Croton ferricretus Kainul., B. W. van Ee & P. E. Berry 2016, spec. nova
Creators: name: Kainulainen, Kent
name: Ee, Benjamin van
name: Antilahimena, Patrice
name: Razafindraibe, Hanta
name: Berry, Paul E.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Malpighiales
Euphorbiaceae
Croton
Croton ferricretus

description: Croton ferricretus Kainul., B.W. van Ee & P.E. Berry, spec. nova (Fig. 1A, 5 H-M, 7A-B, 8).
Typus: MADAGASCAR. Prov. Toamasina: Alaotra- Mangoro Region, Moramanga Distr., Andasibe, Berano, Ambatovy mine concession, on “cuirasse” between the workers houses and the Ambatovy supply road, within sight of the Ambatovy office building, 18°51’02”S 48°18’29”E, 1142 m, 21.III.2016, van Ee, Antilahimena, Kainulainen & Berry 2436 (holo- MICH [MICH1513194]!; iso-: G!, K!, MAPR!, MO!, P!, TAN!).
Croton ferricretus Kainul., B.W. van Ee & P.E. Berry is similar to C. antanosiensis Leandri in its medium-sized, lepidote leaves and elongate inflorescences, but differs from it in the more ferrugineous indumentum (vs. silvery), shorter petioles, and obloid (vs. globoid) capsules.
Shrubs 0.4-4 m tall, dichotomously branching, internodes sometimes contracted giving the appearance of whorled branches. Branches ± flattened on new growth and densely ferrugineous-lepidote, brown or gray, becoming terete and glabrous with age. Stipules linear-triangular, 0.5-1 mm. Leaves alternate along stem, subopposite or whorled at apex. Petioles 3-17(-28) mm, adaxially canaliculate, without any apparent glands. Leaf blades subcoriaceous, entire, elliptic, 18-85 × 9-28 mm, apex acute to shortly acuminate (rarely obtuse), base cuneate; adaxial surface glabrous, glossy, dark green when fresh (turning orange in old leaves) and drying gray-green; venation impressed, obscure, with 10-20 pairs of brochidodromus, ± penninerved secondary veins; abaxial surface densely silverylepidote and ferrugineous-punctate, the ferrugineous scales scattered among silvery ones, but more prevalent on the leaf veins; midrib prominent, ferrugineous-lepidote. Inflorescences racemose, 20-85 mm long, axillary or terminal, with mostly staminate flowers, usually with 1-2(-5) pistillate flowers at the base; axes densely ferrugineous-lepidote, flattened; bracts linear-lanceolate, 1-3 mm long. Staminate flowers with ferrugineous-lepidote, subglobose buds 1.5-2.5 mm in diam., pedicels elongating from bud to anthesis, 2-5 mm long; sepals 5, firm, connate about halfway from the base, lobes broadly triangular to ovate, 1.0-1.4 × 0.8-1.7 mm, apex acute, inflexed at anthesis, abaxially ferrugineous-lepidote, adaxially glabrous, pale green; petals 5, white, narrowly obovate-spatulate, 1.8-2.5 × 0.5-1.1 mm, recurved at anthesis, abaxially lepidote, adaxially ciliate, margins densely ciliate; disc glands/nectaries 5, opposite the sepals, sessile, ellipsoid with an apical depression, 0.6-0.8 × 0.5-0.7 mm, yellow; stamens 14-19, white to pale yellow, filaments 1-2 mm long, ciliate, anthers elliptic, 0.5- 0.7 mm long; receptacle pilose. Pistillate flowers with ferrugineous-lepidote, elliptic buds 2.8-3.0 × 1.7-2.5 mm, pedicels 1-8 mm long; sepals 5, firm, narrowly triangular, ascending at anthesis, 1.8-5.3 × 0.5-1.3 mm, apex acute, shortly connate at base, abaxially ferrugineous-lepidote, adaxially glabrous, pale green, persistent in fruit; petals absent/reduced; disc glands/ nectaries 5, opposite the sepals, sessile, pentagonal, 0.8-1.0 × 0.6-0.8 mm, yellow; ovary obloid, 2.0- 2.5 mm diam., lepidote, styles 3, c. 3 mm long, each bifurcating twice (or ultimately thrice), spreading, recurved at the apices, abaxially ferrugineous-lepidote, adaxially glabrous but with yellowish pilose trichomes at the base, white, turning brown, persistent. Capsules 4.5-9.0 × 3.5-6.0 mm, smooth, gray-green, lepidote, exocarp not separating, endocarp woody, c. 0.2 mm thick; columella 4-6 mm long, cornute, capitate. Seeds ± compressed-ellipsoid, c. 5 × 3 × 2 mm; testa glossy, rugulose, punctate, dark brown; caruncle reniform c. 1.3 × 0.5 mm.
Etymology. – The specific epithet refers to the ultramafic ferricrete soils to which this species is restricted.
Vernacular names. – “Fotsiavadika”, “Lazalaza”.
Phenology. – Flowering and fruiting specimens have been collected from May through March, indicating that Croton ferricretus is quite aseasonal in its phenology.
Distribution, habitat and ecology. – Croton ferricretus is so far only known from the Ambatovy-Analamay forest in Madagascar’s Moramanga Distr., occurring at 1000-1150 m altitude on ultramafic ferricrete soils (Fig. 1A, 8A). It is a common and sometimes dominant component of the scrublands found on the most extreme rock-like crusts, and it also occurs in adjacent evergreen forests with better-developed soils. When growing on bare ferricrete (“cuirasse”), C. ferricretus does not occur with other species of Croton, but in forested areas it can be found growing alongside C. lichenisilvae Leandri, C. macrobuxus Baill., C. nitidulus Baker, C. submetallicus Baill., or C. droguetioides.
Notes. – Croton ferricretus was recognized in the inventory of the Ambatovy-Analamay forest by PHILLIPSON et al. (2010) under the working name “ Croton lepidotoides ” (ined. by the late Radcliffe-Smith), and considered a species of concern (SOC2, i.e., found only in the area of the mining footprint and the surrounding conservation zone). This is a very distinctive species among Malagasy Crotons that have small- to medium-small leaves with coppery-lepidote indumentum (Fig. 8 B-C). Other species that have these characteristics tend to have glomerulate inflorescences in the leaf axils, such as C. jennyanus Gris ex Baill. and C. hypochalibaeus Baill., rather than racemose inflorescences (Fig. 8 D-F). It resembles C. antanosiensis Leandri from southeastern Madagascar, but differs in its much more coppery-lepidote indumentum, shorter petioles, and more obloid capsules (Fig. 7A).
Since this is a locally common species that is capable of growing on bare, ferricrete substrates, we believe that it may be an excellent candidate for revegetation efforts once the mining operations at Ambatovy-Analamay have ceased. Its shrubby habit would enable it to reproduce more quickly than tree species, and it could help stabilize slopes in previously mined areas.
Paratypi. – MADAGASCAR. Prov. Toamasina: Alaotra-Mangoro Region, Moramanga distr., Ambatovy-Analamay forest, 18°50’47”S 48°18’28”E, 1137 m, 9.II.2005, Antilahimena et al. 3323 (G, K, MO, P, TAN); ibid.loc., 18°51’27”S 48°19’07”E, 1113 m, 30.IX.2005, Antilahimena & Edmond 3862 (MICH, MO, P, TAN); ibid.loc., Antilahimena & Edmond 3863 (MICH, MO, P, TAN); ibid.loc., 18°48’28”S 48°20’11”E, 1049 m, 2.XII.2005, Antilahimena et al. 4324 (G, MO, P, TAN); ibid.loc., 18°48’29”S 48°20’21”E, 1104 m, 21.XII.2005, Antilahimena 4513 (G, K, MO, P, TAN); ibid.loc., 18°51’01”S 48°18’30”E, 1119 m, 6.III.2008, Antilahimena et al. 6140 (MICH, MO, P, TAN), 18°51’01”S 48°18’30”E, 1119 m, 6.V.2008, Antilahimena et al. 6144 (MICH, MO, P, TAN); ibid.loc., 18°51’11”S 48°19’05”E, 1095 m, 27.X.2008, Antilahimena et al. 6765 (MO, TAN); ibid.loc., 18°51’00”S 48°18’29”E, 1114 m, 12.XI.2009, Antilahimena & Edmond 7175 (MICH, MO, P, TAN); ibid. loc., 18°48’34”S 48°19’08”E, 1080 m, 5.X.2007, Bernard & Phillipson 596 (MICH, MO, P, TAN); ibid.loc., 18°48’32”S 48°20’42”E, 11.X.2007, Bernard & Phillipson 619 (MICH, MO, P, TAN); ibid.loc., 18°51’14”S 48°18’56”E, 1114 m, 18.I.2010, Bernard et al. 1532 (MO, P, TAN); ibid.loc., 18°48’12”S 48°21’56”E, 995 m, 3.VI.2007, Miandrimanana et al. 201 (MO, P, TAN); 22.II.1965, Peltier & Peltier 5169 (P); ibid.loc., Peltier & Peltier 5994 (P); 18°48’31”S 48°20’39”E, 1115 m, 6.X.2007, Phillipson et al. 6034 (MICH, MO, TAN); ibid.loc., 18°51’08”S 48°18’40”E, 1121 m, 30.I.1997, Rakotomalaza et al. 1024 (MO, P, TAN); ibid.loc., 18°48’28”S 48°20’04”E, 1083 m, 4.IV.2005, Rakotovao & Edmond 1801 (MO, TAN); 18°48’22”S 48°20’13”E, 1075 m, 3.VIII.2005, Rakotovao et al. 1961 (MICH, MO, P, TAN); 18°48’29”S 48°19’17”E, 1122 m, 16.I.2005, Ranaivojaona et al. 1101 (MICH, MO, P, TAN); ibid.loc., 18°50’04”S 48°17’46”E, 1107 m, 15.II.2005, Razanatsoa et al. 113 (MICH, MO, P, TAN); ibid.loc., 18°51’06”S 48°18’40”E, 1114 m, 18.II.2005, Razanatsoa et al. 187 (G, MO, P, TAN); ibid.loc., 18°51’24”S 48°19’02”E, 1114 m, 26.IX.2005, Razanatsoa et al. 401 (G, MO, P, TAN); 18°49’20”S 48°19’40”E, 1132 m, 20.X.2005, Razanatsoa & Razafindasy 548 (MO, P, TAN); ibid.loc., 4.III.1987, Service Forestier 31265 (TEF); ibid.loc., 18°48’55”S 48°19’28”E, 1114 m, 21.III.2016, van Ee et al. 2437C (MICH, MO, P, TAN); ibid.loc., van Ee et al. 2438 (MICH, MO, P, TAN); ibid.loc., 18°48’28”S 48°20’11”E, 1050 m, 22.III.2016, v an Ee et al. 2454 (MICH, MO, P, TAN); ibid.loc., van Ee et al. 2455 (MICH, MO, P, TAN).
description: Published as part of Kainulainen, Kent, Ee, Benjamin van, Antilahimena, Patrice, Razafindraibe, Hanta & Berry, Paul E., 2016, New species and species reports of Croton L. (Euphorbiaceae) from the eastern forest corridor of Madagascar, pp. 327-356 in Candollea 71 (2) on pages 337-338, DOI: 10.15553/c2016v712a17, http://zenodo.org/record/5721805