Croton chapelieri Baill.

Kainulainen, Kent, Berry, Paul E. & Ee, Benjamin van, 2017, Rediscovery of two species of Croton (Euphorbiaceae) from littoral habitats of eastern Madagascar, Candollea 72 (1), pp. 35-44 : 37-39

Croton chapelieri Baill. in Adansonia 1: 166. 1861 ( Fig. 1 , 2 , 4 A-F, 5A-B).

Ξ Oxydectes chapelieri (Baill.) Kuntze, Revis. Gen. Pl. 2: 611. 1891.

– Aubertia glandulosa Chapel. ex Baill. in Adansonia 1: 166. 1861 [nom. nud.].

Typus: MADAGASCAR: Prov. Toamasina: sine loc., Chapelier s.n. (holo-: P [ P00389523 ]!).

Epitypus (designated here): MADAGASCAR. Prov. Toliara: Sainte Luce, at entrance to reserve just past thatched huts, 24°46’46”S 47°10’17”E, 10 m, 17.II.2009, van Ee, Berry, Dorsey & Razanatsoa 925 ( MICH [ MICH1514617 ]!; isoepi-: G!, K!, MAPR!, MO!, NY!, P!, TAN!).

= Croton louvelii Leandri in Ann. Mus. Colon. Marseille, sér. 5, 7: 40. 1939. Typus: MADAGASCAR. Prov. Toamasina: forêt côtière, Tampina, I.1924, Louvel 217 (holo-: P [P00312340]!) [as louveli], syn. nov.

= Croton aymoninorum Leandri in Adansonia ser. 2, 13: 175. 1973. Typus: MADAGASCAR. Prov. Toliara: Fort Dauphin, forêt de Mandena, 19.X.1970, Keraudren-Aymonin & Aymonin 24940 (holo-: P [P00312374]!), syn. nov.

= Croton daphniphylloides Radcl. -Sm., Gen. Croton Madag. Comoro: 164. 2016. Typus: MADAGASCAR. Prov. Toamasina: Ambila-Lemaitso, 7.XI.1951, Service Forestier 4228 (holo-: P [P00133469]!), syn. nov.

= Croton daphniphyllum Radcl. -Sm., Gen. Croton Madag. Comoro: 161. 2016. Typus: MADAGASCAR. Prov. Toliara: Fort Dauphin in Mandena, 2 km E of Botanic Garden, 24°58’S 47°00’E, 9.X.1990, Faber-Langendoen, Dumetz & Randrianasolo 2226 (holo-: P [P00133462]!; iso-: MO!), syn. nov.

= Croton daphniphyllum var. hirsutus Radcl. -Sm., Gen. Croton Madag. Comoro: 163. 2016. Typus: MADAGASCAR. Prov. Toliara: Petriky Forest, c. 1.5 km W of large dune near N shore of Lake Andranany, c. 12 km WSW of Tôlañaro [Fort Dauphin], 25°03’S 46°53’E, 14.IV.1989, Gereau, Rabevohitra & Dumetz 3374 (holo-: K!; iso-: MO!, P [P00133120]!), syn. nov.

= Croton rhododendroides Radcl. -Sm., Gen. Croton Madag. Comoro: 163. 2016. Typus: MADAGASCAR. Prov. Toliara: Préfecture Tôlañaro (Fort Dauphin), forêt à 5 km de Ste. Luce, au N de Maliafolaky, 24°47’S 47°10’E, 21.X.1989, Dumetz, McPherson & Rabevohitra 775 (holo-: P [P00133460]!; iso-: MO!), syn. nov.

Shrubs or trees to 10 m tall, with bifurcating branching. Branches ± flattened on new growth but becoming terete with age, gray, usually sparsely covered with brown stellate-lepidote indumentum (hairs sometimes with a porrect central radius, resulting in the young shoot being villous). Stipules absent or vestigial. Leaves alternate along stem, but (sub)opposite and ± whorled towards the apex. Petioles 4-40(60) mm long, adaxially canaliculate, sparsely brown stellate-lepidote (sometimes villous), usually with a pair of ± stipitate (0.1- 1 mm) concave discoid glands 0.5-1.0 mm in diam. at the base of the blade. Leaf blades coriaceous, slightly revolute, entire or serrate towards the apex, elliptic to obovate or occasionally lance-obovate, 2.8-15.5 × 1.5-6.5 cm, apex (acuminate) apiculate or acute to rounded, base cuneate or rounded; adaxial surface glabrous, glossy, bright green with a pale green or reddish midrib when fresh, turning orange in old leaves, drying ± glossy, brown or olive green; venation usually readily seen, with 3-11 pairs of brochidodromous, ± penninerved secondary veins; abaxial surface glabrous or sparsely brown stellate-lepidote (in particular along the midrib), pale green; venation and midrib ± prominent. Inflorescences short racemes 1.0-4.0(-7.5) cm long, terminal, bisexual, the staminate flowers towards the distal end and more numerous than the 1-6(8) pistillate flowers at the base, generally divergent; axes stellate-lepidote (sometimes villous), flattened; bracts narrowly triangular, 1-5 mm long. Staminate flowers with brown stellatelepidote (sometimes villous), subglobose buds 1-2 mm diam., pedicels elongating from bud to anthesis, 1-6 mm long; sepals 5, pale green, shortly connate at base, lobes broadly triangularovate, 2.0-2.5 × 1.0- 1.5 mm, apex acute, inflexed at anthesis, abaxially stellate-lepidote, adaxially pilose, margins densely ciliate; petals 5, white, elliptic-spatulate, c. 2.5 × 0.8 mm, recurved at anthesis, abaxially stellate-lepidote and papillate, adaxially pilose, margins densely ciliate; disc glands/nectaries 5, opposite the sepals, sessile, ellipsoidal with an apical depression, 0.3-0.5 × 0.3-0.4 mm, pale yellow; stamens 10-17, white, filaments 1.5-2.6 mm long, ciliate, anthers elliptic, 0.5-0.9 × 0.4-0.7 mm; receptacle pilose. Pistillate flowers with stellatelepidote (sometimes villous) buds 1-2 mm diam., pedicels 1-4 mm long; sepals 5, elliptic, spreading at anthesis, 2-9.5 × 0.5-2.5 mm, apex acute, abaxially and adaxially sparsely stellate-lepidote, pale green, persistent in fruit; petals absent/ reduced; disc glands/nectaries 5, opposite the sepals, sessile, ellipsoidal, 0.4-0.7 × 0.3-0.5 mm, pale yellow; glandular filaments (petals?) alternating with the sepals, 0.7-2.0 mm long, ciliate; ovary densely stellate-pubescent (sometimes villous), subglobose, 1-2 mm diam., styles 3, 2.0- 3.5 mm long, each branch flattened and twice (rarely thrice) bifurcate for a total of 12 stigmatic tips, spreading, recurved at the apices, adaxially glabrous, abaxially sparsely stellate-pubescent, white, turning brown, persistent. Capsules c. 6-8 × 6-8 mm, smooth, brown, stellate-pubescent, exocarp not separating, endocarp woody, 0.2-0.4 mm thick; columella 4-5 mm long, cornute, capitate. Seeds ± compressed-ellipsoid, 3.5-4.3 × 2.7-3.1 mm; testa glossy, granulate, brown; caruncle narrowly reniform, c. 0.6 × 0.5 mm.

Distribution, habitat, and ecology. – Croton chapelieri is known from coastal Antsiranana, Fianarantsoa, Toamasina, and Toliara Provinces. It is sometimes locally frequent in littoral forest and scrub, mostly on white sands, from sea level to 40 m elevation ( Fig. 1 , 2 A-B).

Phenology. – Croton chapelieri appears to be aseasonal and flowers throughout the year.

Vernacular names. – Croton chapelieri has numerous recorded common names, which include: Fotsiavadika” (Jacquemin 1267), “Hazomanitra” (Louvel 217), “Sagnira” (Ludovic 1660), “Sarihafotra vavy” (Randrianaivo et al. 1976), “Sily” (Service Forestier 7289), “Tsinjeny” (Rabevohitra 2024) and “Tsivoanjo” (Hoffmann 194). They probably reflect both the morphological variation of the species and its widespread distribution that spans numerous different dialects of the Malagasy language.

Conservation status. – Croton chapelieri can be locally abundant, but its sandy littoral habitat is very restricted, and it is known so far from seven sites, three in Toliara, one in Antsiranana, one in Fianarantsoa and two in Toamasina provinces. We therefore recommend that it be assessed as “Near Threatened” [NT] following the IUCN Red List Categories and Criteria (IUCN, 2012).

Notes. – Although Leandri (1939) recognized C. chapelieri and even named his “Groupe Chapelieri” after it, he characterized the species as being “incomplètement connue.” This was presumably due to the poor condition of the type, which consists of a leafy branch with only the naked axis of one inflorescence [no flowers remain, although Baillon (1861) did describe them]. Also, there was no collecting location given. However, we know from Dorr (1997) that Chapelier (1779-1806) spent most of his time in Madagascar living near Foulpointe north of Tamatave, and it is quite likely that this is the area where the type of C. chapelieri came from. In the same treatise by Leandri (1939), he described C. louvelii as part of Groupe Chapelieri and recognized that both it and C. chapelieri have the same distinctive foliaceous pistillate calyces. His key simply separated C. louvelii from C. chapelieri as having “parties jeunes non hirsutes” vs. “parties jeunes un peu hirsutes.” The type locality of C. louvelii is the littoral forest of Tampina, which is farther south of Foulpointe in Toamasina Province. Comparing the two types, they are a very good match, and there are some trichomes on the young growth of C. louvelii that are similar to those on the type of C. chapelieri . These similarities are the justification for our decision to synonymize C. louvelii . Also, because of the lack of flowers on the single type specimen of C. chapelieri , we designate here an epitype from a recent collection (van Ee et al. 925) for which multiple duplicates, photos of live material, and DNA sequence data are available.

Leandri (1973) described the first of a series of taxa from the southeastern coast of Madagascar that are also treated here as synonyms of C. chapelieri . His C. aymoninorum Leandri came from the littoral forest of Mandena, along the coast north of Fort Dauphin. Instead of assigning it to one of the groups that he recognized in his earlier treatise (Leandri, 1939), he instead treated C. aymoninorum as part of a bewilderingly diverse array of species whose only character in common was that of their contracted inflorescences. Largely for that reason, we believe, its affinities to C. chapelieri went unnoticed, and later Radcliffe-Smith (2016) described C. daphniphyllum from the same forest that C. aymoninorum came from. Mandena is a relatively small area of sandy littoral forest that has been extensively collected by botanists over many decades, including ourselves, and we are quite confident that only three species of Croton occur there – C. chapelieri , C. cassinoides , and C. trichotomus .

Croton chapelieri is morphologically quite variable, particularly in leaf shape and pubescence. The leaves are typically elliptic but vary from lanceolate to obovate. Similarly, the apex can vary from acuminate to rounded, the base can be cuneate or rounded, and the margin can be entire or serrate towards the apex. Extensive collections and our own field studies from coastal areas of southeastern Toliara Province (Mandena, Petriky, and Sainte Luce) show that the types of both C. aymoninorum and C. daphniphyllum correspond to a locally common species found in sandy, littoral forests to the west and north of Fort Dauphin, in the Mahabo area of Fianarantsoa Province, and then in Toamasina Province farther north. In the Sainte Luce and Petriky areas of southeastern Toliara Province, besides the more typical stellate-lepidote form, there are populations in which the shoots, leaves, and inflorescences are villous due to the presence of a porrect central radius to the stellatelepidote trichomes ( Fig. 2C ). These forms correspond to what Radcliffe-Smith (2016) described as C. chapelieri var. hirsutus Radcl. -Sm. (from the Petriky forest) and C. rhododendroides Radcl. -Sm. (from the Sainte Luce forests), both of which are included here in synonymy as well. Finally, Radcliffe-Smith (2016) described C. daphniphylloides Radcl. -Sm., differing only slightly from his C. daphniphyllum and whose type comes from Ambila-Lemaitso, which is very close to the Tampina, the type locality of C. louvelii . The other paratype of C. daphniphylloides is from Tampolo, farther north in Toamasina Province and presumably close to the type locality of C. chapelieri itself.

The name C. chapelieri var. longepetiolata Radcl. -Sm. is based on a single specimen (Malcomber et al. 2511) from 500-750 m elevation in Zahamena National Park in Toamasina Province. It appears to be a fairly typical specimen of C. submetallicus Baill.

Beyond the specimens cited below, there are many more specimens of C. chapelieri that we have identified, particularly from the well-collected forests of Petriky, Mandena and Sainte Luce in Toliara Province and in the Mahabo Reserve of Fianarantsoa Province. These have all been entered into the Madagascar Catalogue (2016) with our determination and can be found in the specimen list under Croton chapelieri .

Selected additional specimens examined. – Madagascar. Prov. Antsiranana: Antalaha-CR Vinanivao, Cap Masoala, PD3 Beankora , 15°57’S 50°13’E, 10 m, 23.IX.2003, Callmander & Bohnenstegel SW 685 ( G). Prov. Fianarantsoa: Atsimo-Atsinanana Region, Farafangana District , Réserve Spéciale de Manombo , Agnalazaha Forest , 23°04’53”S 47°45’25”E, 25.X.2000, Hoffmann 295 ( K, MO, P, TAN); Mahabo-Mananivo, Mahabo , 23°10’36”S 47°42’01”E, 3.XI.2001, McPherson & Rabenantoandro 18310 ( K, MO, P, TEF); Farafangana, 27.VII.1955, Service des Eaux et Forêts 13969 ( K, P); Mitsevo-Farafangana , [23°00’S 47°45’E], 23.VI.1952, Service des Eaux et Forêts 7289 ( P, TEF); Mahabo Reserve, 23°10’41”S 47°42’07”E, 0-50 m, 11.XI.2009, van Ee et al. 1181 ( MICH, MO, TAN). Prov. Toamasina: Analanjirofo Region, Fenerive Est District , Ampasina , Tanambao-Tampolo , Station forestière de Tampolo , 17°16’S 49°25’E, 0-10 m, 5-7.IV.1997, Birkinshaw et al.381 ( MO); Atsinanana Region, Brickaville District , Ambinaninony , Andranokoditra , Vohibola forest , 18°33’34”S 49°15’01”E, 5 m, 12.II.2003, Lowry 6081 ( MO). Prov. Toliara: Anosy Region, Toalanaro District , Mandena forest , 20.II.1972, Debray 1759 ( P); Nord Fort-Dauphin, Sud Massif Tsingafiafy , 2.III.1973, Debray 1997 ( K, P); Mandena, 0-10 m, 17.IV.1989, Dumetz et al. 654 ( MO, P, TAN, TEF); [Mahatalaky], Sainte Luce forest , 24°47’S 47°10’E, 0-10 m, 21.X.1989, Dumetz et al. 774 ( MO, P, TAN, TEF); Sainte Luce , 24°46’42”S 47°10’15”E, 0 m, 13.X.2000, Hoffmann et al. 194 ( K, P); Forêt IIe d’Esetra entre la scierie et la R.N.12 a S/P Fort-Dauphin, 11.XII.1972, Jacquemin 1185 ( K, P); Ambandrika, Etazo forest , 24°49’00”S 47°07’43”E, 16 m, 9.IX.2012, Ludovic 1660 ( MO, TAN); Mahatatalaky, Ebakika , Magnindriavia forest , 24°45’50”S 47°08’35”E, 22 m, 10.IX.2012, Ludovic 1710 ( MO, P, TAN); Mandena, 24°57’S 47°02’E, 10 m, 17.X.1989, Rabevohitra 2024 ( MO, P, TAN, TEF); ibid. loc., Rabevohitra 2028 ( MO, TEF); Ampasy Nahampoa, Ambavarano forest , 24°57’28”S 47°03’16”E, 6 m, 8.XII.2006, Ramison 123 ( MICH, MO, P, TAN); Belavenoko forest, 24°49’07”S 47°07’52”E, 17 m, 25.XI.2011, Ratovoson 1781 ( MICH, MO, P, TAN); Tsiaronampasy, Antongoranambo , 24°48’54”S 47°08’32”E, 30 m, 22.X.2012, Ratovoson 1998 ( MICH, MO, P, TAN); Mandena, 24°57’10”S 47°00’10”E, 12-25 m, 31.VII.2015, van Ee et al. 2135 ( MICH, MO, TAN).

Figures

Fig. 1. – Geographic distribution of Croton chapelieri Baill. (stars) and C. vatomandrensis Leandri (circles), mapped on the bioclimatic zones of Madagascar (after CORNET, 1974; see SCHATZ, 2000).

Fig. 2. – Croton chapelieri Baill. A. Typical littoral habit at Mahabo, Atsimo-Atsinanana Region, Fianarantsoa Province; B. Shrubs growing

Fig. 4. – Croton chapelieri Baill. (A-F) and C. vatomandrensis Leandri (G-L). A-C. Staminate flower: side view (A), top view (B) and top view with stamens removed to show the five nectaries (C). D-F. Pistillate flower: side view (D), top view (E), and top view with ovary removed to show the five nectaries (F). G-I. Staminate flower: side view (G), top view (H), and top view with stamens removed to show the five nectaries (I). J-L. Pistillate flower: side view (J), top view (K), and top view with ovary removed to show the five nectaries (L). [A-F: van Ee et al. 1181; G-L: van Ee et al. 1194]