Croton mayottae P.E. Berry & Kainul.

Kainulainen, Kent, Ee, Benjamin van, Razafindraibe, Hanta & Berry, Paul E., 2017, A revision of the Adenophorus Group and other glandular-leaved species of Croton (Euphorbiaceae) from northern Madagascar and Mayotte, including three new species, Candollea 72 (2), pp. 371-402: 392-401

publication ID

http://doi.org/ 10.15553/c2017v722a15

persistent identifier

http://treatment.plazi.org/id/543287AA-CB30-FFB4-FCF4-FE32FC7D56D9

treatment provided by

Carolina

scientific name

Croton mayottae P.E. Berry & Kainul.
status

spec. nova

Croton mayottae P.E. Berry & Kainul.   , spec. nova ( Fig. 2E View Fig , 9).

Typus: FRANCE. Dept. Mayotte: Grande-Terre, Chiconi, village, 16.I.2001, Barthelat, M’Changama & Sifary 225 (holo-: P [P00229211]!; iso-: G [G00341697]!, K!, MAO, MO!).

= Croton regeneratrix var. mayottensis Radcl.   -Sm., Gen. Croton Madag. Comoro   202. 2016. Typus: FRANCE. Dept. Mayotte: Rassi Maoussi , 30 m, 24.IV.1997, Pascal 915 (holo-: K!; iso-: BR, G [ G00341698]!, MO!, P [P00144592]!, WAG), syn. nov.

Croton mayottae P.E. Berry & Kainul.   is similar to C. loucoubensis Baill.   but differs in its cordate (vs rounded) leaf bases, serrulate stipules (vs fimbriate), stellate-pubescent (vs bristly hirsute) ovary, and smaller and thinner-walled capsules (c. 7 mm diam. with endocarp c. 0.4 mm thick vs ≥ 10 mm diam. with endocarp c. 2 mm thick).

Shrubs 2-3 m tall, dichotomously branching. Branches terete, with a scurfy indument of short, tan-colored, fasciculatestellate trichomes. Older stems smooth, matte tan to pale gray, glabrescent, with lighter-colored oval lenticels, with reddish latex. Stipules 10-20 mm long, narrowly lanceolate, finely serrate along the margins, with an aristate tip, caducous. Leaves opposite, apparently deciduous; leaf scars conspicuous and drying much darker than the adjacent stem tissue. Petioles 1.5-6 cm long, densely scurfy-pubescent like the young stems, with a pair of subsessile, concave, discoid glands (0.4-0.6 mm diam.) on the lower side of the base of the lamina. Leaf blades firmly papyraceous, finely denticulate, ovate, 5-10 × 3-6 cm, apex acuminate, base cordate; both sides covered with a moderately dense cover of stellate trichomes (these not overlapping, so leaf surface can be seen underneath), green when fresh and drying matte pale green; venation 5- or 7-palmate at the base, with 2-6 pairs of penninerved secondary veins from around the middle of the blade, veins prominent and lighter-colored on abaxial side, usually with some acetabuliform glands in the axils of some of the secondary and tertiary veins ( Fig. 9B). Inflorescences terminal, raceme-like thyrses, 6-10 cm long, with c. 4-12 pistillate flowers in the basal part and numerous staminate flowers distally, axes densely tan-scurfy with tightly fasciculate trichomes; bracts triangular, 2-4 × 1-2 mm, semipersistent. Staminate flowers with densely scurfy, subglobose buds 1.5- 2.5 mm diam., pedicels 2-7 mm long; sepals 5, shortly connate at base, lobes broadly triangular-ovate, 2-2.5 × 2.2-3 mm, apex

[A, D-E: van Ee et al. 2313; B-C: van Ee et al. 1089] [Photos: A-B, D-E: P. Berry; C: B. van Ee]

acute, inflexed at anthesis, abaxially stellate-pubescent, adaxially stellate towards apex, margins ciliate; petals 5, elliptic to spatulate, 2-2.8 × 1-1.7 mm, recurved at anthesis, abaxially stellate and papillose, adaxially glabrous, margins densely ciliate; disc glands 5, opposite the sepals, sessile, ellipsoidal with an apical depression, c. 0.5 × 0.5 mm, yellow; stamens c. 14, white, filaments 2-3 mm long, glabrous, anthers broadly elliptic, c. 1 × 0.9 mm; receptacle pilose. Pistillate flowers with densely scurfy-stellate buds 2-2.5 mm diam., pedicels 3-6 mm long; sepals 5, triangular, 2-3.5 × 1.5-2.5 mm, apex acute, densely tan-scurfy abaxially and adaxially stellate, petals absent or reduced to short filaments ca 1.5 mm long; disc glands 5, opposite the sepals, sessile, ellipsoidal, c. 0.4 × 0.8 mm, yellow; ovary globoid, 2.7-4 mm diam., densely covered by compact, golden-stellate trichomes; styles 3, 1.5-3.3 mm long, each branch flattened and twice bifurcate, spreading, abaxially stellate-pubescent, adaxially glabrous, persistent. Capsules c. 6 mm long, light brown, puberulent, the endocarp woody, c. 0.4 mm thick; columella 4.5-5 mm long, the apex cornute with partially recurved fibers. Seeds broadly compressed-ellipsoid, c. 4.7 × 3.8 × 2.7 mm; testa matte, light brown, slightly rugulose; caruncle shield-shaped, c. 1 × 1.5 mm.

Etymology. – Named after the island of Mayotte, in the

Comoros Archipelago, where this species is endemic.

Phenology. – Specimens in bud have been collected in March and April, flowering specimens in October–November and in January, and a specimen in fruit in November.

Distribution, habitat and ecology. – Croton mayottae   occurs in seasonally dry forest, mainly near the coastline, on the Grande- Terre island of Mayotte at elevations from sea level to 170 m ( Fig. 2E View Fig ).

Conservation assessment. – Since the species in endemic to the island of Mayotte and restricted there to coastal forest remnants in only four localities, we consider it to be “Endangered” [EN B1ab(iii)] according to IUCN Red List Categories and Criteria ( IUCN, 2012).

Vernacular names. – “M’Houvé” (Soumille 992), “Mouhouve” (Hoffman & Ranmanana 363), “Muhuve [in Shibushi, Shimahorais]” (Barthelat & Rolland 1324), “Sary lazalaza” (Barthelat & Rolland 1324).

Notes. – RADCLIFFE-SMITH (2016) based his description of C. regeneratrix var. mayottensis   on a single collection in early bud, and he failed to note that it had opposite leaves and glands on the undersides of the leaves, whereas C. regeneratrix   has alternate leaves that lack laminar glands. He treated another specimen of C. mayottae   (Pascal 724) as C. adenophorus   . Rather than making a combination based on the type of Radclife- Smith’s variety, we prefer our choice of type for C. mayottae   , which has open pistillate and staminate flowers and is much more diagnostic for the species. The other native Croton species   on Mayotte include C. humblotii Baill.   , which also occurs on the three islands of the Union of the Comoros; C. bifurcatus Baill.   , and C. emeliae Baill.   , which like C. mayottae   are found only on Mayotte; and finally C. adenophorus   , which occurs mainly on mainland Madagascar in Antsiranana Province.

Additional specimens examined. – FRANCE. Dept. Mayotte: Saziley , 21.III.2004, Barthelat & Rolland 1324 ( G, K, MAO, MO, P); Combani , Parcelle de Bakar , 11.IV.2001, Hladik 6534 (P); Saziley, 12.IV.2001, Hladik 6558 (P); ibid loc., 12°58’S 45°11’E, 170 m, 11.XI.2002, Hoffman & Ralimanana 363 ( G, K, MAO, MO, P, TAN); ibid loc., 80 m, 17.X.1996, Pascal 724 ( MO, P); Sazilé Bé, 12°58’39”S 45°12’01”E, 100- 150 m, 11.IV.1999, Pignal 1111 ( G, K, P); Saziley, 0 m, 14.XI.1997, Soumille 992 ( G, K, MO, P, WAG) GoogleMaps   .

Croton orangeae Kainul. & P.E. Berry   , spec. nova ( Fig. 1F, 2D View Fig , 4 View Fig K-L, 10).

Typus: MADAGASCAR. Prov   . Antsiranana: Diana Reg., Ramena , Ankorikakely, Baie des Sakalava, 12°16’40”S 49°23’01”E, 25 m, 9.XII.2004, Razafitsalama et al. 692 (holo-: MICH [ MICH1517188]!; iso-: CNARP, MO!, P [P05484901]!, TAN) GoogleMaps   .

Croton orangeae Kainul. & P.E. Berry   is similar to C. adenophorus Baill.   in its denticulate, cordate leaves and glabrous stems, but differs in its stipules that are awn-shaped (vs foliaceous), its mature leaves that are scabrously stellate-pubescent (vs subglabrous), and the bark of the branches matte and tan to gray (vs ± glossy and reddish brown) and soon turning flaky (vs smooth).

Shrubs 1-4 m tall, dichotomously branching, internodes sometimes so short as to give the appearance of whorled branches. Branches flattened on new growth but becoming terete with age, pale green and sparsely covered with whitish stellate indument, soon turning tan to gray, glabrous, matte. Bark flaky, gray to brown ( Fig. 10B View Fig ). Stipules 5-10 mm long, awn-shaped, early caducous. Leaves opposite, deciduous. Petioles 0.5-10 cm long, adaxially canaliculate, stellate-pubescent, usually with a pair of subsessile, concave, discoid glands 0.4-0.6 mm diam. at the junction with the lamina. Leaf blades chartaceous, (subentire) dentate to denticulate, ovate, 2.2-14.0 × 2.5-14 cm, apex (acute) acuminate, base (truncate) cordate; both sides with a persistent, scabrous stellate indument, green when fresh, drying matte pale green to brown; venation evident, with 6-10 pairs of brochidodromus, ± penninerved secondary veins (the lowermost pairs congested and appearing palmate), and cross-venulate tertiary venation; venation prominent, sometimes with glands in some of the axils of the secondary veins on the lower surface ( Fig. 1F), but absent in most leaves. Inflorescences terminal, racemelike thryses 1-6.5 cm long, bisexual with pistillate flowers towards the base and staminate flowers towards the distal end, axes stellate-pubescent, flattened; bracts narrowly triangular, c. 2.5 mm long, caducous. Staminate flowers with stellate-pubescent, subglobose buds, c. 1.8 mm diam., pedicels elongating from bud to anthesis, 1-5 mm long; sepals 5, pale green, shortly connate at base, lobes broadly triangular-ovate, 2-2.5 × 1.5-1.8 mm, apex acute, inflexed at anthesis, abaxially stellate-pubescent, adaxially glabrous, margins ciliate; petals 5, elliptic to spatulate, 1.5-2.5 × 0.7-0.9 mm, recurved at anthesis, abaxially glabrous and papillose, adaxially ciliate towards apex, margins densely ciliate; disc glands 5, opposite the sepals, sessile, ellipsoidal, c. 0.4 × 0.6 mm, yellow; stamens 13-21, white, filaments 1.5-2.5 mm long, ciliate, anthers broadly elliptic, c. 0.8 × 0.7 mm; receptacle pilose. Pistillate flowers with stellate-pubescent buds 2-2.5 mm diam., pedicels 1.5- 5.5 mm long; sepals 5, elliptic, not spreading at anthesis, 1.8-2.8 × 1-1.7 mm, apex acute, shortly connate at base, abaxially and adaxially stellate-pubescent, persistent in fruit; petals sometimes absent or reduced, when present 1.4-1.8 × 0.7-0.9 mm, spatulate, glabrous except for the ciliate margin, abaxially papillose; disc glands 5, opposite the sepals, sessile, ellipsoidal, 0.3 × 0.7 mm, yellow; ovary densely covered by ferrugineous to dark brown, stellate trichomes, globoid-ellipsoid, 2-3 mm diam., styles 3, c. 2 mm long, each branch flattened and twice bifurcate, spreading, recurved at the apices, abaxially stellate-pubescent, adaxially glabrous, persistent. Capsules broadly globoid, 5 × 6.5 mm, smooth, pale brown, covered with contrasting dark brown stellate trichomes ( Fig. 4K View Fig ), exocarp not separating, endocarp woody, c. 0.5 mm thick; columella 4-5 mm long, cornute, capitate. Seeds ± compressed-ellipsoid, c. 3.5 × 3 × 2 mm; testa matte, verrucose, pale brown; caruncle narrowly reniform c. 0.4 × 1 mm ( Fig. 4L View Fig ).

Etymology. – The epithet refers to the Orangea (Oronjia) Peninsula in Antsiranana Province, where the type was collected and the species is apparently restricted.

Phenology. – Only a few specimens are known, collected in bud in March, in flower in August-December, and in fruit in December.

Distribution, habitat and ecology. – This species is so far only known from the Orangea (Oronjia) Peninsula in northern Antsiranana Province where it grows in dry scrub vegetation and littoral forest on limestone and sand, from sea level to c. 50 m in elevation ( Fig. 2D View Fig ).

Conservation assessment. – Croton orangeae   is known only from the Orangea Peninsula. The deciduous forests of Orangea are currently threatened by deforestation despite their recent additon to Madagascar’s protected area network. Deforestation is mostly related to agricultural practices. Given this and the extent of occurrence is <5000 km 2, the new species is assigned as “Endangered” [EN B1 ab(iii)], according the IUCN Red List Categories and Criteria ( IUCN, 2012).

Notes. – Croton orangeae   is distinct for its glabrous, grayish branches with flaky bark, and dentate to denticulate leaves with a persistent, scabrous indument on both sides. In the shape of the leaves and in the pale brown capsules with white and contrasting brown stellate trichomes, it may appear similar to C. adenophorus   , but that species has a glossy reddish bark and subglabrous leaves, and also differ in its usually longer inflorescences (1.5-22 cm vs 1-6.5 cm in C. orangeae   ), and distinctly foliaceous stipules and calyces. No vernacular names have been noted for this species.

Additional specimens examined. – MADAGASCAR. Prov. Antsiranana: Diana Reg., Antsiranana Distr., Orangea , 25.XI.1970, Debray 1525-D (K, P)   ; ibid. loc., 12°14’20”S 49°21’49”E, 13 m, 29.VIII.2001, Rabenantoandro & Razanatsoa 579 ( MO, P) GoogleMaps   ; ibid. loc., 12°14’08.2”S 49°21’40.3”E, 50 m, 25.X.2009, van Ee et al. 1080 ( MICH) GoogleMaps   ; ibid. loc., 12°13’54”S 49°21’28”E, 19 m, 5.III.2016, van Ee et al. 2343 ( MICH, TAN) GoogleMaps   ; ibid. loc., 12°14’08”S 49°21’41”E, 30 m, 5.III.2016, van Ee et al. 2351 ( MICH, TAN) GoogleMaps   ; ibid. loc., 5.III.2016, van Ee et al. 2352 ( MICH, TAN) GoogleMaps   ; ibid. loc., 5.III.2016, van Ee et al. 2353 ( MICH, TAN) GoogleMaps   .

Croton sahafariensis Kainul. & P.E. Berry   , spec. nova ( Fig. 1G, 2D View Fig , 4 View Fig M-N, 11).

Typus: MADAGASCAR. Prov   . Antsiranana: Diana Reg., Sahafary forest in the Saharaina river basin, road off of RN 6 to the E   towards the “red tsingy”, 12°36’19”S 49°26’23”E, 250 m, 26.X.2009, van Ee et al. 1089 (holo-: MICH [ MICH1517187]!; iso-: P!, TAN) GoogleMaps   .

Croton sahafariensis Kainul. & P.E. Berry   is similar to C. tsiampiensis Leandri   , from which it differs in that the leaves are not markedly hirsute but instead have a whitish woolly pubescence on the abaxial side, and in having bracts which are usually extended well beyond the buds. In its opposite, woolly leaves and awn-like bracts C. sahafariensis   may also be superficially similar to C. danguyanus Leandri   , but that species lacks laminar glands and its pistillate flowers have an inflated, conduplicate calyx.

Shrubs 1.5-5 m tall, dichotomously branching, internodes sometimes so short as to give the appearance of whorled branches; in all parts covered in whitish or ferrugineous, stellate trichomes many of which have a bristly, porrect (to c. 2 mm) central radius. Branches flattened on new growth but becoming terete with age, pale grayish-green and hirsute with ferrugineous, stellate indument, soon turning a glabrous, matte gray to brown bark. Stipules 10-15 mm, lanceolate, entire, with marginal glands, caducous. Leaves deciduous, opposite. Petioles 1-10 cm, adaxially canaliculate, stellate-pubescent to markedly hirsute, usually with a pair of subsessile (stipe <1 mm), concave, discoid, yellow, glands (c. 0.5 in diam) by the base of the lamina. Leaf blades chartaceous, glandular denticulate, broadly ovate to subreniform, 2.4-15 × 2.3-11.5 cm, apex rounded, acute or shortly acuminate, base cordate; adaxial surface stellate-pubescent, pale green when fresh (turning orange in old leaves) and drying matte greenishbrown; venation evident, with 5-8 pairs of brochidodromus, ± penninerved secondary veins (the lowermost pairs congested and appearing palmate), and cross-venulate tertiary venation; abaxial surface light green, densely covered by ± woolly, whitish stellate-pubescent hairs with contrasting ferrugineous hairs scattered along the veins; venation prominent, with glands in some of the axils of the secondary veins ( Fig. 1G). Inflorescences terminal, spike-like thryses to 8 cm long, with pistillate flowers more prevalent toward the base and staminate flowers towards the distal end, axes densely ferrugineous stellate-pubescent, flattened; bracts narrowly triangular to lanceolate, ± inflected, 3-7 mm long. Staminate flowers with stellate-pubescent, subglobose buds 1.6-2.5 mm in diam., pedicels elongating from bud to anthesis, 1.5-2 mm long; sepals 5, whitish, shortly connate at base, lobes broadly triangular-ovate, 1.5-2 × 1-1.3 mm, apex acute, inflexed at anthesis, abaxially ferrugineous stellate-pubescent, adaxially glabrous, margins ciliate; petals 5, white, elliptic-spatulate, c. 2.6 × 1.4 mm, recurved at anthesis, abaxially papillose and densely stellate-pubescent, adaxially glabrous, margins densely ciliate; disc glands 5, opposite the sepals, sessile, ellipsoidal with an apical depression, c. 0.4 × 0.5 mm, yellow; stamens 14-15, white, filaments 2-3.7 mm long, glabrous, anthers broadly elliptic, c. 0.6 × 0.5 mm; receptacle pilose. Pistillate flowers with stellatepubescent buds, c. 1.5 mm in diam., subsessile; sepals 5, triangular-ovate, spreading at anthesis, c. 2.5 × 1.2 mm, apex acute, shortly connate at base, abaxially and adaxially stellatepubescent, greenish yellow, persistent in fruit; petals absent or vestigial; disc glands 5, opposite the sepals, sessile, ellipsoidal, c. 0.3 × 0.6 mm, pale yellow; glandular filaments sometimes alternating with the disc glands, 0.2-0.4 mm long; ovary globose, 2-2.5 mm in diameter, densely hirsute by whitish to pale brown, long-rayed stellate trichomes, styles 3, 1.5- 2.0 mm long, each branch flattened and 2-3(-4) times bifurcate, spreading, recurved at the apices, abaxially stellate-pubescent, adaxially glabrous, greenish white, turning brown, persistent. Capsules globoid, c. 6.5 mm in diam., smooth, brown, covered with brown stellate trichomes ( Fig. 4M View Fig ), exocarp not separating, endocarp woody, c. 0.4 mm thick; columella 4.5-7 mm long, cornute, capitate. Seeds ± compressed-ellipsoid, 4-5.8 × 3-4.1 × 2.5 mm ( Fig. 4N View Fig ); testa glossy, verrucose, brown; caruncle narrowly reniform c. 0.6 × 1.4 mm.

Etymology. – The epithet refers to the Sahafary forest in

Antsiranana Province, where the type was collected   .

Phenology. – Only a few specimens are known, collected in flower in October-November and January-March, and in fruit in October, January, and March.

Distribution, habitat and ecology. – Croton sahafariensis   occurs in deciduous forests in northern Antsiranana Province, on sandy or lateritic soils, at 150-300 m elevation ( Fig. 2D View Fig ).

Conservation assessment. – Croton sahafariensis   is known only from small and fragmented populations at just four localities of threatened deciduous forests in Antsiranana Province (Ambohitsitondroina, Montagne des Français, Sahafary, and Tsaramborona). With an extent of occurrence <5,000 km 2 and an area of occupancy of <500 km 2 and with each of the four known localities representing separate threat locations, we assign this species as “Endangered” [EN B1ab(iii)+B2ab(iii)] according the IUCN Red List Categories and Criteria ( IUCN, 2012).

Notes. – This species can be recognized by its whitish, ± woolly pubescence on the abaxial side of the leaves with contrasting ferrugineous trichomes prevalent along the veins, and in its awn-like bracts that usually extend well beyond the buds ( Fig. 1G, 11). In these characteristics it may be superficially similar to C. danguyanus Leandri   , however, that species has pistillate flowers with large, inflated, and conduplicate sepals, and the leaves lacks laminar glands; also, C. danguyanus   is not part of the Adenophorus Group. Gautier & Chatelain 4876 is tentatively included here, but the leaves of this specimen are very young and small. The sterile specimen van Ee et al. 2363 from Montagne des Français probably also belong here. The leaves of this specimen are not woolly, but since it grew in the understory it is possible this represents phenotypical variation. There are currently no vernacular names recorded for this species.

Additional specimens examined. – MADAGASCAR. Prov. Antsiranana: SAVA Reg., Vohemar Distr., Daraina , Tsaramborona forest , 12°57’47”S 49°37’12”E, 150 m, 20.XI.2006, Gautier & Chatelain 4876 ( G, MICH, P) GoogleMaps   ; Daraina, Ambohitsitondroina forest , 13°07’44”S 49°27’29”E, 286 m, 6. I.2006, Nusbaumer & Ranirison 1862 ( G, MO) GoogleMaps   ; ibid loc., 13°07’56”S 49°28’21”E, 210 m, 12. I.2006, Ranirison & Nusbaumer 1077 ( G, K, P) GoogleMaps   ; Diana Reg., Antsiranana II Distr., Sadjoavato, Saharenana , Andranomadiro forest SW of Sahafary, 12°36’18”S 49°26’35”E, 300 m, 14.II.2005, Schatz et al. 4269 ( CNARP, G, MO, P, TAN) GoogleMaps   ; ibid loc., 12°36’20”S 49°26’22”E, 258 m, 2.III.2016, van Ee et al. 2312 ( MICH, TAN) GoogleMaps   ; ibid loc., van Ee et al. 2313 ( MICH, TAN) GoogleMaps   ; ibid loc., van Ee et al. 2314 ( MICH, TAN) GoogleMaps   ; Montagne des Français , 12°19’25”S 49°20’10”E, 235 m, 5.III.2016, van Ee et al. 2363 ( MICH, TAN) GoogleMaps   .

[A, C, D: van Ee et al. 2329; B, E-F: van Ee et al. 1118; G-H: van Ee et al. 1129] [Photos: A, C: K. Kainulainen; B, D-H: P. Berry]

Croton scoriarum Leandri   in Adansonia, sér. 2, 12: 68. 1972. ( Fig. 1H, 2C View Fig , 12 View Fig ).

Lectotypus (designated here): MADAGASCAR. Prov. Mahajanga: Centre, au lieu dit Analankeboka, à l’W de Bealanana, 20.XI.1966, Service Forestier 27107 (P [P00706283]!; isolecto-: K [K000895678]!, P [P00706284]!, TEF [TEF000183]!)   .

= Croton bathianus var. ambatondrazakae Radcl.   -Sm., Gen. Croton Madag. Comoro   114. 2016. Typus: MADAGASCAR. Prov. Toamasina: Alaotra-Mangoro Reg., Ambatondrazaka Distr., Menaloha , 900 m, XI.1937, Cours 587 (holo-: P [P00127483]!), syn. nov.

Shrubs or trees 1.5-8 m tall, dichotomously branching. Branches flattened on new growth but becoming terete with age, initially green with a farinose cover of whitish, stellate trichomes, but soon turning reddish-brown and glabrous. Mature bark papery and flaky. Stipules 2-7 × 1-1.5 mm, lanceolate, with marginal glands, early caducous. Leaves opposite, deciduous. Petioles 1-10 cm long, adaxially canaliculate, stellate-pubescent at first, soon glabrous, usually with a pair of acropetiolar, ± stipitate glands with a concave, discoid, yellow apex (0.5-1 mm diam.). Leaf blades chartaceous, ± entire, ovate, 4.5-22 × 3-15.5 cm, apex acuminate, base rounded to cordate; young leaves with a dense, farinose cover of whitish, stellate trichomes with brownish trichomes also present along the abaxial veins, both sides soon becoming glabrous, pale green when fresh and drying matte yellowish green to dark green-brown; venation prominent, with 6-9 pairs of brochidodromus, ± penninerved secondary veins (the lowermost pairs congested and appearing palmate), and cross-venulate tertiary venation; with ± stipitate glands in some of the axils of the secondary veins ( Fig. 1H). Inflorescences terminal, raceme-like thyrses 2-11 cm long, with pistillate flowers on the lower and middle part of the axis and staminate flowers towards the distal end, axes stellate-pubescent, flattened; bracts triangular, c. 2.5 mm long, caducous. Staminate flowers with stellate, subglobose buds 1.8-2 mm in diam., pedicels 1-4 mm long; sepals 5, shortly connate at base, lobes ovate, c. 2 × 1.8 mm, apex acute, inflexed at anthesis, abaxially stellate, adaxially sparsely ciliate, margins ciliate; petals 5, white, elliptic-obovate, 2.5-3 × 1-1.3 mm, recurved at anthesis, abaxially stellate and papillose, adaxially glabrous, margins ciliate; disc glands 5, opposite the sepals, sessile, ellipsoidal with an apical depression, c. 0.5 × 0.8 mm, yellowish; stamens 15-20, white, filaments 2-3 mm long, pilose at base, anthers broadly elliptic, c. 0.8-1 × 0.7- 0.9 mm; receptacle pilose. Pistillate flowers with stellate ellipsoid buds, c. 1.8 mm diam., pedicels 1-3 mm long; sepals 5, ovate, spreading at anthesis, c. 2.5 × 1.3-2.0 mm, pale green, apex acute, shortly connate at base, abaxially stellate, adaxially sparsely pubescent, petals often reduced, if present similar to the petals of the staminate flower; disc glands 5, opposite the sepals, sessile, ellipsoidal, c. 0.5 × 0.3-1.3 mm; ovary stellate, globoid, c. 2.5 mm diam; styles 3, 2- 3 mm long, each branch flattened and twice bifurcate, spreading, abaxially stellate, adaxially glabrous, yellow, turning brown, persistent. Capsules and seeds not seen.

Phenology. – This species has only been collected from September to March, presumably because it is deciduous during the dry season. Specimens in flower have been collected from September to December, with immature fruits in October.

Distribution, habitat and ecology. – This species has a disjunct distribution and has been collected in deciduous forests in western Antsiranana Province (Ambilobe, Ankarana National Park, and Sakaramy), northern Mahajanga (Ambodimotso and Bealanana), and in the Lac Alaotra area in Toamasina Province, growing on basalt, lateritic and sandy soils at 100-900 m in elevation ( Fig. 2C View Fig ).

Conservation assessment. – Croton scoriarum   has been collected only rarely from rather scattered localities, but may be extant in a wide area in central to northern Madagascar. With probably more than ten locations in three Provinces, we assigned this species as “Least Concern” [LC] according the IUCN Red List Categories and Criteria ( IUCN, 2012).

Vernacular names. – “Hazompondra” (Herb. Jard. Bot. Tana

5252).

Notes. –The species epithet scoriarum   refers to the volcanic substrate on which the type was collected.

The species can be distinguished from its congeners by its large mature leaves that are ovate with a rounded-truncate base and entire to shallowly undulate or denticulate margins. The leaves are densely whitish stellate-pubescent on both sides when young but then become almost completely glabrous with age ( Fig. 1H, 12 View Fig C-D). The shoots likewise become smooth, and usually dry a glossy dark reddish-brown. The mature bark is papery and thinly flaky. In the molecular phylogenetic study of Malagasy Croton   by HABER et al. (2017), C. scoriarum   was called “ Croton   sp. nov. K”, and it formed a clade with C. adenophorus   and C. bathianus   (therein called “ C. cf. loucoubensis   ”); all three accessions share an asparagine-arginine insert in maturase K. In his protologue, LEANDRI (1972), mentioned the specimen Service Forestier 26207 (P) from the Antsalova District of Mahajanga Province as possibly belonging to C. scoriarum   . We think that this specimen may be better included in C. crocodilorum Leandri   , or else treated as a separate species. Croton crocodilorum   is similar to C. scoriarum   but has smaller leaves with a cordate base and denticulate margin, and it appears to retain a dense stellate indument, at least on the abaxial side of the leaves. The specimens from the Lac Alaotra surroundings, some of which have been recognized as C. bathianus var. ambatondrazakae Radcl.   -Sm., all appear to have been collected at the onset of the rainy season (November) and have no leaves, or else very small leaves. This makes it difficult to confidently determine them to species, but the thinly flaky, glossy, and dark brown bark is consistent with their placement in C. scoriarum   , although further collections may prove them to be a distinct species.

Additional specimens examined. – MADAGASCAR. Prov. Antsiranana: Diana Reg., Ambilobe, 26.VII.1939, Decary 14584 (P); Two-track road from Sakaramy towards Mahatsinja , west of road from RN 6 to Joffreville , 12°25’59”S 49°16’19”E, 340 m, 27.X.2009, van Ee et al. 1118 ( MICH); ibid loc., van Ee et al. 1120 ( MICH); ibid loc., van Ee et al. 1129 ( MICH); ibid loc., 12°24’33”S 49°17’05”E, 321 m, 3.III.2016, van Ee et al. 2329 ( MICH, TAN); Ankarana National Park , 12°56’52”S 49°07’33”E, 118 m, 7.III.2016, van Ee et al. 2379 ( MICH, TAN). Prov. Mahajanga: Sofia Reg., Ambodimotso, bas-Befandriana Nord, 14.IX.1942, Herb. Jard. Bot.Tana 5252 (P). Prov. Toamasina: Alaotra-Mangoro Reg., Antsihanaka, XI.1936, Herb. Jard. Bot. 2202 (P); ibid loc., XI.1936, Herb. Jard. Bot. 2287 (P); Lac Alaotra ( G), s.d., Herb. Jard. Bot. 3959 (P) GoogleMaps   .

Croton tsiampiensis Leandri   in Ann. Mus. Colon. Marseille, sér. 5, 7: 79. 1939. ( Fig. 1I, 2B View Fig , 4 View Fig O-P, 13).

Lectotypus (designated here): MADAGASCAR. Prov. Mahajanga: Tsiampihy, près de l’embouchure de la Soahanina, 15.X.1932, Leandri 311 (P [P00389521]!; isolecto-: P [P00133302]!)   .

= Croton tsiampiensis var. ankaranensis Radcl.   -Sm., Gen. Croton Madag. Comoro   110. 2016. Typus: MADA- GASCAR. Prov. Antsiranana: Diana Reg., Massif de l’Ankarana , 4.XI.1990, Bardot-Vaucoulon 224 (holo-: P [P00123706]!), syn. nov.

= Croton tsiampiensis var. macrophyllus Radcl.   -Sm., Gen. Croton Madag. Comoro   110. 2016. Typus:MADAGAS- CAR. Prov. Mahajanga: Reserve Naturelle Bemaraha   GoogleMaps , Ambodiriana, c. 9 km E of Antsalova, 18º39’S 44º43’E, 100-125 m, 13-15.XII.1990, Gillespie 4139 (holo-: K!; iso-: MICH!, MO), syn. nov.

= Croton tsiampiensis var. microphyllus Radcl.   -Sm., Gen. Croton Madag. Comoro   111. 2016. Typus: MADA- GASCAR. Prov. Antsiranana: Diana Reg., P.K. 10 de la route Diego Suarez-Orangea , 13.XII.1963, Service Forestier 22956 (holo-: P [P00123706]!), syn. nov.

Shrubs or trees 2-6 m tall, dichotomously branching, internodes sometimes so short as to give the appearance of whorled branches; in all parts covered in whitish to ferrugineous, stellate trichomes many of which have a bristly, porrect (to c. 4 mm) central radius. Branches flattened on new growth but becoming terete with age, green at first, soon turning a matte pale gray (to reddish brown); red latex present in freshly cut stems. Stipules 8-30 × 1-5 mm, lanceolate, entire or incised, with marginal glands, caducous. Leaves deciduous, opposite. Petioles 1.2-12 cm long, adaxially canaliculate, stellatepubescent, usually with a pair of acropetiolar, ± stipitate glands with a concave, discoid, yellow apex (0.5-1 mm diam.). Leaf blades membranaceous to papyraceous, glandular-denticulate, broadly ovate to suborbicular, 3-18 × 3-15 cm, apex acuminate, base rounded to cordate; abaxially and adaxially conspicuously hirsute, pale green when fresh and drying matte pale green to brown; venation evident on both sides, prominent below, with 5-9 pairs of brochidodromus, ± penninerved secondary veins (the lowermost pairs congested and appearing palmate), and cross-venulate tertiary venation; with ± stipitate glands in some of the axils of the secondary veins ( Fig. 1I). Inflorescences terminal, raceme-like thryses 5-20 cm long, with pistillate flowers toward the base and staminate flowers towards the distal end, axes stellate, flattened; bracts triangular, 1.0- 2.5 mm long, caducous. Staminate flowers with stellate, subglobose buds 1.5-2.9 mm diam., pedicels 1-3 mm long; sepals 5, shortly connate at base, lobes ovate, c. 2 × 1.2 mm, apex acute, inflexed at anthesis, abaxially stellate, adaxially glabrous, margins ciliate; petals 5, white, elliptic-spatulate, 2.5-2.7 × 1-1.5 mm, recurved at anthesis, abaxially subglabrous and papillose, adaxially glabrous, margins ciliate; disc glands 5, opposite the sepals, sessile, ellipsoidal with an apical depression, c. 0.4 × 0.3- 0.6 mm, yellowish; stamens 12-15, white, filaments 1.5- 3.3 mm long, glabrous or pilose at base, anthers broadly elliptic, c. 0.5-1 × 0.5-0.8 mm; receptacle pilose. Pistillate flowers with stellate, ellipsoid buds c. 2.2 mm diam., pedicels 1-4 mm long; sepals 5, ovate, spreading at anthesis, 2.5-3 × 1.3- 2.3 mm, apex acute, shortly connate at base, abaxially stellate, adaxially glabrous except towards the apex, persistent in fruit; petals often reduced, 0.8-2.5 2.5 × 0.2-1 mm, linear to spathulate, recurved, glabrous but with a ciliate margin; disc glands 5, opposite the sepals, sessile, ellipsoidal, c. 0.4 × 0.8 mm; ovary densely hirsute, globoid, 1.5-3.7 mm diam; styles 3, 3- 4.2 mm long, each branch flattened and 2-3 times bifurcate, spreading, abaxially stellate, adaxially glabrous, persistent. Capsules 4-8 × 5-8 mm, densely hirsute, exocarp not separating ( Fig. 4O View Fig ), endocarp woody, 0.4-0.6 mm thick; columella 3.5-5.5 mm long, cornute, capitate. Seeds ±compressed-ellipsoid, 3.5-5.6 × 3-4.3 × 2-2.9 mm ( Fig. 4P View Fig ); testa glossy, verrucose, brown; caruncle narrowly reniform c. 0.7 × 2 mm.

Phenology. – This species has been collected only from October to March, presumably because it is deciduous during the remaining drier months of the year. Specimens in flower have been collected from October to February, and in fruit from October to January.

Distribution, habitat and ecology. – Croton tsiampiensis   has a disjunct distribution in northern Antsiranana and southern Mahajanga Provinces, respectively ( Fig. 2B View Fig ). It has been collected in deciduous, semideciduous, and evergreen forests, as well as in anthropogenic savannas, at 45-500 m in elevation, on sandy substrates and on tsingy limestone.

Conservation assessment. – This species appears to be widespread with fragmented populations in deciduous forests of northern and western Madagascar, including the the protected areas Ankarana, Beanka, Bemaraha, and Daraina. We therefore treat this species as “Near Threatened” [NT] according the IUCN Red List Categories and Criteria ( IUCN, 2012).

Notes. – The species epithet tsiampiensis   refers to the type locality, the Tsiampihy forest in Mahajanga Province   .

Croton tsiampiensis   is distinct for its broadly cordate leaves, large incised stipules, and very hirsute pubescence. It is superficially similar to C. ankarensis Leandri   , and Leandri’s description of that species was likely based on specimens representing different taxa, one of which is likely C. tsiampiensis   . The type of C. ankarensis, Perrier de la Bâthie   9830 from Ankara (Betsiboka Reg.), lacks laminar glands and has alternate leaves, as well as sparsely stellate-pubescent capsules. It is clearly different from C. tsiampiensis   and does not belong in the Adenophorus Group (it was placed in the Ankarensis Group by LEANDRI, 1939). The Leandri 103bis syntype from Bemaraha is nearly leafless, but the leaf scars are opposite. The pistillate flowers are much larger than in Perrier de la Bâthie 9830, but they conform to C. tsiampiensis   , as does the markedly hirsute and pale gray bark of the young branches. We therefore tentatively include Leandri 103bis in C. tsiampiensis   .

The varieties C. tsiampiensis var. macrophyllus   and var. microphyllus   that RADCLIFFE-SMITH (2016) described based on differences in leaf size are synonymized here. As with many of the new names in his manuscript, only single specimens are cited, and from our studies of a broader sample of specimens that are now available, it is evident that more variation in leaf size is found within, rather than between, populations. Nor is it meaningful to recognize C. tsiampiensis var. ankarensis   , which RADCLIFFE-SMITH (2016) distinguished from the type variety by its shorter petioles (<1 cm vs> 1.5 cm) and inflorescences, as well as slightly larger fruits. We have collected large-leaved specimens (van Ee et al. 2371) from the Ankarana population with leaves up to 16 × 11 cm and petioles up to 11 cm long, and Gillespie et al. 10696, also from Ankarana, is closer in inflorescence length and fruit size to the type of C. tsiampiensis   than to C. var. ankarensis   . There are currently no vernacular names recorded for Croton tsiampiensis   .

Additional specimens examined. – MADAGASCAR. Prov. Antsiranana: Diana Reg., Ankarongana , Analafandro , 12°37’50”S 49°31’28”E, 46 m, 23.II.2006, Andrianjafy et al. 1619 ( CNARP, MICH, MO, P, TAN) GoogleMaps   ; Ankarana , 13.X.1990, Bardot-Vaucoulon 131 (P)   ; ibid. loc., 4.XI.1990, Bardot-Vaucoulon 224 (P)   ; ibid. loc., 12°55’S 49°05’E, 150 m, 5.XI.1990, Bardot- Vaucoulon 252 (P, TAN) GoogleMaps   ; ibid. loc., 19. I.1991, Bardot-Vaucoulon 392 (P) GoogleMaps   ; ibid. loc., 200 m, 3.II.1960, Cours & Humbert 5614 (P) GoogleMaps   ; ibid. loc., 12°54’S 49°07’E, 150 m, 29.XI.1990, Gillespie 4085 ( MICH, MO) GoogleMaps   ; ibid. loc., 12°55’23”S 49°05’09”E, 110 m, 2.XI.2012, Gillespie et al. 10696 ( CAN, MICH, MO, TAN) GoogleMaps   ; ibid. loc., 30-350 m, 24. I- 29.II.1960, Humbert 32654 (P) GoogleMaps   ; SAVA Reg., Vohemar Distr., Daraina , Antsahabe forest , 13°12’37”S 49°33’27”E, 520 m, 11. I.2004, Nusbaumer 902 ( G, MICH, MO, P) GoogleMaps   ; ibid. loc., 13°12’36”S 49°33’43”E, 500 m, 21. I.2004, Nusbaumer 1076 ( G, MICH, MO) GoogleMaps   ; ibid. loc., 13°12’35”S 49°33’38”E, 500 m, 5.XI.2006, Randrianaivo et al.1400 ( CNARP, MICH, MO, P, TAN) GoogleMaps   ; Ankarana National Park, Maeva trail, 12°57’23 “S 49°07’04”E, 128 m, 6.III.2016, van Ee et al. 2370 ( MICH, TAN) GoogleMaps   ; ibid. loc., 12°57’23 “S 49°07’00”E, 153 m, 6.III.2016, van Ee et al. 2371 ( MICH, TAN) GoogleMaps   ; ibid. loc., Benavony trail, 12°56’55 “S 49°07’39”E, 124 m, 7.III.2016, van Ee et al. 2378 ( MICH, TAN) GoogleMaps   . Prov. Mahajanga: Melaky Reg. , collines au N d’Antsalova, bord de la Soahanina, 18.X.1932, Leandri 281 (K, P, TAN)   ; ibid loc., Leandri 283 (P); Beanka, partie S, Ambinda-Est , 18°02’41 “S 44°30’08”E, 261 m, 24.XI.2011, Gautier & Tahinarivony 5718 ( G, MO) GoogleMaps   ; Tsingy du Bemaraha, 4.X.1932, Leandri 103bis (K, P); Beanka , partie S   ; Ambinda-Est , 18°02’59”S 44°30’17”E, 260 m, 11.XII.2011, Nusbaumer et al. 3051 ( G, MICH) GoogleMaps   .

G

Conservatoire et Jardin botaniques de la Ville de Genève

MAO

Mircen Afrique Ouest

MO

Missouri Botanical Garden

TAN

Parc de Tsimbazaza

WAG

Wageningen University

MICH

University of Michigan

E

Royal Botanic Garden Edinburgh

I

&quot;Alexandru Ioan Cuza&quot; University

Kingdom

Plantae

Phylum

Tracheophyta

Class

Magnoliopsida

Order

Malpighiales

Family

Euphorbiaceae

Genus

Croton

Loc

Croton mayottae P.E. Berry & Kainul.

Kainulainen, Kent, Ee, Benjamin van, Razafindraibe, Hanta & Berry, Paul E. 2017
2017
Loc

Croton scoriarum

Leandri 1972: 68
1972
Loc

Croton tsiampiensis

Leandri 1939: 79
1939