Plukenetia carolis-vegae, Bussmann, Paniagua & C. Tellez, Econ. Bot.

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

19. PLUKENETIA CAROLIS-VEGAE Bussmann, Paniagua & C.Téllez, Econ. Bot. 67 (4): 388. 2013.

TYPE: PERU. Amazonas: Provincia de Rodr´ıguez de Mendoza, Distrito de Limabamba, finca of Sr. Rodr´ ıguez in Monte Alegre , [-6.58547°, -77.53214°], 1854 m, 19 August 2012, R.W. Bussmann, N. Paniagua Zambrana, C. Vega Ocana ~ & R. Arista Melendez 17132 (holotype: HAO (not seen) ; isotypes: MO [sheet 1 of 2; accession 6605775, barcode MO-2822725 ; image!], MO [sheet 2 of 2; accession 6605774, barcode MO-2822724 ; image!] ; INBIAPERU [Instituto para el Desarrollo Local Sostenible y la Conservación Biológica y Cultural Andino-Amazónica, Trujillo]) . [The two isotype sheets at MO could not be found at the time of writing. They are mistakenly labeled as holotypes according to images on Tropicos.org.]

Discussion —Together, P. carolis-vegae , P. ˟ huayllabambana , and our proposed new species 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 squarish-cylindrical column usually <10 mm long, fruits; 3–10 cm in diam with “large” or “extra-large” seeds, and 1–2 thick stipels at their petiole apex.

The two previously described species, P. carolis-vegae and P. ˟ huayllabambana , are geographically and morphologically similar to each other. Both taxa are primarily distributed in the Rodr´ıguez de Mendoza Province in northern Peru ( Fig. 6 ), have large fruits 4–10 cm in diam with “extra-large” seeds, and appear to be fully or semi-domesticated with possible cultivation or reintroduction into forests adjacent to farmland. Plukenetia carolis-vegae differs by having 25–35 stamens with longer filaments, 0.5–1 mm long (perhaps as long as; 1.8 mm, see below), 4 (rarely 5) staminate sepals, and inflorescences densely packed with staminate cymules. By comparison, P. ˟ huayllabambana has 10–15 stamens with shorter filaments, 0.1–0.3 mm long in its type description ( Bussmann et al. 2009) but; 0.5 mm long in an independently measured specimen (Quipuscoa 381 MO), 5 (rarely 4) staminate sepals, and inflorescences loosely packed with staminate cymules.

We hypothesize that P. carolis-vegae is a cultivated species derived from natural populations of our new species P. sylvestris . Presently, P. carolis-vegae is only known from its type collection (Bussmann et al. 17132), which was collected from a farmer’ s field ( Bussmann et al. 2013). It is most clearly distinguished from P. sylvestris by its larger fruits and seeds but otherwise they appear to share the densely packed inflorescences and longer filaments that distinguish both species from P. ˟ huayllabambana (based only on illustrations and photographs from Bussmann et al. 2013; no specimens were available for examination). Based on its description, P. carolis-vegae also differs by having 25–35 stamens and 4 (rarely 5) staminate sepals, compared to 10–18 stamens and regularly 4–5 staminate sepals in P. sylvestris .

Unfortunately, the MO isotype sheets of P. carolis-vegae could not be located at the time of writing, but are needed to conduct better morphological comparisons with P. sylvestris and to review discrepancies with its species description. For instance, the description of P. carolis-vegae characterized its filaments as relatively short, 0.5–1 mm long, and its staminate flowers as lacking nectaries, but the type illustration ( Bussmann et al. 2013, Fig. 1C ) suggests its filaments can be as long as; 1.8 mm and that large irregularly shaped nectary segments are present. Additionally, its stamens were reported as “25–35 ˟ 0.1–0.3 mm in diameter,” which by convention implies a length of 2.5–3.5 cm, surpassing any stamen length observed in Plukenetia . However, Bussmann et al. (2013) also specify that the filaments are 0.5–1 mm long, suggesting there was a typographical error and that 25–35 refers to stamen number and not length. Indeed, the species description of P. ˟ huayllabambana ( Bussmann et al. 2009) uses a similar, although less conventional, format (“stamens 10–14, 0.2–0.4 mm in diameter; filaments flattened, broad, 0.1–0.3 mm long”), which suggests the authors intended to report 25–35 stamens.

Distribution, Habitat, and Phenology —Presently, this species is only known from its type collection from the Amazonas region of northern Peru ( Fig. 6 ). It is a twining liana 4–6 m long, found in cultivation at 1855 m elevation. The type collection contains both flowers and fruits and was collected in August.

Figures

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.