Plukenetia huayllabambana, Bussmann, C. Tellez & A. Glenn

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 : 529-530

20. PLUKENETIA ˟ HUAYLLABAMBANA Bussmann, C.Téllez & A.Glenn, Nordic J. Bot. 27 (4): 313. 2009 .

TYPE: PERU. Región Amazonas: Provincia de Rodr´ıguez de Mendoza, El Cedro-Cruzpata , [-6.404°, -77.449°], 1676 m, 5 July 2008, C. Téllez, C. Vega & L. Cabrera 02 (holotype: INBIAPERU [Instituto para el Desarrollo Local Sostenible y la Conservación Biológica y Cultural Andino-Amazónica, Trujillo] ; isotype: K [barcode K001089689 ; image!]) . [The isotype was originally published as housed at MO ( Bussmann et al. 2009), but only one sheet of a different collection (Téllez et al. 004, MO! [accession 6116702, barcode MO-2255093]) incorrectly labeled as an isotype could be found. The isotype has since resurfaced at Kew (Téllez et al. 02, K [barcode K001089689; image!]) and it appears to be the isotype that was originally deposited at MO (“Ex Herbarium” MO [accession 6116701]).]

Discussion — Plukenetia ˟ huayllabambana , along with P. carolis-vegae and P. sylvestris , form a high elevation species complex sister to P. volubilis . Members of the species complex grow in high elevation montane rainforest in the Andes, 1280–2440 m, and possess staminate flowers with large irregularly shaped interstaminal nectary segments, short styles partly connate into a cylindrical column usually <10 mm long, and 1–2 thick stipels at their petiole apex. Members of the species complex also have larger fruits and seeds, fruits 4–10 cm in diam with “extra-large” seeds in P. ˟ huayllabambana and P. carolis-vegae , and fruits 2.8–3.7 cm in diam with “large” seeds in P. sylvestris (similar in size to P. volubilis but with larger seed volume; Cardinal-McTeague et al. 2019a).

This species is a putative hybrid between P. sylvestris ˟ P. volubilis, which is supported by the presence of a P. volubilis plastid genome in accessions of P. ˟ huayllabambana ( Cardinal-McTeague et al. 2019a, Fig. S3 ) and their intermediate staminate floral morphology. Both P. ˟ huayllabambana and P. volubilis have stamens with short filaments,; 0.5 mm long, compared to longer filaments,; 0.5–1.4 mm long, in P. sylvestris . Staminate sepal number also appears to differ, more frequently with 5 (rarely 4) sepals in P. ˟ huayllabambana and, regularly varying from 4–5 sepals in P. sylvestris , and with 4 sepals in P. volubilis .

Plukenetia ˟ huayllabambana is distributed in the Amazonas and Cajamarca Regions of northern Peru ( Fig. 6 ). It is known from only a few collections across three districts but is possibly more common in cultivation. Its staminate flowers were originally described as having filaments 0.1–0.3 mm long and [nectary] disc absent ( Bussmann et al. 2009), but our observations found filaments; 0.5 mm long and large irregularly shaped interstaminal nectary segments to be present (Quipuscoa 381 MO). The original type illustration shows an immature staminate flower dissected from a bud, whereas the staminate flower at anthesis is aberrant and likely from a non-euphorb species ( Bussmann et al. 2009, Figs. 1J and 1H , respectively).

Specimens Examined — Peru. — AMAZONAS: Chachapoyas District, Distrito Leymebamba [sic], Los Chichos / San Lucas , [-6.701°, -77.586°], 2150 m, 19 June 2000, Gruhn et al. 84 ( MO [accession 6406258, barcode MO-2695407 ; seeds: accession 5451714, barcode MO-2695406 ]) ; Rodriguez de Mendoza District, Michina , [-6.378°, -77.527°], 1608 m, 5 June 2008, Téllez et al. 004 ( MO [accession 6116702, barcode MO-2255093 ]) ; Rodriguez de Mendoza District, Quebrada Seca , [-6.378°, -77.527°], 1608 m, 5 June 2008, Téllez et al. 006 ( NY [barcode 02200737; image]) . — CAJAMARCA: San Ignacio, Distrito San José de Lourdes, Villarrica , Nororiental del Maranón ~ RENOM,[-4.917°, -78.833°], 1200–1420 m, 28 October 1995, Quipuscoa 381 ( MO [5294603, barcode MO-302027 ]) .

Figures

FIG. 3. Representative pistillate flower diversity of Plukenetia and its sister genus Romanoa. A. Romanoa tamnoides (Krapovickas & Schinini 36265 MO), styles 70–80% connate into a cylindrical column.B.P.sect. Fragariopsis: P.serrata (Davidse et al.10480 MO), styles entirely connate into an obovoid column.C–F.P.sect. Penninerviae: C. P.brachybotrya (Fuentes et al.5398 MO) and D. P.verrucosa (Prance et al.11255 DAV), styles entirely connate into a globose column; E. P.loretensis (Silva et al. 4750 MO), styles entirely connate into a slender-cylindrical column, dilated at the apex; F. P. penninervia (Wallnöfer et al. 5996 MO), styles entirely connateinto a stout-cylindrical column.G–K.P.sect.Plukenetia: G.P.polyadenia (Aulestia & Grefa 230 MO),H.P.stipellata (Cardinal-McTeague 8 CAN),I.P.volubilis (Wurdack s.n. US), and J. P. sylvestris (Woykowski 6670 MO), styles 70–95% connate into a cylindrical column; K. P. lehmanniana (Rangel et al. 5734 MO), styles 20–25% connate into a cylindrical column,free style arms 2-fid nearthe tips.L.P.sect.Angostylidium: P.conophora(Thomas 5455 MO),styles 75–(90)% connate into a funnel-shaped column,free style arms conspicuously dilated and spreading.M.P. sect.Hedraiostylus: P. corniculata (Brink 5771 L), styles entirely connate into a depressed-globose column with cross-shaped stigmas. N–O. P. sect. Madagascarienses: N. P. ankaranensis (Gillespie 4076 CAN), styles entirely connate into an obconic or obovoid column; O. P. madagascariensis (Andrianjafy et al. 1648 MO), styles 55–60% connate into a cylindrical column, free style arms slender and tapered. Photos A–C, E–H, J–L by W. Cardinal-McTeague, I by K. Wurdack, N by L. Gillespie, O by P. Phillipson. Line drawings: D by Cathy Pasquale, K by Anita Walsmit Sachs, used with permission from Naturalis Biodiversity Center, Leiden, Netherlands. (Scale bars = 1 mm).

FIG. 6. Distribution map of our new species in sect. Penninerviae, P. brevistyla, P. chocoensis, and P. megastyla, and members of the high elevation species complex in sect. Plukenetia, P. carolis-vegae, P. ˟huayllabambana, and P. sylvestris. (Map data ©2019 Google, Imagery ©2019 NASA, TerraMetrics).

FIG.1. Summary cladogram of the relationships recovered by Bayesian analysis of combined and partitioned ETS,ITS, KEA1 introns 11 and 17, TEB exon 17, matK, and ndhF DNA sequence data of Plukenetia and Romanoa (modified from Cardinal-McTeague et al. 2019a), highlighting our revised sectional classification of Plukenetia. Maximum parsimony bootstrap percentage (MPBP) and Bayesian posterior probability (BPP) support values> 50% are indicated on each branch. Branches in bold indicate strong support ($ 85 MPBP and $ 0.95 BPP). Subclade numbering system (P1–P5) follows Cardinal-McTeague and Gillespie (2016). Sections in the pinnately veined clade (P1 + P2) are indicated by light grey boxes,sections in the palmately veined clade (P3–P5) by dark grey boxes; new species are indicated in bold. A–B. Leaf clearings demonstrating leaf architecture (images from Gillespie 1993). A. P. stipellata, Gillespie 413 US. B.P. supraglandulosa, Granville 3626 CAY.C–D. Scanning electron micrographs demonstrating pollen tectum morphology (images from Gillespie 1994). C. P. stipellata, Gillespie 418 DAV. D. P. loretensis, Maguire & Politi 27371 US.