Plukenetia corniculata, Sm.

Cardinal-McTeague, Warren M. & Gillespie, Lynn J., 2020, A Revised Sectional Classification of Plukenetia L. (Euphorbiaceae, Acalyphoideae) with Four New Species from South America, Systematic Botany (Basel, Switzerland) 45 (3), pp. 507-536 : 517-518

4. PLUKENETIA CORNICULATA Sm. , Nova Acta Regiae Soc. Sci. Upsal. 6: 4. 1799.

Pterococcus glaberrimus Hassk. , Flora 25 (2): 41. 1842.

Hedraiostylus glaberrimus (Hassk.) Hassk., Tijdschr. Natuurl. Gesch. Physiol. 10: 141. 1843.

Hedraiostylus corniculatus (Sm.) Hassk., Cat. Hort. Bot. Bogor. 234. 1844.

Sajorium corniculatum (Sm.) D.Dietr., Syn. Pl. 5: 331. 1852.

Sajorium corniculatum (Sm.) Baill., Étude Euphorb. 484. 1858, nom. illeg.

Pterococcus corniculatus (Sm.) Pax & K.Hoffm. in A.Engler (ed.), Pflanzenr. IV, 147, IX (Heft 68): 22. 1919.

TYPE: INDONESIA. Amboina, Bagulae Regione , Illustration t.79, Fig. 2 in Rumphius, Herb. Amboin. 1: 193. 1750 .

Notes —See Gillespie (2007) for species description.

Taxonomic Discussion — Plukenetia corniculata is one of the oldest names in Plukenetia and has a complicated taxonomic history. Originally described as the pre-Linnaean Sajor volubilis ( Rumphius 1750) , it was included as a synonym of Plukenetia volubilis by Linnaeus (1753). Smith (1799) gave Rumphius’ species its first legitimate name, P. corniculata , but four other genera would be erected for Sajor: Pterococcus ( Hasskarl 1842) , Hedariostylus ( Hasskarl 1843), Sajorium ( Endlicher 1843) , and Ceratococcus ( Meisner 1843) . Hasskarl’ s first name, Pterococcus (1842), was previously published by Pallas (1773) in Polygonaceae , so he proposed the replacement name Hedraiostylus in; September 1843 ( Stafleu and Cowan 1979). Subsequent replacement names Sajorium and Ceratoccocus, both nomenclaturally superfluous, were published in October and 2–4 November of 1843, respectively ( Stafleu and Cowan 1976, 1981).

Baillon (1858) first treated Hedraiostylus as a section of the illegitimate genus Sajorium [= Plukenetia ], giving Hedraiostylus priority as a sectional name. The fact that Sajorium was illegitimate precludes the rejection of sect. Hedraiostylus in favour of the autonym Sajorium sect. Sajorium (ICN 2017, Art. 22.5; Turland et al. 2018). When Müller created the first sectional classification of Plukenetia he initially erected sect. Sajor ( Müller 1865), but quickly updated it to sect. Hedraiostylus ( Müller 1866) . To complicate matters, Pterococcus Hassk. was conserved over Pterococcus Pall. , but as a sectional name, Hedraiostylus retains priority.

Figures

FIG. 2. Representative staminate flower diversity of Plukenetia and its sister genus Romanoa. A. Romanoa tamnoides (Krapovickas & Schinini 36265 MO), stamens with slender-cylindrical filaments.B.P.sect.Fragariopsis:P.serrata(Davidse etal.10480 MO),anthers sessileand looselypackedon alarge globosereceptacle.C–E.P.sect.Penninerviae: C.P.loretensis (Freitas et al.155 MO),anthers sessile and densely packed on a small globose receptacle;D.P.penninervia (vander Werff et al.3173 MO),and E.P.supraglandulosa (Granville 3626CAY,US),mostanthers sessile and densely packedon a smallglobose receptacle,witha dimorphicouter whorl of;4 stamenswith filaments,and often witha 4-lobed annular nectary. F–I. P. sect.Plukenetia: F. P. polyadenia (Croat et al.20285 MO), stamens with slender-cylindrical filaments and ligulate interstaminal nectaries; G. P. stipellata (Cardinal-McTeague 8 CAN),stamens withslender-cylindrical filaments and small irregularlyshaped interstaminal nectary segments;H.P.sylvestris (Woytkowski 6670 MO), stamens with slender filaments and large irregularly shaped interstaminal nectary segments;I. P. volubilis (Wurdack s.n.US), stamens with short-conical filaments.J.P. sect.Angostylidium: P.conophora (Avio et al.1621 MO), stamens with short-conical filaments and slender-cylindrical interstaminal nectaries (in pink). K. P.sect.Hedraiostylus: P.corniculata(ChinSee Chung 2712L),stamenswith short-conicalfilaments (sometimes appearingsessile).L.P.sect.Madagascarienses:P.madagascariensis(Villiers et al.4889 MO), anthers more or less sessile,denselyto somewhatloosely packedon an elongatereceptacle.PhotosA–D,F–H,J,Lby W.Cardinal-McTeague;IbyK.Wurdack.Line drawings: E by Alice Tangerini,K byAnitaWalsmit Sachs,used with permissionfrom the NaturalisBiodiversity Center,Leiden,Netherlands.(Abbreviations:an =annularnectary;d= dimorphic filamentous stamens; in = interstaminal nectaries; r = receptacle. Scale bars = 1 mm).