Humbertacalia apocynifolia (Baker) Rabarim., Callm. & J. Calvo, 2023

Rabarimanarivo, Marina N., Callmander, Martin W. & Calvo, Joel, 2023, Synopsis of Humbertacalia (Compositae), a genus endemic to Madagascar and Réunion, Adansonia (3) 45 (7), pp. 93-113 : 98-101

3. Humbertacalia apocynifolia (Baker) Rabarim., Callm. & J. Calvo , comb. nov.

( Fig. 2 )

Vernonia apocynifolia Baker , Journal of the Linnean Society, Botany 20: 175 ( Baker 1883). — Senecio apocynifolius (Baker) Humbert , Mémoires de la Société linnéenne de Normandie 25: 140 ( Humbert 1923).

— Typus: Madagascar. Central Madagascar, s.d., Baron 1698 (holo-, K [ K000377694 ]!; iso-, P [ P00557671 , fragment]!) .

Vernonia voluta Baker , Journal of the Linnean Society, Botany 21: 415 ( Baker 1885). — Senecio leucopappus var. volutus (Baker) Humbert , Mémoires de la Société linnéenne de Normandie 25: 140 ( Humbert 1923). — Senecio volutus (Baker) Humbert , Flore de Madagascar et des Comores 189 (3): 764 ( Humbert 1963). — Humbertacalia voluta (Baker) C. Jeffrey , Kew Bulletin 47 (1): 83 ( Jeffrey 1992), syn. nov.

— Typus: Madagascar. sine loco, fl., Baron 2375 (holo-, K [ K000377690 image]!; iso-, P [ P00557586 , P00557587 ]!) .

Senecio leucopappus var. hederifolius Humbert , Notulae Systematicae 15 (4): 372 ( Humbert 1959). — Senecio leucopappus subvar. hederifolius (Humbert) Humbert, Flore de Madagascar et des Comores 189 (3): 763 ( Humbert 1963), syn. nov.

— Typus: Madagascar. Atsimo-Atsinanana Region [Prov. Fianarantsoa], massif de l’Ivakoany (centre-sud), [23°50’S, 46°26’E], 1250-1550 m, XI-XII.1933, fl., Humbert 12210 (lecto-, designated here, P [ P00557669 ]!; isolecto-, G [ G00412690 ]!, P [ P00557668 ]!) .

ADDITIONAL ICONOGRAPHY. — Humbert (1963: 761, fig. 139, 5 to 11, sub Senecio leucopappus ).

ETYMOLOGY. — The epithet apocynifolia refers to the resemblance of the leaves of this species with those of the members of the genus Apocynum L. ( Apocynaceae ).

VERNACULAR NAMES. — “Dingadingam-bahy” (Cours 2754); “Kimboimboilahy” (Malcomber et al. 1558); “Rongasoa” (Réserves Naturelles 9107); “Vahymasina” (Gautier & Chatelain 2806).

DISTRIBUTION AND ECOLOGY. — Humbertacalia apocynifolia comb. nov. is a widespread species, where it is found in humid, subhumid, and montane bioclimates, from Diana Region in the north to Anosy region in the south. It occurs in lowland, medium altitude moist evergreen humid forests and montane ericoid thicket but also in disturbed forests, mostly at the edge or in open areas of remnant forests or shrublands at high elevation, sometimes on laterite of gneiss, or along river banks, at c. 300 to 2100 m elevation.

CONSERVATION STATUS. — Humbertacalia apocynifolia comb. nov. has an extent of occurrence (EOO) of 181 654 km 2, an area of occupancy (AOO) of 284 km 2 and more than 40 locations with respect to the most serious plausible threat of shifting agriculture. It occurs within numerous protected areas namely Ambatofotsy, Ambohitantely, Andohahela, Andringitra, Anjanaharibe-Sud, Befotaka – Midongy du Sud, CAZ (Corridor Ankeniheny Zahamena, Main parcel), CAZ – Ankerana (Corridor Ankeniheny Zahamena), CAZ – Vohibe Forest (Corridor Ankeniheny Zahamena), Corridor forestier Marojejy-Anjanaharibe Sud-Tsaratanana nord, Corridor forestier Marojejy-Anjanaharibe Sud-Tsaratanana sud, Ivohibe, Kalambatritra, Mahimborondro, Mangabe, Manongarivo, Mantadia, Marojejy, Montagne d’Ambre, Ranomafana, Tsaratanana, and Zahamena. Being widely distributed and present in many protected areas, H. apocynifola is assessed as “Least Concern” [LC], according to IUCN Red List Categories and Criteria ( IUCN 2012).

SELECTED SPECIMENS EXAMINED. — Madagascar. Alaotra-Mangoro Region [ Prov. Toamasina ]: Ambatovy forest, 18°51’18”S, 48°17’55”E, 1151 m, 29.IX.2005, fl., Antilahimena et al. 3812 (MO, P[P04403972], TAN) ; Route Moramanga, Anosibe PK 57, [19°20’S, 48°13’E], IX.1953, fl., Bosser 6503 (P[P02397535]) ; Onibe, District d’Ambatondrazaka, [17°50’S, 48°33’E], 800- 1000 m, XI.1938, fl., Cours 939 (P[P02397534]) ; Androrangabe , [19°29’S, 48°04’E], 1200 m, 7.X.1945, fl. & m. fr., Cours 2754 (MO, P[P02397532, P04416354], TAN) ; Amparihifarambolosy ( Alaotra ), [17°28’S, 48°44’E], 1200 m, 12.X.1945, fl. & im. fr., Cours 2860 (P[P02397542]) ; Anosibe, S. de Moramanga , [19°26’S, 48°12’E], 7.IX.1942, fl., Decary 18452 (P[P02397467, P02397468, P02397469]) ; entre Mandritsara et Andilamena , [17°01’S, 48°35’E], 900-1200 m, XI.1937, fl. & im. fr., Humbert 18042 (P[P02397510, P04391733]) ; Mantadia PN, 18°53’S, 48°27’E, 1000 m, fl., Nicoll 169 (MO, P[P02478396], TAN) ; Ambatovy,18°49’15”S, 48°19’43”E, 1132 m, 20.X.2005, fl., Razanatsoa & Razafindasy 572 (MO, P[P04403973], TAN). — Analamanga Region [ Prov. Antananarivo ]: Mandraka , [18°53’S, 47°55’E], 5.VIII.1906, m. fr., Alleizette s.n. (P[P02397531]) ; Tampoketsa, Ankazobe , [17°55’S, 47°06’E], X.1962, fl., Bosser 16557 (P[P04388909, P04388913], TAN) ; Tampoketsa au N. d’Ankazobe, forêt d’Ambohitantely, [18°11’S, 47°17’E], 1600 m, X.1933, fl., Humbert 11131 (G, P[P02397544, P02397545], TAN) ; Ivohimanitra forest, [19°22’S, 46°42’E], 8.XI.1894, Forsyth Major 56 (G). — Anosy Region [ Prov. Toliara ]: Massif de Beampingaratra , col de Bevava au sommet de Bekoho , [24°26’S, 46°51’E], 1100-1500 m, 6-7.XI.1928, m. fr., Humbert 6429 (P[P02397548], TAN) ; Massif de Beampingaratra, cime mont Papanga , [24°26’S, 46°51’E], 1576 m, 3-4.XI.1928, fr., Humbert 6352 (G, P[P02397549, P02397550], US[US01832482]) ; Massif de Beampingaratra (sud-est), mont Papanga , [24°26’S, 46°51’E], 1400-1576 m, 3-4.XI.1928, fl., Humbert 6352bis (P[P02818089]) ; Massif de l’Andohahelo, vallée de Ranohela , [24°41’S, 46°49’E], 1000- 1200 m, 18.X.1928, m. fr., Humbert 6078 (P[P02397536]) ; Massif de l’Andohahelo, vallée de Ranohela , [24°42’S, 46°44’E], 300-1200 m, 18-26.X.1928, m. fr., Humbert 6229 (P[P03279255, P02397537], TAN) ; Haute vallée du Mandrare , [24°31’S, 46°47’E], 600-900 m, m. fr., Humbert 6509bis (P[P02397547]) ; Bassin supérieur du Mandrare, col de Vavara , [24°30’S, 46°42’E], 1300-1600 m, 10.XI.1928, m. fr., Humbert 6528 (P[P02397546]). — Atsimo-Atsinanana Region [ Prov. Fianarantsoa ]: Vondrozo , de Farafangana , [22°49’S, 47°19’E], 1.IX.1926, fl., Decary 4891 (P[P02397470]). — Atsinanana Region [ Prov. Toamasina ]: Brickaville , Anivorano-Sud , Ankerana , 18°26’06”S, 48°50’08”E, 594 m, 31.X.2005, fl., Andriantiana 312 (MO, P[P06898071], TAN). — Diana Region [ Prov. Antsiranana ]: Montagne d’Ambre, 12°37’S, 49°09’E, 01.X.2005, bud & fl., Acevedo-Rodríguez & Razafindraibe 14520 (MO, US) ; forest of Analanjahany, 4 km south Talaviana , 200 m west of RN 7, 14°09’19”S, 48°57’28”E, 2063 m, 24.IV.2001, fr., Birkinshaw et al. 874 ( MO, P [ P02397474 ], TAN) ; Antsatrotro, Réserve spéciale de Manongarivo , 14°05’S, 48°23’E, 1400 m, 26.V.1995, fl., Gautier & Chatelain 2806 (G, P[P02397466], TAN) ; Andranomalaza, Réserve spéciale de Manongarivo , 14°02’S, 48°25’E, 1660 m, 28.V.2000, fl., Gautier & Rakotomamonjy 3705 (G, P[P02818093], TEF) ; route de Joffreville à la montagne d’Ambre (station forestière des Roussettes ), X.1944, fl., Homolle 24 (P[P02397539]) ; Massif du Tsaratanana et haute vallée du Sambirano ( Réserve naturelle n° 4), [13°57’S, 48°52’E], 2000 m, XI.1937, fl., Humbert 18261 (G, P[P02397511, P02397512]) ; Massif de Marivorahona au sud-ouest de Manambato (haute Mahavavy du nord, district d’Ambilobe), [13°46’S, 48°59’E], 2000-2244 m, 18-26.III.1951, fl., Humbert & Capuron 25733 (P[P02397460, P03312478],TAN). — Haute Matsiatra Region [ Prov. Fianarantsoa ]: Parc national de Ranomafana , Parcelle 1, à l’est de Vohiparara , au nord de la Route nationale 25, 21°14’S, 47°23’E, 1100-1200 m, 8-18.X.1993, fl., Kotozafy 320 (G, K, MO, P[P00558049], TAN) ; Ankibory, canton et district Ambalavao , [22°13’S, 46°55’E], 18.VII.1955, fl., Rakotovao 7609 (P[P02397523]). — Ihorombe Region [ Prov. Fianarantsoa ]: Pic d’Ivohibe, [22°31’S, 46°57’E], 1500-2000 m, 5.XI.1924, m. fr., Humbert 3319 (P[P02397538, P03279254]) ; Massif de Kalam-batritra (centre-sud), mont Analatsitendrika , [23°27’S, 46°27’E], 1650-1850 m, XI.1933, Humbert 11919 (P[P02397551]) ; ibid. loco, fl., Humbert 11920 (P[P02397543]) ; 8 km ESE d’Ivohibe, 5.5 km SE d’Angodongodona, corridor forestier entre le Réserve spéciale d’Ivohibe et le Parc national d’Andringitra,22°25’S, 46°54’E, 1260 m, 9.XI.1997, fl., Messmer et al.562 (G, MO, P[P02397519]). — Sava Region [ Prov. Antsiranana ]: forêt d’altitude d’Ambohimirahavavy, montagne de Beampoko ,14°13’47”S, 49°08’19”E, 2062 m, 20.XI.2005, fl., Andriamiarinoro & Randrianarivony 29 (G, MO, P[P02397475], TAN) ; Pentes orientales du massif de Marojejy (nord-est) à l’ouest de la haute Manantenina , affluent de la Lokoho , [14°27’S, 49°42’E], 1400 m, 15-25.XII.1948, fl., Humbert 22477 (P[P02397526]) ; Partie occidentale du Massif de Marojejy (nord-est) de la vallée de l’Ambatoharanana au bassin supérieur de l’Antsahaberoka, [14°20’S, 49°40’E], 1400 m, 9.XI-2.XII.1959, fl., Humbert 31700 (P[P02397513]) ; Réserve naturelle Marojejy , along the trail to the summit of Marojejy est, NW of Mandena , 14°27’S, 49°47’E, 380 m, 05.X.1988, fl., Miller 3366 (MO, P[P02397518], TAN, US[US01832481]) ; forêt d’altitude d’Ambohimirahavavy, montagne de Beampoko, 14°13’41”S, 49°08’14”E, 1991 m, 17.XI.2005, fr., Randrianarivelo et al. 338 (G, MO, P[P02397458], TAN) ; Andapa, forêt Betaolana , 8.5 km au NW d’Ambodiangezoka, le long de la rivière Ambolokopatrika ,14°32’S, 49°26’E, 875 m, 11.X.1999, fl., Rakotomalaza & Ravelonarivo 1965 (G, MO, P[P02397515]) ; Andapa, Bealampona , environs d’Ampiferantany, 14°47’45”S, 49°27’54”E, 1161 m, 22.V.1995, Ravelonarivo & Rabesonina 808 (G, MO) ; Anjialavahely, Ankijanadambo , 14°14’58”S, 49°26’19”E, 1546 m, 7.III.2006, fl., Ravelonarivo et al. 1733 (G, MO, P[P02397456], TAN) ; Andrahanjo, Ambohimitsinjo , Sambava , [14°27’S, 49°42’E], 16.VIII.1957, fl., Réserves naturelles 9107 (P[P02397522]). — Sofia Region [ Prov. Mahajanga ]: Bemafo , 14°13’24”S, 49°03’44”E, 1750 m, fl., Andriamiarinoro 5 (MO, P[P02817285], TAN) ; Mangindrano, Ambohimiravavy massif,14°13’11”S, 49°4’01”E, 1887 m, 20.X.2005, fl., Callmander et al. 417 (G, MO, P[P02397473], TAN) ; Tsaratanana massif, N of Mangindrano, 14°10’24”S, 48°56’43”E, 1675 m, 21.X.2001, fl., Lowry et al. 5447 (K, MO, P[P02397520], TAN[ TAN000977 ]). — Vatovavy Region [ Prov. Fianarantsoa ]: Parc national Ranomafana , Parcelle 1, south of Ambohimiera , valley of Sakavolo river, 21°04’S, 47°29’E, 880-1100 m, 15-17.IX.1992, fl., Malcomber et al. 1558 (K, MO, P[P00558043], TAN) ; ibid. loco, Parcelle 3, Talatakely ,21°15’S, 47°27’E, 800-1000 m, 3-8.IX.1993, fl., Kotozafy et al. 229 (G, K, MO, P[P00558047], TAN!) ; ibid. loco, Vatoharanana, 40 km SO Ranomafana , 21°17’04”S, 47°26’00”E, 1025 m, 02.X.2000, fl., Rakotovao & Randriatafika 984 (MO, P[P02397524], TAN). — Sine loco, 1837-1838, Goudot s.n. (G) .

DESCRIPTION

Leaves petiolate; leaf laminas 3.5-8(-12) × 2-5(-8) cm, ovate, elliptic, or oblanceolate, base attenuate to rounded (sometimes nearly truncate or oblique), apex acute to obtuse (usually mucronate), margins entire or remotely mucronate-denticulate to shallowly dentate, glabrous to initially arachnoid on adaxial surface, glabrous to lanate on abaxial surface, venation pinnate (usually conspicuous on both surfaces, less noticeable on abaxial surface when covered by indumentum), rather chartaceous (rarely somewhat fleshy); petioles up to 2 cm long. Synflorescences axillary and terminal, thyrsoid-paniculiform. Capitula sessile to subsessile; involucres rather campanulate, glabrescent to arachnoid-floccose; involucral bracts (5-)8-10(- 13), 2-3 × 0.7-1 mm; supplementary bracts 4-8, 0.7-1.5 mm long. Florets 10-20, 3-4 mm long; corollas tubular, 5-lobed, whitish; anther bases caudate, as long as or slightly longer than filament collar; style branches truncate to obtuse with a crown of sweeping trichomes. Achenes 1.5-2 × c. 0.5 mm, rather cylindrical, 8-10-ribbed, glabrous, straw-coloured to brownish; pappus 3-4 mm long, whitish ( Fig. 2 ).

NOTES

Humbertacalia apocynifolia comb. nov. can be distinguished from the remaining species of the genus by its petiolate leaves, the thyrsoid-paniculiform synflorescences composed of sessile or subsessile capitula arranged in glomerules, the (5-)8-10(-13) involucral bracts, and the glabrous achenes. It is, however, a highly variable species concerning leaf shape and indumentum, which motivated Humbert to describe several infraspecific taxa and to propose different taxonomic treatments over time. In 1923, he recognized two varieties within Senecio leucopappus (under the concept currently ascribed to Humbertacalia apocynifolia comb. nov.; see comments under H. racemosa ): the typical variety embracing the glabrous or glabrescent forms, and Senecio leucopappus var. volutus (synonym of Vernonia voluta ) for including those forms with the abaxial leaf surfaces covered by a brownish floccose indumentum. In this regard, Humbert (1923) wrote: “Malgré la grande différence d’aspect des cas extrêmes, ces 2 variétés se séparent difficilement: l’exemplaire d’Alleizette a des feuilles presque glabres (passage à la var. α)” [Despite the difference in appearance of the extreme cases, these 2 varieties are difficult to separate: Alleizette’s specimen has almost glabrous leaves (transition to var. α)]. Later, in the frame of the Flore de Madagascar et des Comores, Humbert (1963) treated the var. volutus at specific rank but stated once again its similarity with S. leucopappus and the possibility of considering them mere subspecies of a single taxon (“[…] dont il pourrait être considéré comme une sous-espèce”). Humbert (1963: 757, 765) also supported the separation of S. volutus by its capitula mostly pedunculate. This is quite striking because the type material of Vernonia voluta (Baron 2375) shows mostly sessile capitula. The other material cited by Humbert (1963: 765) is a Baron’s quote [“localité indéterminée entre l’Antsih. et la côte E., E. Androna”, Baron (1903: 320)] and Humblot 81. This latter collection represents the type material of Senecio exsertus var. diffusus Humbert , here treated as Humbertacalia diffusa (Baker) J. Calvo, Rabarim. & Callm. , comb. nov., stat. nov. (see new combination below).

Between the glabrous or glabrescent plants (e.g. Forsyth Major 56, Lowry et al. 5447) and the floccose plants (e.g. Andriamiarinoro & Randrianarivony 29, Baron 2375), we studied multiple intermediate forms (e.g. Goudot s.n., Kotozafy et al. 229) that make any separation unworkable and even, in many cases, arbitrary. We also found some specimens displaying whitishlanate abaxial leaf surfaces and 12(-13) involucral bracts (e.g. Messmer et al. 562) and others having rather brownish-lanate abaxial leaf surfaces and (7-)8 involucral bracts (e.g. Callmander et al. 417). Against this background, we believe that it is appropriate to treat Humbertacalia apocynifolia comb. nov. in its broadest sense to include those forms hitherto ascribed to H. voluta . Accordingly, the synonymy is proposed.

With regard to the leaf margin variability, one finds specimens with entire margins (e.g. Humbert 11131), remotely mucronate-denticulate (e.g. Lowry et al. 5447), and even shallowly and remotely denticulate (e.g. Humbert 6446, Rakotovao & Randriantafika 984). Concerning the varietal name Senecio leucopappus var. hederifolius , it fits well within the aforementioned leaf variability of the species and we believe that it does not deserve taxonomic recognition. AlthoughHumbert (1959) indicated the holotype of this name at P, there are two duplicates kept in this herbarium. The best-preserved specimen is designated here as lectotype (P00557669).

Finally, it should be mentioned that the specimen Razakamalala et al. 3459 (MO, P[P04276658], TAN) has solitary capitula arranged in rather spiciform synflorescences. This feature does not match the typical synflorescences of Humbertacalia apocynifolia comb. nov., which are thyrsoid-paniculiform and composed of capitula arranged in glomerules. Although the remaining characters match well the morphology of H. apocynifolia comb. nov., for the time being we prefer excluding it from this taxonomic entity. Additional collections are needed to evaluate the consistency of such morphology.

Figures

FIG. 2. — Humbertacalia apocynifolia (Baker) Rabarim., Callm. & J. Calvo (Callmander 417, TAN): A, habit with leaf apex detail; B, capitulum; C, supplementary bract; D, involucral bract; E, floret; F, anthers; G, achene and pappus. Scale bars: A, 1 cm; B-E, G, 1 mm; F, 0. 5 mm. Drawings: Roger Lala Andriamiarisoa.