Homalium ovatifolium Appleq.

Applequist, Wendy L., 2018, A revision of Homalium sect. Odontolobus (Salicaceae) endemic to Madagascar, Candollea 73 (1), pp. 27-48: 38-43

publication ID

http://doi.org/ 10.15553/c2018v731a4

persistent identifier

http://treatment.plazi.org/id/03CAA927-3A13-FFA2-E757-F98AFA7D2E61

treatment provided by

Carolina

scientific name

Homalium ovatifolium Appleq.
status

 

7. Homalium ovatifolium Appleq.   , spec. nova ( Fig. 4 View Fig ).

Holotypus: MADAGASCAR. Prov   . Antsiranana: Ambilobe, Marivorahona, village le plus proche Betsimiranja , forêt d’Andohan’Antsohihy, Ambohibe, RN 6 à 1 km au SE d’Ambilomagodra, 13°02’31’’S 49°09’19’’E, 100 m, 17.VII.2005, fl., Randrianaivo et al. 1206 (MO-6082912!; iso-: CNARP, P [ P04679126]!, TAN) GoogleMaps   .

Homalium ovatifolium Appleq.   differs from H. longistaminum H. Perrier   in having leaves larger, (4.2-)6.2-10.2 × (2.1-) 3.1-5.2 cm (vs (3.2-)3.5-7.5 × 1.6-3.3(-4.8) cm), ovate (to elliptical) (vs irregularly elliptical to broadly elliptical, ovate or

1 cm 1 cm 1 cm

Fig. 3. - Homalium moniliforme subsp. littorale Appleq. A. Flowering   branch; B. Flowers; C. Inflorescence; D. Leaf (upper surface); E. Leaf (lower surface). [Rabehevitra et al.516, TEF] [Drawings: R.L. Andriamiarisoa]

Candollea   73, 2018 Homalium sect. Odontolobus   ( Salicaceae   ) in Madagascar - 39

1 cm

rarely lanceolate) with the base rounded (vs convex to rounded), margins less toothed, sometimes subentire (vs irregularly crenate apically to crenate-serrate for most of their length), apex acute to acuminate (vs acute to obtuse or rounded, rarely shortacuminate), and petals narrowly oblong (vs oblong to obovate), the abaxial surface pubescent and the adaxial surface largely glabrous (vs both surfaces pubescent, the abaxial surface densely so and often the base of the adaxial surface densely so). It differs from H. masoalense Appleq.   in having possibly broader leaves, ovate or rarely elliptical (vs often lanceolate), with the petiole longer, 5-11 mm long (vs 3-5.5 mm long); inflorescences shorter, (2.2-) 4-6.5 cm long (vs 5-11 cm long), often canescent (vs moderately pubescent), the flowers more often pedicellate with pedicels 0.5-1 mm long (vs absent or up to 0.5 mm long); sepals ovate to deltoid or narrowly deltoid, (0.3-)0.4-0.5(-0.7) mm long (vs oblong-lanceolate to narrowly oblong, 1.2-1.4 mm long); petals 0.8-1.2 mm long (vs 1.5-1.7 mm long), much longer than sepals (vs only moderately longer).

Tree to 10 m tall, 50 cm dbh; young twigs glabrous. Leaves: petiole 5-11 mm long, glabrous; blade ovate (elliptical), (4.2-) 6.2-10.2 × (2.1-) 3.1-5.2 cm; base rounded; margins irregularly crenate-serrulate, sometimes with only 1 tooth per side, to slightly wavy or subentire; apex acute to acuminate. Inflorescences racemose, (2.2-) 4-6.5 cm long, canescent to moderately pubescent; flowers often in clusters of 2 or 3, pedicellate, with pedicels 0.5-1 mm long, or subsessile; bracts broadly ovate to deltoid or transversely oblong; bracteoles very thick, to subterete at base, densely pubescent, often caducous. Flowers 7-8-merous; sepals ovate to deltoid or narrowly deltoid, (0.3-) 0.4-0.5(-0.7) mm long; petals narrowly oblong, 0.8-1.2 mm long, margins long-ciliate, abaxial surface pubescent, mostly glabrous adaxially, apex rounded; filaments 1.4-1.9 mm long; upper surface of ovary densely pubescent to moderately so in fruit; styles 3-4, 1.3-1.8 mm long.

Vernacular name. – “Taindalitra” (Guittou et al. 160).

Distribution, ecology and conservation status. – Homalium ovatifolium   is known from only two collections and a single location in deciduous forests at low elevation in extreme northern Madagascar in the western edge of the Andrafiamena Andavakoera protected area. Even if the only known location is within the protected area network, the new species is under threat and can be affected by a single event (e.g., fire), so its conservation status should be considered “Vulnerable” [VU D2].

Notes. – Homalium ovatifolium   has clear affinities to H. longistaminum   , which likewise has a canescent or mostly densely pubescent inflorescence, fleshy, densely pubescent bracteoles and long filaments and styles. It differs in its larger leaves, (4.2-) 6.2-10.2 × (2.1-) 3.1-5.2 cm (vs (3.2-)3.5-7.5 × 1.6- 3.3(-4.8) cm), which are more usually ovate with a rounded base, often long-acute to acuminate apex and few-toothed, shallowly wavy or subentire margins, and its narrow, less pubescent petals.

Interestingly, the two taxa are found at the opposite extremes of latitude, H. ovatifolium   being confined to the extreme north of Madagascar and H. longistaminum   to the southeast. It also is likely to be closely related to H. masoalense   , which is from northeastern Madagascar and shares the unusual character of often ovate, acuminate leaves, as well as long filaments and styles. Homalium masoalense   has often lanceolate, short-petiolate leaves and larger flowers (petals 1.5-1.7 mm long) with the sepals more similar to the petals in length (1.2- 1.4 mm long) and narrowly oblong to oblong-lanceolate.

Paratypus. – MADAGASCAR. Prov. Antsiranana: Ambilobe, Tanambao Marivorahona, Betsimiranja , Andohan’Antsohy , 4 km au NE de Betsimiranja , 13°02’32’’S 49°09’24’’E, 76 m, 2.VII.2005, fl. & fr., Guittou et al. 160 ( MO, P, TAN) GoogleMaps   .

8. Homalium parkeri Baker   in J. Linn. Soc., Bot. 20: 150. 1883.

Lectotypus (designated by SLEUMER, 1973: 309): MADAGASCAR. Prov. Antananarivo: Andrangolaoka, s.d., Parker s.n. ( K [ K000231480] image seen)   . Syntypus: MADAGASCAR. Prov. Antananarivo: forests of Imerina, s.d., Baron 1295 ( K [ K000231479] image seen, TAN [ TAN000592 View Materials ] image seen)   .

Tree to 20 m tall, 36 cm dbh, or shrub; young twigs glabrous (glabrate). Leaves: petiole 2.5-7(-8) mm long, glabrous (glabrate); blade elliptical to narrowly elliptical (to narrowly obovate, ovate or obovate), (2.8-)4-7.3(-9.3) × 1.3-3.1 (-3.4) cm; base cuneate (moderately convex, attenuate); margins serrate with rounded tooth apices; apex acute (rounded, aberrantly emarginate). Inflorescences spicate, (1.8-) 3-7(-11.5) cm long, minutely pubescent (glabrate); flowers clustered, sessile; bracts broadly to transversely deltoid; bracteoles deltoid, minute, caducous. Flowers 5-7-merous, pale green to yellowish; sepals deltoid (ovate), 0.2-0.4(-0.5) mm long; petals ovate (oblong-ovate), 0.7-1.5 mm long, glabrous (sparsely pubescent on abaxial surface), apex acute to rounded; filaments 0.3-0.6 mm long; upper surface of ovary shortpubescent, usually densely; styles (2-)3(-4), 0.2-0.5 mm long.

Vernacular names. – “Hazombato” (Anonymous 19, Hong-Wa et al. 392, Lehavana et al. 487, Service Forestier 16807, 19957, 28755); “Hazombatofotsy” (Louvel 43); “Hazombatomainty” (Service Forestier 16010, 16822); “Hazomby” (Service Forestier 595, 1043, 3926, 6006, 10370, 15990); “Hazompoza” (Service Forestier 7592); “Moara” (Réserves Naturelles 9460); “Ramaindafa” [?] (Réserves Naturelles 10472); “Ranga” (Service Forestier 15873).

Distribution, ecology and conservation status. – Homalium parkeri   is widespread in humid forests of eastern Madagascar, extending to high-elevation montane moss forest. A preliminary assessment of its conservation status should be “Least Concern” [LC].

Selected material examined. – MADAGASCAR. Prov. Antananarivo: Ambohitantely RS, 1620 m, 18°11’52.5’’S 47°17’03’’E, 7.III.2004, fl., Almeda et al. 8645 ( MO) GoogleMaps   ; Angavokely ( Carion ), V.1956, fl., Bosser 9575 ( P)   ; PK 138 de la route Tananarive-Majunga , 8.VII.1971, post-fl., Cremers 1636 ( MO)   ; W Imerina, Andrangolaoka, III.1881   , fl. & fr., Hildebrandt 4102 ( P [2 sheets])   ; Firarazana, forêt de Manjato , 18°06’19’’S 47°14’43’’E, 1447 m, 6.VII.2005, fl., Hong-Wa et al. 392 ( MO, P) GoogleMaps   ; 7 km E of Anjozorobe , 18°22’S 48°00’E, 1350 m, 2.IV.1988, fl., Lowry & Randrianasolo 4419 ( MO, P) GoogleMaps   ; Ambatolaona , 1700 m, VII.1914, fl., Perrier de la Bâthie 6720 ( P)   ; Tsinjoarivo, Ambatotsipihina , 22.XI.1949, fl., Service Forestier 1043 ( P)   ; Antsahambavy, Manjakandriana , 14. V.1956, fl., Service Forestier 15873 ( P)   ; Ambohidraondriana, Ankazobe , 3. V.1956, fl., Service Forestier 15990 ( P)   ; Ambatondradama au N d’Ambohimanga , 30.IV.1957, fl., Service Forestier 18027 ( P)   ; Tsiazompaniry, forêt d’Ambohimangakely , 6.IV.1961, fl., Service Forestier 19894 ( P)   ; Ibity massif W, Vohipisaka , 20°09’42’’S 46°58’54’’E, 1423 m, 29.II.2004, fl., Skema et al. 22 ( MO) GoogleMaps   ; SW Andranofeno Sud village , 18°04’59’’S 47°10’26’’E, 1407 m, 5.IV.2004, fl., Skema et al. 54 ( MO) GoogleMaps   . Prov. Antsiranana: Manongarivo RS, 14°05’S 48°23’E, 1470-1570 m, 14-15.IV.1992, fl., Malcomber et al. 1495 ( MO, P) GoogleMaps   ; SW edge of Anjanaharibe-Sud Reserve , 14°48’15’’S 49°26’45’’E, 1000-1100 m, 6.VIII.1997, fr., McPherson 17257 ( MO) GoogleMaps   ; Anjanaharibe-Sud , 14°47’45’’S 49°27’54’’E, 1161 m, 22. V.1995, fl., Ravelonarivo & Rabesonina 811 ( G, K, MO, P) GoogleMaps   ; Andranomilolo, 13 km à l’W du village d’Andranopositra , 14°19’16’’S 49°17’56’’E, 1462 m, 10.XI.2006, fl., Ravelonarivo et al.2015 ( MO, P) GoogleMaps   ; Befingotra, Andranotsarabe , 14°45’11’’S 49°28’49’’E, 762 m, 21.IV.1997, fl., Razafindramora et al. 26 ( MO) GoogleMaps   . Prov. Fianarantsoa: Andringitra , 26.II.1938, fl., Herb. Jard. Bot. 3141 ( P [2 sheets])   ; Ranomafana, W side of Namorona riv., 21°16’S 47°21’E, 1080 m, 6.III.1992, fl., Malcomber et al. 1317 ( MO, P) GoogleMaps   ; Ambalamanakana , 30 km S d’Ambositra sur RN 7, 20°44’06’’S 47°11’37’’E, 1650 m, 26.III.1996, fl, Rakotomalaza et al. 678 ( MO) GoogleMaps   ; Ranomafana , parcelle n° 3, 21°15’30’’S 47°25’E, 900-1100 m, 14. VI.1994, fr., J. Randrianasolo et al. 65 ( MO) GoogleMaps   . Prov. Mahajanga: Ambalotsangana, forêt de Makira , 15°31’S 49°05’’ E, 1169 m, s.d., fl., Lehavana et al.487 ( MO, P)   . Prov. Toamasina: Fkt. Ampita [m]be, Ambatovy , Ampanatovana forest , 18°51’17’’S 48°19’07’’E, 1085 m, 9. VI.2008, fl., Antilahimena et al. 6277 ( G, MO) GoogleMaps   ; Andapanomby, près de la riv. Ampandisanana, Makira NW, 15°21’17’’S 49°06’25’’E, 25.IV.2007, fr., Bernard & Birkinshaw 456 ( G, MO, P) GoogleMaps   ; Fkt. Ambohibato, forêt de Rianan’i Galy , 18°39’32’’S 47°57’56’’E, 1291 m, 10.IV.2005, fl., Raharijaona et al. 72 ( MO) GoogleMaps   ; Mantadia PN, Andranomanamponga , 18°50’23’’S 48°26’31’’E, 1110 m, 19.III.2013, fl., Ramahenina et al. 224 ( G, MO, P) GoogleMaps   ; Zahamena PN, campement Analalentitra , 17°32’47’’S 48°44’21’’E, 1235-1400 m, 29.IX.2001, fr., Randrianjanaka et al. 629 ( MO) GoogleMaps   ; Fkt. Ampitambe, Ambatovy, forêt d’Analamay , 18°49’07’’S 48°19’26’’E, 1138 m, 5.IX.2011, fl., Ravelonarivo 3950 ( G, MO) GoogleMaps   ; Ambatondrazaka, Manaka Est , 27.VII.1960, fl., Réserves Naturelles 10472 ( P)   ; Bekiritsika [?], Lakato , 8.X.1953, fl., Service Forestier 7592 ( P [2 sheets])   ; Perinet, km 7 Antaniditra , 5. V.1954, fl., Service Forestier 10370 ( P)   ; W du massif de l’Ampahana, à l’E de Fierenana, 950-1300 m, 10-16.III.1969, fl., Service Forestier 28755 ( MO, P)   .

9. Homalium planiflorum (Tul.) Baill.   in Bull Mens. Soc. Linn. Paris 1: 574. 1886.

Ξ Blackwellia planiflora Boivin ex Tul.   in Ann. Sci. Nat., Bot. ser. 4, 8: 64. 1857 [nom. conserv. prop.; APPLEQ- UIST, 2017].

Ξ Blackwellia gracilis Blume   in Mus. Bot. Lugd.-Bat. 2: 26. 1856.

Holotypus: MADAGASCAR: “Ile Ste. Marie”, s.d., Richard 297 ( L [ L0010991] image seen; iso-: G [ G00018396] image seen, P [ P00375177, P00375178]!)   .

Tree to 30 m tall, 60 cm dbh; bark young twigs glabrous (minutely pubescent when very young). Leaves: petiole (2-)3- 8(-14) mm long, glabrous (to sparsely and minutely pubescent); blade narrowly elliptical to elliptical or oblanceolate (aberrantly obovate), (2.8-)3.5-10.3 × 1-4 cm; base convex (cuneate to attenuate); margins crenate-serrate to serrulate, at least apically (partly subentire); apex acute to acuminate (to rounded, emarginate, cuspidate). Inflorescences racemose (paniculate with a few long branches, racemiform panicles), sometimes clustered terminally, (2.2-)5-10(-22) cm long, moderately to sparsely short-pubescent; flowers mostly in small clusters, pedicellate with pedicels (0.4-)1-3(-3.5) mm long; bracts broadly ovate-deltoid to transversely ovate; bracteoles ovate to deltoid, small, not thickened, caducous. Flowers 7-8 (-9)-merous, whitish to pale green, pale yellow or creamcolored or pink to reddish; sepals lanceolate to narrowly oblong-lanceolate (ovate), 0.5-0.9(-1.1) mm long; petals oblanceolate (to broadly spatulate, narrowly obovate, to somewhat oblong or narrowly elliptical), 1-1.7 mm long, margins ciliate and both surfaces sparsely pubescent to glabrate, apex acute to rounded; filaments (0.5-)0.6-1.2(-1.4) mm long; upper surface of ovary moderately pubescent; styles 3-4, (0.4-) 0.8-1.4 mm long.

Notes. – Most specimens assigned to H. planiflorum   have white to pale green or yellowish flowers. A group of specimens from southeastern Madagascar that are characterized by pink or reddish flowers are herein segregated as subsp. roseiflorum Appleq. While   specimens of subsp. planiflorum   have sometimes large leaves and racemes usually borne along the length of the twigs, those of subsp. roseiflorum   often have relatively small leaves and relatively large (though not long) distal clusters of racemes, or occasionally paniculate inflorescences borne well below twig apices; however, these characters are not fully consistent. Several specimens from the extreme southeast, where both subspecies occur, are not assigned to either subspecies, though these collections generally have narrow leaves of modest size, typical of subsp. roseiflorum   . One is sterile and two are only weakly flowering with one or two racemes, so subspecies identity cannot be confidently assigned without information on flower color. Two other collections are described as having possibly reddish flower color (“terre brûlée” according to Cloisel and “fulvo-rosei (sordid)” according to Bernardi) but the distribution of their well-developed inflorescences appears to be more consistent with subsp. planiflorum   , and flowers may brown as they turn to fruit. The inability to assign identities to some specimens in the zone where these taxa are sympatric supports a view that they are not fully genetically isolated, and that the distinctions between them are not adequate to justify recognition at the species level. Alternatively, the intermediate specimens could be interpreted as hybrids between two distinct species; however, because three fixed differences between the two morphological forms have not been observed, the conservative approach of treating them as conspecific has been preferred.

Service Forestier 9952 (Andovolava, Nosy-Varika, 14.XI.1953) is a specimen in poor condition with few flowers; the leaves are very large and broad (up to at least 10 × 5.5 cm). It may represent a regional variant, an aberrant individual, or an undescribed species; the available material is inadequate to clarify its status. Additional collections from this population would be highly desirable.

Blackwellia planiflora   was published in 1857, the year after B. gracilis Blume   , though its author, Tulasne, was apparently unaware of the latter publication. The citation of Richard 297 in the protologue of B. gracilis   explicitly referred only to the duplicate at L, which is therefore its holotype. The protologue of B. planiflora   cited two syntype gatherings, Boivin 1847 and Richard 297; three duplicates each of the former are present at P and G, and two of the latter at P. PERRIER DE LA BÂTHIE (1946: 92) chose Boivin 1847 as “type” (i.e., the lectotype) without selecting among the available duplicates. Under Art. 52.2 of the ICN ( MCNEILL et al., 2012), the citation of Richard 297, which included the holotype of B. gracilis   , in the protologue of B. planiflora   would appear to make the latter a superfluous and illegitimate name. Past literature has implicitly treated it as being the citation only of duplicates that were available to Boivin and Tulasne, not the duplicate at L that they presumably did not have access to (e.g., SLEUMER, 1973: 248). By that view, B. planiflora   need not be treated as illegitimate. However, Art. 9.5 of the ICN states that the citation of a gathering, if not qualified or limited, is equivalent to the citation of all duplicates of that gathering, even those not seen or known of. Tulasne did not indicate that only material at P was used. The informal practice of treating a duplicate in an author’s home institution as a holotype despite the absence of a qualifying statement is seen in the literature (see Homalium lucidum   above), but normally in cases that do not involve questions of legitimacy. Hence Blackwellia planiflora   is illegitimate due to the citation of the holotype of B. gracile   , which is therefore also the obligate type of B. planiflora   , regardless of Perrier de la Bâthie’s attempt to select another gathering as the (lecto)type.

This creates serious problems, because under the ICN, the species under question here would have no legitimate name. Blackwellia gracilis Blume   cannot now be transferred to Homalium   and retain that epithet because of the existence of H. gracile Briq.   , a replacement name for Blackwellia gracilis Vieill.   [nom. illeg., non Blume]. However, because Homalium gracile   had not yet been published when H. planiflorum   was described, H. planiflorum   as a replacement name credited to Baillon would also be illegitimate (see Art. 58, Note 1, of the ICN; MCNEILL et al., 2012). The publication of a new name would therefore be required. However, since this is the most common species of its section, introducing an entirely unfamiliar name would cause some confusion among botanists. A proposal to conserve Blackwellia planiflora   to permit the continued use of Homalium planiflorum   (the preferable approach, since Prop. 235 to amend the ICN to permit this ( WIERSEMA et al., 2016) was accepted at the 2017 Botanical Congress) has therefore been offered ( APPLEQUIST, 2017) but will not be considered by the relevant Committees for some time yet.

P

Museum National d' Histoire Naturelle, Paris (MNHN) - Vascular Plants

TAN

Parc de Tsimbazaza

NE

University of New England

MO

Missouri Botanical Garden

K

Royal Botanic Gardens

V

Royal British Columbia Museum - Herbarium

W

Naturhistorisches Museum Wien

E

Royal Botanic Garden Edinburgh

N

Nanjing University

G

Conservatoire et Jardin botaniques de la Ville de Genève

S

Department of Botany, Swedish Museum of Natural History

VI

Mykotektet, National Veterinary Institute

J

University of the Witwatersrand

L

Nationaal Herbarium Nederland, Leiden University branch

Kingdom

Plantae

Phylum

Tracheophyta

Class

Magnoliopsida

Order

Malpighiales

Family

Salicaceae

Genus

Homalium

Loc

Homalium ovatifolium Appleq.

Applequist, Wendy L. 2018
2018
Loc

Blackwellia planiflora Boivin ex

Tul. 1857: 64
1857