Xylopia lamarckii Baill.

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 : 28-30

5. Xylopia lamarckii Baill.

( Figs 1H-I ; 5 ; 6E ; 10 )

Adansonia; Recueil d’Observations botaniques 4: 142, 143 (1864). — An [n] ona grandiflora Lam., Encyclopédie méthodique, Botanique 2 (1): 126, 127 (1786). — Pseudanona [“ Pseudannona ”] grandiflora (Lam.) Saff., Journal of the Washington Academy of Sciences 3: 18 (1913). — Xylopia grandiflora (Lam.) Ghesq. ex Cavaco & Keraudren, Flore de Madagascar et des Comores, Annonacées, vol. 78: 26 (1958) , non A.St.-Hil. (1825). — Type: “ Isle de Bourbon ”, s. d. (fl.), Commerson s. n. (lecto-, P [ P0034246 ]!; isolecto-, P[P0034247]!).

ṙ An [n] ona grandiflora * madagascariensis Pers. , Synopsis Plantarum seu Enchiridium Botanicum 2 (1): 95 (1806). — Type: Hab. in ins. Madagasc., herb. Juss[ieu] (not found).

Annona pyriformis Bojer ex Baker, Flora of Mauritius and the Seychelles 3 (1877). — Type: Mauritius. Without definite locality, Bojer s. n. (not found).

MATERIAL EXAMINED. — Mauritius. “Dans l’infonumene delaplace de Hollandois au Pon du P. E. habitation du Prahy” [ṙ], 29.IX.1754 (fl.), Aublet s. n. ( BM) ; Moka ( Vuillemin ), 15.I.1924 (old fl.), Bijoux s. n. (P[P01987045]) ; native of mountain woods of Nouvelle Decouverte , s. d. (fl.) [presented 17.VII.1863], Blackburn herb. [ex Bojer?] (K) ; in campis sylvestribus insula Mauritii , s. d. (st.), ex herb. Bojer [er], ( BM) ; “isle de france”, without definite locality, s. d. (st.), Commerson s. n. (P[P030400]); Grand Bassin , 31.I.1933 (st.), Duhamel 16139 ( MAU) ; Crown Land Perrier , s. d. (bud), Duljeet 16140 ( MAU) ; Ripailles , II.1862 (fl.), Dupont [coll. Ayres?] s. n. (K) ; Ravine Cascade , 500 ft, V.1971 (st.), Friedmann 1202 (P[P01987041]) ; without definite locality, s. d. (fl., st.), Herb. Du Petit-Thouars s. n. (P[P01987042, P01987048]); “ Ile de France ”, s. d. (fl.), Herb. E. Drake (ex Herbarium Richard) s. n. (P[P01987044]) ; without definite locality, s. d., Herb. R. Botanic Gardens Pamplemousse (st., collector unknown) 14, (st., Bouton) 15, (st., Bijoux) 16, (old fl., Bijoux) 17, (all MAU) ; Pétrin Nature Reserve (S. W.), 2000 feet, 6.I.1973 (fl.), Lorence M 23 ( MO, WAG) ; Pétrin Nature Reserve , 12.XII.1978 (fl.), Lorence 2124 (K n.v., MAU, MO, P[P01987040], US) ; Perrier Nature Preserve near Mare aux Vacoas , 600 m, 28.XII.1978 (fl.), Lorence 2225 (K n.v., MAU, MO, P[P01987046]) ; Gaulettes Serrées , 400-450 m, 19.V.1979 (st.), Lorence et al. 2635 ( MAU) ; Brise Fer, west edge of Central Plateau , 600 m, 1.VI.1979 (st.), Lorence s. n. ( MAU) ; Petrín Nature Reserve , 24.II.1972 (fl.), Owadally 15115 ( MAU) ; Perrier Nature Reserve , 17.II.1971 (fl.), Vaughan 15228 ( MAU) ; La Villebague, s. d. (buds), Wallich s. n. ( BM) ; Grand Port, s. d. (fl.), Wallich s. n. ( BM) ; without definite locality, s. d. (fl.), collector unknown, ex herb. Lambert ( BM, 2 sheets) .

DISTRIBUTION, ECOLOGY AND CONSERVATION STATUS. — Endemic to the island of Mauritius, Xylopia lamarckii occurs in thickets and in the upland heath and dwarf forest of Philippia and Phylica over laterite, sometimes with emergent Sideroxylon and Calophyllum ( Kaiser 2006), at elevations of 150-700 meters ( Fig. 7 ). Specimens with flowers have been collected from December to February. Xylopia lamarckii was given a status of Critically Endangered by Page (1998b), who estimated the population at that time as 250 individuals. Our EOO and AOO calculations of 270 km 2 and 32 km 2, respectively, support that status, as does the lack of effective pollinators described below.

LOCAL NAME. — Bois blanc (Aublet s. n.).

DESCRIPTION

Treelet or shrub up to 4 m tall, often sprawling or subscandent; d.b.h. up to 2 cm.

Twigs sparsely appressed-pubescent, the hairs c. 0.2 mm long, soon glabrate; nodes with a single axillary branch.

Leaves with larger blades 11.5-23.5 cm long, 6.2-8.4 cm wide, chartaceous, discolorous, olive-gray adaxially, dull orange-brown and occasionally somewhat glaucous abaxially, lanceolate to ovate, apex acute to acuminate, the acumen 8-26 mm long, base rounded to truncate, occasionally subcordate, not decurrent, margin flat, not revolute, glabrous adaxially, sparsely pubescent on the midrib but otherwise glabrous abaxially; midrib light brown toward the base adaxially, secondary veins weakly brochidodromous, 12-20 per side, diverging at 60-70° from midrib, these and higher-order veins slightly raised and forming a conspicuous reticulum on both surfaces; petiole 3-6 mm long, semi-terete, transversely wrinkled, sparsely pubescent to glabrate.

Inflorescences axillary, 1-flowered, not pedunculate, appressedpubescent; pedicels 8-13 mm long, 2-2.6 mm thick; bracts 2-3, one attached near the pedicel midpoint and the others near the pedicel base, caducous; buds oblong to obovoid, apex obtuse, occasionally slightly falciform.

Sepals spreading at anthesis, ¹⁄5-1/2-connate, 4.5-10 mm long, 6.5-12 mm wide, coriaceous, broadly triangular-ovate, apex acute to obtuse, appressed-pubescent abaxially.

Petals creamy white, sometimes flushed with rose, with a purple spot at the base adaxially in vivo; outer petals slightly spreading at anthesis, 32-55 mm long, 5-12.5 mm wide at base, 11-28 mm wide at midpoint, fleshy, lanceolate, oblong, or oblanceolate, flattened toward the base adaxially, apex obtuse, densely puberulent on apical half and along margins to the base adaxially, uniformly appressed-pubescent abaxially; inner petals slightly spreading at anthesis, 29-41 mm long, c. 4.7 mm wide at base, 3-10 mm wide at midpoint, fleshy, narrowly oblong, laterally compressed, keeled at apex adaxially, sharply keeled abaxially, apex acute, base deeply concave with undifferentiated margin, densely puberulent at apex but glabrous toward base adaxially, thinly appressed-pubescent at apex and along keel abaxially.

Stamens c. 300; fertile stamens 1.3-1.9 mm long, narrowly oblong, anther connective apex c. 0.2 mm long, capitate or shield-shaped, overhanging the anther thecae, papillate, anthers 10-12-locellate, filament 0.4-0.5 mm long; outer staminodes 1.3-1.6 mm long, clavate, apex truncate; inner staminodes c. 1.2 mm long, oblong, quadrate, or clavate, apex truncate; staminal cone 5-6 mm in diameter, 1.5-4 mm high, completely concealing the ovaries, rim even.

Carpels c. 20; ovaries c. 1.5 mm long, narrowly oblong, tomentose, stigmas basally connivent with the tips free, 9.5- 11 mm long, filiform, glabrous or with a few scattered hairs.

Fruit (ex Keraudren-Aymonin 1980) “Fruit mal connu, à monocarpes d’environ 3.5 × 0.8 cm, glabres.

Seeds (Keraudren-Aymonin 1980) “Graines arillées, longues de 11-12 mm ”.

NOTES

The large broad fleshy petals of Xylopia lamarckii sets it apart from all other Xylopia species of the Madagascar and Mascarene region with the exception of the Mauritian species X. amplexicaulis , from which it is distinguished by the distinctly petiolate leaves that are rounded to truncate at the base. The distinctive floral structure led to the initial description of both species in the genus Annona by Lamarck (1786), and was the basis for segregating them in a new section Pseudanona when Baillon (1864) transferred them from Annona to Xylopia . Additional floral characters that place both species securely in Xylopia include axillary inflorescences, septate anthers, and a well-developed staminal cone surrounding the ovaries. The phylogenetic analysis of Stull et al. (2017) showed X. lamarckii nested well within the Xylopia clade on the basis of molecular data.

Apart from the nature of the leaf base, X. lamarckii and X. amplexicaulis are similar, and in fact some specimens of X. lamarckii have a relatively short petiole and a subcordate base of the leaf blade. Both species have been reported from Nouvelle Découverte ( Bojer 1837), the Perrier Nature Preserve near Mare aux Vacoas, Grand Port, and Gaulettes Serrées. As indicated by the report of Aublet (1775), X. lamarckii was also once common in the vicinity of Port Louis and Moka.

As part of a larger study of pollinator webs in Black River Gorges National Park in Mauritius, Kaiser (2006, Kaiser-Bunbury et al. 2009) examined floral phenology and floral visitors for Xylopia lamarckii . He documented the narrow flowering period from December to January, and noted that fruit set was not observed. Floral visitors includ- ed only one species of ant and one species of Chrysomelid beetle, both introduced and both found on flowers of a wide range of species at the study site. The flowers have a fruity-spicy odor (Lorence 2225). The habitat in the pollinator study site was dwarf forest dominated by Erica and Phylica spp., with emergent Sideroxylon and Calophyllum spp., an endangered habitat on the island.

The provenance of the type material of Annona grandiflora Lamarck is uncertain. Lamarck (1786) cited the Commerson collections he examined as having come from Madagascar and La Réunion (“isle de Bourbon”). Specimens at P collected by Commerson are labeled as coming from La Réunion and Mauritius (“isle de france”). Because X. lamarckii has never been collected again from either La Réunion or Madagascar, those attributions are set aside as labeling errors, as has been concluded previously ( Cavaco & Keraudren 1958, Keraudren-Aymonin 1980).

Lamarck (1786) described the fruit and seeds: “Le fruit est médiocre, ovoïde, à écorce glabre, légérement ponctuée ou chagrinée. Il contient des semences oblongues, pointues, tranchantes du côte intérieur, avec deux faces applaties, convexes & plus épaisses sur leur dos; ces semences sont disposées en petit nombre dans la longueur du fruit, & enveloppées d’une pulpe médiocre”. Dunal (1817; Fig. 10[26, 27]) illustrated a single sessile ovoid monocarp, with the calyx persistent around its base, and a longitudinal section of the fruit showing five depressions in which the seeds sat. The seed illustrated (Fig. 10[31]) is narrowly obovoid, smooth, truncate at one end and pointed at the other. He did not, however, identify the source material for the drawings. It is possible that the dimensions given by Keraudren-Aymonin (1980) for the fruit, “d’environ 3.5 × 0.8 cm ”, and for the seed, “longues de 11-12 mm ”, were estimated from this drawing. Fruits and seeds are not attached to any of the specimens we examined.

The name An [n] ona grandiflora * madagascariensis of Persoon was based on a specimen in the Jussieu Herbarium that we have not located. The name is listed as a synonym of X. lamarckii because past authors ( Dunal 1817, Keraudren-Aymonin 1980) have attributed it that way, but we were not able to confirm the identification. The short diagnosis, “fol. ovatis coriaceis integerrimis lucidis”, does not provide adequate details for confirmation.

Baker (1877) gave a brief, but validating, description of Annona pyriformis , a nomen nudum listed by Bojer (1837). With the exception of the statement that the inner and outer petals are subequal, the description conforms to that of X. lamarckii , and Keraudren-Aymonin (1980) placed the name in synonymy. Type material has not been found, although a specimen at BM, BM000510673, is stated on the label as having come from the Bojer herbarium. The only plant name given on the label, however, is “ Anona grandiflora DC. Prod.” This specimen does not seem supportable as a lectotype of A. pyriformis without additional information.

The specimens from the Lambert Herbarium now at BM have no indication of the collector, but according to Miller (1970) there were specimens in the Lambert Herbarium collected in Mauritius by Colebrooke, Hardwicke, Hilsenberg (part of Sieber collection), and A. Michaux. Both specimens have the name “ Michelia rufinervis Decand. Syst.” Written in faint pencil at the bottom; this name was based on a specimen collected from a cultivated plant in Mauritius by Commerson ( Candolle 1817).

Figures

FIG. 1. — Aspects of Xylopia L. vegetative and floral morphology: A, shrub habit of X. humblotiana Baill.; B, habit of X. bemarivensis Diels, showing several nodes with both collateral buds forming shoots, creating pseudo-opposite branches; C, flowers of X. lastelliana Baill., showing inner petals bent outward through the gaps between outer petals (Schatz & Modeste 2877); D, flowers of X.perrieri Diels showing conspicuous red coloration at the bases of the outer petals (Schatz & O’Connor 2964); E, spreading outer petals and erect inner petals of X. kalabenonensis D.M.Johnson, Deroin, & Callmander (Razafitsalama et al. 1041); F, flower of X. richardii Boivin ex Baill., with stigmas emerging in the center amidst the inner petals; G, inflorescences of X. beananensis Cavaco & Keraudren, showing a bud, two flowers with petals, stamens, and stigmas fallen so that the staminal cone is visible, and one open flower (Buerki 14); H, open flower of X. lamarckii Baill.; I, open flower of X. lamarckii with one outer petal and one inner petal removed to show interior of flower, including stamens and stigmas. Photos: A, M. C. Andriamahay; B, F. Rakotoarison; C, D, G. E. Schatz; E, J. Razafitsalama; F, H, I, C. Kaiser-Bunbury; G, M. W. Callmander. A, B, used under the terms of the Creative Commons license for iNaturalist; C-E, G, used under the terms of the Creative Commons license for Tropicos, the botanical information system at the Missouri Botanical Garden.

FIG. 5. — Xylopia amplexicaulis (Lam.) Baill. and X. lamarckii Baill. A-H, X. amplexicaulis: A, habit; B, C, flower, longitudinal section showing carpels, staminal cone, inner petals, and outer petals; D, outer petal, adaxial view; E, inner petal, adaxial view; F, stamen, abaxial view; G, fruit; H, seed, side view; I, X. lamarckii, habit. Flowers and fruits are based on fluid-preserved specimens, and the sizes are larger than indicated in the species descriptions. A, From Commerson s. n. (P); B-F, from Bosser 21824 (P, spirit collection and photograph); G, H, from Lorence 1180 (MAU, spirit collection); I, from Commerson s. n. (P). Figure reproduced from Keraudren-Aymonin 1980, re-used with permission of T. Mourier, Service Editions, Mission culture scientifique et technique, Institut de recherche pour le développement (IRD), Montpellier. Scale bars: A, B, D, E, G, I, 3 cm; C, H, 2 cm; F, 1 mm.

FIG. 6. — A, Shoot of X. amplexicaulis (Lam.) Baill., showing flower bud at left and clasping leaf bases visible at several nodes; B, branch of X. ravelonarivoi, sp. nov., with fruit (Ravelonarivo 4171); C, flower of X. humblotiana Baill., side view (Schatz 4475); D, buds of X. richardii Boivin ex Baill.; E, close-up of flower interior of X. lamarckii Baill., showing red coloration at bases of petals, and the stamens and stigmas; outer staminodes are visible along the edge of the androecium; F, flower of X. richardii at anthesis, one outer petal and one inner petal removed, so that androecium and stigmas are visible; G, leaves and fruit of X. anomala, sp. nov., (Rakotonirina 48); H, leaves and fruit of X. sericolampra Diels. Photos: A, Carlos Magdalena; B, D. Ravelonarivo; C, G. E. Schatz; D-F, C. Kaiser-Bunbury; G, C. Birkinshaw; H, R. N. Rabarijaona. B, C, G, used under the terms of the Creative Commons license for Tropicos, the botanical information system at the Missouri Botanical Garden; H, used under the terms of the the Creative Commons license for iNaturalist.

FIG. 10. — Plate 6A from Dunal (1817), showing the only fruit and seed details known for Xylopia lamarckii Baill.

FIG. 7. — Distributions of Xylopia amplexicaulis (Lam.) Baill., X. lamarckii Baill., and X. richardii Boivin ex Baill. on the islands of La Réunion and Mauritius.