Croton hypochalibaeus Baill.

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, Candollea 71 (2), pp. 327-356 : 344-347

publication ID 10.15553/c2016v712a17


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Croton hypochalibaeus Baill.


Croton hypochalibaeus Baill. View in CoL in Bull. Mens. Soc. Linn. Paris 2: 262. 1890 ( Fig. 1D View Fig , 12 View Fig G-L, 13).

Lectotypus (designated here): MADAGASCAR: sine loc., s.d., Baron 5635 ( K [ K001040371 ]!; isolecto-: P [ P00133213 , P00133661 ]!).

Shrubs or trees to 5 m tall, dichotomously branching, with internodes 2-14 cm long separating tight clusters of leaves at the nodes, giving the appearance of whorled branches. Branches ± flattened on new growth and densely brown-lepidote, brown or gray, becoming terete and glabrous with age. Stipules awnshaped, 0.9-1.5 mm. Leaves congested and ± whorled at apex and nodes. Petioles 1-15 mm, adaxially canaliculate, without any apparent glands. Leaf blades papyraceous, entire or with shallow irregular undulations, narrowly elliptic to obovate, (7-)21-77(-145) × (5-)9-31(-45) mm, apex acute to long acuminate (rarely obtuse), base attenuate to cuneate; adaxial surface silvery-lepidote (young leaves appear silvery), glossy, (dark) green when fresh (turning orange in old leaves) and drying matte gray-green; venation impressed, not prominent, with 4-11 pairs of brochidodromus, ± penninerved secondary veins; abaxial surface densely silvery-lepidote and brown punctulate, the brown scales ± evenly scattered among silvery white scales; venation indistinct except for the brown-lepidote midrib. Inflorescences shortly racemose to fasciculate, 2-8(-10) mm long, axillary or terminal, with mostly staminate flowers, sometimes with 1-2 pistillate flowers at the base; axes densely brown-lepidote, flattened; bracts linear to spatulate, to 6.5 × 1.2 mm. Staminate flowers with brown-lepidote, subglobose buds 1.0- 1.4 mm diam., pedicels elongating from bud to anthesis, 1-4 mm long; sepals 5, firm, shortly connate at base, lobes broadly triangular to ovate, 1.0-1.6 × 0.9-1.5 mm, apex acute to rounded, inflexed at anthesis, abaxially brownlepidote, adaxially glabrous, white; petals 5, white, elliptic to spatulate, 2.0-2.9 × 0.7-1.1 mm, recurved at anthesis, abaxially papillate, adaxially glabrous, margins densely ciliate; disc glands/nectaries 5, opposite the sepals, sessile, triangular with an apical depression, 0.4-0.5 × 0.3-0.5 mm, yellow; stamens 10-18, white to pale yellow, filaments 1.1-3.2 mm long, ciliate, anthers elliptic, 0.5-0.9 mm long; receptacle pilose. Pistillate flowers with brown-lepidote buds 1.5-1.8 mm diam., pedicels 1-3(-5) mm long; sepals 5, firm, broadly elliptic, spreading at anthesis, 1.6-2.4(-5.5) × 0.9-2.2(-2.7) mm, apex acute and inflexed, shortly connate at base, abaxially lepidote, adaxially ± lepidote and ciliate towards apex, greenish white-green, persistent in fruit; petals usually absent/reduced; disc glands/ nectaries 5, opposite the sepals, sessile, ellipsoidal with a short apex, 0.2-0.6 × 0.6-1.0 mm, pale yellow; glandular filaments (in petal position alternating with the nectary lobes) 5, 0.3- 0.8 mm long; ovary subglobose, c. 2.0 mm diam., lepidote, styles 3, 2.3-5.0 mm long, flattened, each bifurcating 3-4 times, often with the first bifurcation congested and fused to appear 4-furcate, spreading, recurved at the apices, abaxially lepidote, adaxially glabrous (but appearing lepidote in some specimens where the edges of the style branches are rolled up), white, turning brown, persistent. Capsules 4.6-6.7 × c. 4.3 mm ( Fig. 7E View Fig ), smooth, (pale) brown, lepidote, exocarp not separating, endocarp woody, c. 0.2 mm thick; columella 3.8-5.2 mm long, cornute, capitate. Seeds ± compressed-ellipsoid ( Fig. 7F View Fig ), c. 4.0 × 3.0 × 2.5 mm; testa glossy, punctate, brown; caruncle reniform c. 0.7 × 0.5 mm.

Etymology. – The epithet refers to the steel-colored lepidote indumentum on the underside of the leaves.

Phenology. – Both flowering and fruiting specimens have been collected from October to April (we have not seen any specimens collected between May and September), indicating that C. hypochalibaeus is aseasonal in its phenology.

Distribution, habitat and ecology. – Croton hypochalibaeus is mostly restricted to the eastern montane forests and the central highland plateau of Madagascar (“tampoketsa”) at elevations of 800-1600 m, but also occurs as low as 675 m at Ankerana. Most collections are from Toamasina Prov. (Ambatovy, Andasibe, Ankerana, and Zahamena), but it has also been collected in Ambohitantely and Sohisika (Antananarivo Prov.) and as far south as Ivohibe in Fianarantsoa Prov. and Isalo National Park in Toliara Prov. Some doubtful specimens from Antsiranana Prov. are also mapped (see Fig. 1D View Fig ). It typically grows in primary forest understory but it also occurs along the edges of forests or in secondary woody vegetation.

Vernacular names. – “Lazalaza madinidravina”, “Lazalaza madinika”, “Tsiavalika”.

Notes. – The two specimens of Baron 5635 at P are sparser fragments of the more complete specimen at K. Since LEANDRI (1939) treated C. hypochalibaeus as a synonym of C. noronhae , the name has not been applied to contemporary Malagasy Crotons, but the two species differ both morphologically and ecologically. Croton noronhae is restricted to littoral, sandy-soil forests along the eastern coast of Madagascar and has dark reddish velvety shoots compared to smooth, brown-lepidote shoots in C. hypochalibaeus ; it also has evident acropetiolar glands, which are lacking in C. hypochalibaeus . In the Ambatovy checklist of PHILLIPSON et al. (2010, Table 1 View Table 1 ), some of the specimens of C. hypochalibaeus listed below were determined either as C. jennyanus , C. noronhae , C. sp. nov. B aff. jennyanus , or the nom. nud. “ Croton alceicornu Radcl. -Sm.” These all form part of a complex of small-leaved Crotons in Madagascar that have silvery- or coppery-lepidote leaf undersides and very condensed inflorescences. Just as with the group of large-leaved silvery Croton species that were first highlighted by LEANDRI (1972), it takes detailed field experience and careful examination of flowering and fruiting material to be able to successfully distinguish among the component species. The true C. jennyanus is restricted to northern Antsiranana Prov. at low altitudes and shows less evidence of sylleptic branching than C. hypochalibaeus . Also, its leaves have an acute to mucronate apex and a cuneate to rounded base (vs. an acute to long-acuminate apex and attenuate to cuneate base in C. hypochalibaeus ), and the leaves usually dries a nitid green above (vs. a matte gray-green in C. hypochalibaeus ), and are ferrugineous-punctate and (silvery) glossy below (vs. brown-punctulate and matte [greenish- or grayish-] white in C. hypochalibaeus ). Specimens that were previously identified as “ Croton alceicornu Radcl. -Sm., ined.” have smaller, rounder leaves than typical C. hypochalibaeus specimens, but we could find no consistent differences in floral characters between them. Still, closer study in the field and examination of better reproductive material may in the future justify recognition of a separate taxon for this entity.

There are some geographically outlying specimens that are referred here with some reservation; they are represented on the distribution map ( Fig. 1D View Fig ) by the four dots at the northern tip of the island. Ranirison 631 from the Ampondrabe forest in Daraina (12°57’29’’S 49°41’50’’E, 580 m, 11.IV.2004, G, P) seems to be a more reduced version of this species in terms of leaf size and compact growth. However, the label alludes to the sylleptic branching pattern that is typical of this species, and the habitat is described as a subhumid, high altitude forest. Similar specimens collected in the Antsahabe forest near Daraina, are Nusbaumer 986, (13°13’02’’S 49°33’11’’E, 950 m, 15.I.2004, G, P) and Rakotondrafara et al. 358 (13°13’06’’S 49°33’02’’E, 790 m, 1.XI.2005, MO, P). On the northwestern side of the island, Harder et al. 1590, from Montagne d’Ambre (12°30’48”S 49°10’59”E, 990 m, 15.IV.1993, MO, P), is also a close match to this species, but since it is the only collection we have seen from this isolated massif, we would like to see further material to confirm its presence there. Finally, Burivalova 186, from Andrafiamena, Anjahankely, (12°54’60”S 49°21’47”E, 726 m, 7.I.2010, G, P), may also belong here, but again, it would be helpful to see additional specimens to confirm its presence in this part of Antsiranana Prov.

Additional specimens examined. – MADAGASCAR. Prov. Antananarivo: Analamanga Region, Ankazobe Distr., Ankazobe, Firarazana , Ankafobe forest , 18°06’10”S 47°11’12”E, 1492 m, Andrianjafy 1910 ( MICH, MO, P, TAN); GoogleMaps ibid. loc., Andrianjafy 1914 ( MO, P, TAN); GoogleMaps ibid. loc., XI.1955, Bosser 8596 ( P); GoogleMaps Mandraka , route de Tamatave , 2.XI.1972, Debray 1848 ( P); Ankazobe, 29.IV.1943, Decary 19358 ( K, P); 25 km NNE Ankazobe, 18°06’S 47°11’E, c. 1500 m, 5.XII.1990, Gillespie 4106 ( K, MO); GoogleMaps Ambohitantely forest , c. 1600 m, X.1933, Humbert 11111 ( G, P); Manjato forest , 18°06’19”S 47°14’49”E, 13.IV.2007, Rakotoarivelo 62 ( MO, P); GoogleMaps Ankafobe forest , 18°06’21”S 47°11’14”E, 1464 m, 5.IV.2013, Randrianaivo et al. 2243 ( MO, P); GoogleMaps ibid. loc., 18°06’11”S 47°11’10”E, 14.XII.1999, Razafindrakoto et al. 30 ( K, MICH, MO, P, TAN); GoogleMaps Massif de Manohilahy, Anjozorobe , 22.VIII.1952, Service Forestier 5660 ( P); Sohisika Nature Reserve , 18°06’08”S 47°11’09”E, 1530 m, 20.X.2009, van Ee et al. 1011 ( MICH, TAN); GoogleMaps below village of Andranofeno Sud , 18°05’02”S 47°10’49”E, 1430 m, 24.II.2016, van Ee et al. 2261 ( MICH, MO, P, TAN). GoogleMaps Prov. Fianarantsoa: [Ihorombe Region], Ifandana , 7.IX.1926, Decary 5246 ( K, P); Ivohibe Distr., Réserve spéciale du Pic d’Ivohibe , Marovitsika forest , 22°28’49”S 46°56’49”E, 930 m, 18.X.2000, Hoffmann et al. 237 ( G, K, P); GoogleMaps [ Amoron’i Mania Region], Faliarivo à l’W d’Ambositra , 1600 m, 15.I.1955, Humbert & Capuron 28034 ( K, P); [ Ihorombe Region, Ihosy Distr.] Isalo , Canyon des Singes , 15.IV.67, Jacquemin H280J ( K); ibid. loc., 22°29’S 45°23’E, c. 800 m, 4.XI.1994, Lewis & McDonagh 1260 ( K, MO); GoogleMaps [ Vatovavy-Fitovinany Region, Ifanadiana Distr.], Parc National Ranomafana , 21°15’S 47°27’E, c. 1100 m, 12.XI.1991, Malcomber et al. 1052 ( MICH, MO, P). GoogleMaps Prov. Toamasina: Alaotra-Mangoro Region, Moramanga Distr., Ambatovy , 18°51’32”S 48°19’02”E, 1095 m, 30.X.2005, Antilahimena & Edmond 3894 ( G, K, MO, P, TAN); GoogleMaps ibid. loc., 21.X.2005, Antilahimena & Edmond 4091 ( K, MO); GoogleMaps ibid. loc., 18°51’58”S 48°17’11”E, 1012 m, 26.I.2007, Antilahimena 5221 ( MO, P, TAN); GoogleMaps Sahaviana forest , 18°51’33”S 48°17’10”E, 999 m, 14.II.2007, Antilahimena 5339 ( MO, P, TAN); GoogleMaps Maharombotra forest , 18°51’45”S 48°16’13”E, 982 m, 11.X.2008, Antilahimena et al. 6676B ( MICH, MO, P, TAN); GoogleMaps Ankoditrazo forest , 18°50’06”S 48°15’50”E, 954 m, 24.II.2009, Antilahimena et al. 6978 ( MO, P, TAN); GoogleMaps ibid. loc., 18°50’11”S 48°15’51”E, 967 m, 24.II.2009, Antilahimena et al. 6981 ( MICH, MO, P, TAN); GoogleMaps Ankosy forest , 18°49’13”S 48°16’11”E, 1031 m, 21.IV.2009, Antilahimena et al. 7057 ( MICH, MO, P, TAN); GoogleMaps Savaharina forest , 18°52’08”S 48°20’26”E, 1065 m, 12.XI.2009, Antilahimena & F. Edmond 7174 ( MICH, MO, P, TAN); GoogleMaps Antsinanana Region, Brickaville , Anjahamamy , Anivoranokely , Ankerana forest , 18°24’26”S 48°49’23”E, 676 m, 25.I.2012, Antilahimena 8064 ( MO, P, TAN); GoogleMaps Moramanga Distr., Andasibe, Mantadia National Park , 18°47’54”S 48°25’35”E, 961 m, 20.III.2013, Antilahimena et al. 8614, ( MICH, MO, P, TAN); GoogleMaps Andasibe, Analamazaotra , 18°55’31”S 48°25’58”E, 1025 m, 18.II.1990, Bernard et al. 1990 ( MICH, MO, P, TAN); GoogleMaps Anony, pays Sihanaka , 3.IX.1937, Boiteau & Cours 2954 ( P); Moramanga, Route d’Anjiro , 900 m, XI.1938, Cours 803 ( P); Ambatondrazaka Distr., Onibe , 800-1000 m, XI.1938, Cours 988 ( P); Manambato à Amboditfonana , 1200 m, 11.X.1945, Cours 2833 ( P); Zahamena, 22.III.1941, Decary 16708 ( P); chutes du Maningory , XII.1944, Homolle 537 ( P); Ambatovy, 1.VII.1966, Peltier 5997 ( K, P); ibid. loc., 18°51’34”S 48°18’25”E, 1050 m, 3.III.1997, Rakotomalaza et al. 1220 ( MO, P, TEF); GoogleMaps Analamazaotra, 18°56’07”S 48°25’52”E, 1014 m, 19.XII.2013, Ramahenina et al. 320 ( MO, P, TAN); GoogleMaps Ambatondrazaka Distr., Manakambahiny-Est , Anosivola , Zahamena , 17°43’42”S 48°40’27”E, 875 m, 2.XI.2001, Randrianasolo et al. 259 ( CNARP, DAV, MO, P, TEF); GoogleMaps Ambatoaranana, Corridor Forestier Analamay Mantadia , 18°47’38”S 48°24’39”E, 1019 m, 23.IV.2012, Rasoazanany & Ratolojanahary 77 ( MICH, MO, P, TAN); GoogleMaps Analamazaotra, Amboasary , 18°57’13”S 48°26’43”E, 1008 m, 14.II.2013, Rasoazanany et al. 324 ( MICH, MO, P, TAN); GoogleMaps Ambatovy, 18°51’46”S 48°16’14”E, 984 m, 20.II.2010, Rasolofoniaina et al. 14 ( MO, P, TAN); GoogleMaps Ambatondrazaka, Manaka Est , 2.XI.1962, Réserves Naturelles 12231 ( P, TEF); Ambatondrazaka, Maheriara , 11.VII.1954, Service Forestier 10543 ( P); Ambatovy, 18°51’52”S 48°16’30”E, 1004 m, 22.III.2016, van Ee et al. 2464 ( MICH, MO, P, TAN); GoogleMaps ibid. loc., van Ee et al. 2465 ( MICH, MO, P, TAN); GoogleMaps ibid. loc., 18°52’08”S 48°20’26”E, 1053 m, 23.III.2016, van Ee et al. 2469 ( MICH, MO, P, TAN); GoogleMaps ibid. loc., van Ee et al. 2470 ( MICH, MO, P, TAN); GoogleMaps ibid. loc., van Ee et al. 2471 ( MICH, MO, P, TAN); GoogleMaps ibid. loc., 2472 ( MICH, MO, P, TAN); GoogleMaps Analamazaotra, 24.X. 1912, 900 m, Viguier & Humbert 989 ( P). Prov.Toliara: Anosy Region, Betroka Distr., Ivahona, Réserve Spécial de Kalambatritra , forêt d’Analamaro , 23°28’14”S 46°23’38”E, 1390 m, 4.XI.2005, Andrianjafy et al. 446 ( MO, P, TAN); GoogleMaps ibid. loc., 23°25’12”S 46°26’45”E, 1359 m, 23.V.2005, Andrianjafy et al. 1070 ( K, MO, P, TAN). GoogleMaps


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