Diels

— Leaf blades glabrous to nearly so or, if appressed-pubescent, then hairs all of equal length; outer petals 1.2- 5.5 mm wide at midpoint ......................................................................................................................... 30

30. Leaf apex obtuse, rounded, retuse, or emarginate ...................................................................................... 31

— Leaf apex acute to acuminate ..................................................................................................................... 32

31. Pedicels and sepals densely pubescent; outer petals lanceolate; pedicel of fruit 13-19 mm long; elevations above 500 meters ................................................................ X. ravelonarivoi D.M.Johnson & N.A.Murray , sp. nov.

— Pedicels and sepals sparsely appressed-pubescent; outer petals narrowly oblong; pedicel of fruit 8-11 mm long; elevations of 50 meters or less ........................................................................................ X. humblotiana Baill.

32. Outer petals 12.6-14.6 mm long; stamens c. 80 ....................... X. humbertii Ghesq. ex Cavaco & Keraudren

— Outer petals (13.5-) 16-28 mm long; stamens 80-200 ............................................................................... 33

33. Seeds arillate; staminal cone 2.0- 3.9 mm in diameter, 0.9-1.7 mm high, much wider than high, with an even rim ................................................................................................................................................... 34

— Seeds not arillate; staminal cone 1.0- 2.4 mm in diameter, 0.6-1.8 mm high, slightly wider than high, rim irregularly laciniate ...................................................................................................................................... 36

34. Bracts on pedicel persistent, even into the fruiting stage; flowers often arising from tubercles on leafless growth .................................................................................................................................. X. flexuosa Diels

— Bracts on pedicel caducous; flowers borne on leafy twigs ........................................................................... 35 35. Leaf blades 6.5-12.7 cm long, 2.5-4.8 cm wide ...................................... X. beananensis Cavaco & Keraudren

— Leaf blades 5.2-6.6 cm long, 1.8-2.7 cm wide ................................ X. madagascariensis Cavaco & Keraudren

36. Leaf blades chartaceous, obovate, oblanceolate, or oblong-obovate, rounded to broadly cuneate at the base; petiole deeply canaliculate; monocarps 0.8-1.1 cm wide, obliquely wrinkled, not verrucose, glabrate ............. ........................................................................................................................ X. dielsii Cavaco & Keraudren

— Leaf blades subcoriaceous, elliptic to elliptic-oblong, cuneate at the base; petiole shallowly canaliculate; monocarps 1.9-3.2 cm wide, faintly wrinkled, verrucose, and brown-pubescent ................................................. 37

37. Shrub; flower pedicels 2-4.5 mm long; monocarps with a narrow stipe 4-5 mm long and 2.8-4.8 mm thick, apex with a broad beak 1.5-3 mm long .................... X. galokothamna D.M.Johnson & N.A.Murray , sp. nov.

— Tree; flower pedicels 6-8.7 mm long; monocarps sessile or with a broad stipe 2-3 mm long and 4-8 mm thick, apex rounded, obtuse, or truncate ..................................................... X. fananehanensis Cavaco & Keraudren

Figures

FIG. 4. — Elevational ranges in meters for the 30 Madagascar Xylopia L. species,with midpoint value indicated by an orange dot. Individual species are indicated by the first four letters of the specific epithet in all capital letters,except for combinations HUML and HUMR used to distinguish X. humblotiana Baill. and X. humbertii Ghesq. ex Cavaco & Keraudren, respectively.