Picramnia vinacea Londoño-Ech. & A.M.Trujillo, 2023

Londoño-Echeverri, Yeison & Trujillo-López, Ana María, 2023, Taxonomic studies in Colombian Picramniaceae (Picramniales): new species of Aenigmanu, Nothotalisia and Picramnia from the Pacific and Magdalena Valley regions, Phytotaxa 622 (5), pp. 281-297 : 291-295

Picramnia vinacea Londoño-Ech. & A.M.Trujillo , sp. nov. ( Figs 6–8 )

Type:— COLOMBIA. Antioquia: Mun. Maceo, DRMI del Río Alicante, vereda Santa Barbara, cerca a los predios de la Hacienda Santa Barbara, unidad agrícola familiar número 10, 462 m, 6°32ʹ57.69ʹʹN, 74°37ʹ28.90ʹʹW, 19 Dec 2021 (♀ fl & fr), Trujillo et al. 309 (holotype: HUA!; isotype: MEDEL!) .

Picramnia vinacea can be distinguished from P. magnifolia Macbride (1934: 376) by its racemose staminate and pistillate inflorescences, i.e., bearing solitary flowers (vs. inflorescence in thyrses, bearing congested glomerules), staminate flowers with shorter pedicels 3.0– 3.7 mm long (vs. 4.0–8.0 mm), stamens shorter than petals, filaments 1.0– 1.1 mm long (vs. stamens longer than petals, filaments longer than 3 mm) and fruits glabrous (vs. pilose to glabrescent).

Shrub or tree 2–6 m tall, indumentum of simple trichomes, buds and young branchlets densely shortly strigose to puberulous, glabrescent. Leaves imparipinnate, 9–15-foliolate, alternate, petiole (3.6–) 5.6–8.7 cm long, terete, basally pulvinate, sparsely shortly strigose to puberulous, pulvinus irregular (i.e., not terete), rachis (13.6–) 17.2–26.7 cm long, terete, sparsely shortly strigose to puberulous, petiolule 3–5 mm long, shortly strigose to puberulous; leaflets largest toward leaf apex; blades 3.5–18.0 (–22.7) × 1.8–7.6 cm, ovate to elliptic (slightly oblong), basally obtuse to acute and rounded, truncate or cuneate, apically acute and acuminate, glabrous on both surfaces, verruculose, more noticeably adaxially, dark vinaceous when dry (only specimens preserved with ethanol before drying were observed); primary vein raised abaxially, impressed adaxially, secondary veins 5–8 on each side, raised abaxially, flat to slightly impressed adaxially, eucamptodromous becoming brochidodromous distally, tertiary veins raised abaxially, flat adaxially, usually percurrent; margin entire. Inflorescences simple racemes, cauline, pendulous, 7.6–26 cm long, axes terete, peduncle obsolete; staminate racemes ca. 12.1 cm long, shortly strigose to puberulous, bearing ca. 88 flowers or pedicel scars, bracts ca. 0.5 × 0.5 mm, ovate, shortly strigose to puberulous abaxially, glabrous adaxially, margin entire, pedicel 3.0– 3.7 mm long, terete, shortly strigose to puberulous, bracteoles 2, ca. 0.1 × 0.1 mm, at base of pedicel, shortly strigose to puberulous abaxially, glabrous adaxially, margin entire; pistillate racemes 7.6–26.0 cm long, shortly strigose to puberulous more densely towards the pedicel insertion, bearing 42–84 flowers or pedicel scars, bracts ca. 0.5 × 0.5 mm, ovate, shortly strigose to puberulous abaxially, glabrous adaxially, margin entire, pedicel 0.8–1.1 mm long (fruiting pedicel 2–5 mm long), terete, densely shortly strigose to densely puberulous, bracteoles 2, ca. 0.1 × 0.1 mm, at base of pedicel, shortly strigose to puberulous abaxially, glabrous adaxially, margin entire. Flowers pentamerous, staminate larger than the pistillate, calyx and corolla magenta in vivo; staminate flowers with sepals 0.8–0.9 × 0.5–0.7 mm, elliptic, ovate to obovate, apically acute to obtuse and cuneate or rounded-acuminate, sparsely strigose abaxially, glabrous adaxially, revolute apically, margin membranous-hyaline, entire; petals 1.5–1.7 × 0.3–0.4 mm, linear to narrowly oblanceolate, apically acute to slightly obtuse and cuneate to rounded, glabrous, margin entire; stamens 5, exerted, filaments 1.0–1.1 × 0.1–0.2 mm, linear, flat, slightly wider basally, minutely papillose, anthers 0.2 × 0.2–0.3 mm, orbiculate, anther connectives densely papillate, gynophore ca. 0.1 mm tall bearing 5 nectaries, each 0.1 × 0.1 mm, alternating with stamens, pistillodium 0.5 × 0.4–0.5 mm, densely villous; pistillate flowers with sepals 0.5 × 0.4–0.5 mm, ovate, apically acute to obtuse and cuneate to broadly acuminate, sparsely strigose abaxially, glabrous adaxially, margin membranous-hyaline, entire; petals 1.0–1.1 × 0.2–0.3 mm, linear to narrowly oblanceolate, apically acute to slightly obtuse and rounded, glabrous, margin entire; staminodes absent, disc ca. 0.1 × 0.6 mm, intrastaminal, like a gynophore (i.e., not annular, rather subtending the ovary), sparsely villous, nectaries 5, each ca. 0.1 × 0.1 mm, alternating with petals, ovary ca. 0.7 × 0.7 mm, spheroid, glabrous or sparsely villous, style obsolete, stigma bilobed, glabrous, each lobe ca. 0.5 × 0.1 mm, recurved, minutely papillate. Fruits 1.1–2.3 × 0.8–1.3 cm, ellipsoid, glabrous, yellow to red when immature becoming dark violet at maturity in vivo, surface smooth, pericarp ca. 0.2 mm thick. Seeds 1, ca. 1.0–1.9 × 0.7–1.0 cm, ellipsoid, testa reddish in sicco, glabrous, cotyledons indistinct, surface coarsely verrucose to wrinkled.

Distribution and habitat:— Endemic to Colombia, recorded only from Antioquia Department, specifically the municipalities of Maceo, Puerto Nare, San Carlos, and Sonsón ( Fig. 3 ), in the Magdalena Valley Biogeographical Region, in the understory of karst areas, equatorial rainforest climate type (Af), 200– 555 m.

Phenology:— Flowering September and December, fruiting February, October and December.

Etymology:— Referring to the vinaceous (wine coloured) leaflets when dry, a useful distinguishing feature of this species.

Conservation status:— Known from three subpopulations, two of these partially inside protected areas, resulting in four locations with AOO = 28 km 2 and EOO = 316 km 2. These forests are small (<100 km 2), fragmented and surrounded by extensive, continuously expanding livestock farms. Of the two partially protected subpopulations, one is partially inside a large planned hydroelectrical project and the other a mining project (mining of calcareous rock), paradoxically inside the protected area. The subpopulation outside the protected areas is also partially inside a mining area; all subpopulations are less than 25 km from populated centres. The suggested category for P. vinacea is endangered, EN according to criteria B1ab(iii)+2ab(iii), due to its small and restricted distribution, poor quality habitat, apparent karst requirements and current threats, including high rates of deforestation in the Magdalena River Valley ( Sanchez-Cuervo & Aide 2013).

Additional specimens examined:— COLOMBIA. Antioquia: Mun.Maceo, Corregimiento La Susana, alrededores del río Cupiná , cerro Mauro y cerro El Desquite , 556 m, 6°37ʹ17.79ʹʹN, 74°38ʹ5.63ʹʹW, 24 Oct 2020 (st), Londoño et al. 738 ( HUA) ; Mun. Puerto Nare: vereda Cominales ( Narices ), mina Piedras Claras , 200–500 m, 6°11ʹ0ʹʹN, 74°45ʹ0ʹʹW, 3–13 Sep 2010 (♁fl), Montoya & Restrepo 17 ( HUA) ; vereda Tambores, quebrada Los Yules , 400 m, 6°9ʹ53.43ʹʹN, 74°47ʹ33.41ʹʹW, 4 Oct 2012 (fr), Velásquez 6867 ( HUA) ; Mun. San Carlos: quebrada Peñol Grande , 448 m, [6°11ʹ45.91ʹʹN, 74°47ʹ38.28ʹʹW], 9 May 2013 (st), Jiménez 211 ( HUA) ; Mun. Sonsón: concesión de cementos Río Claro, bosque sobre rocas Calcáreas , 5°53ʹ0ʹʹN, 74°51ʹ0ʹʹW, 18 May 1990 (♀ fl), Cogollo & Cárdenas 4478 ( COL, JAUM) ; jurisdicción de Cementos Argos, sector Caño Feo al frente de la planta de Argos, 450 m, 5°51ʹ16.7ʹʹN, 74°51ʹ21ʹʹW, 25 Feb 2012 (fr), David et al. 4043 ( HUA) .

Notes:— Picramnia vinacea shares with P. magnifolia fistulose stems, cauline inflorescences and pentamerous calyx. The vinaceous leaflets of P. vinacea are distinctive and useful for recognising it at first glance, but this feature is not unique and is present in some other species with darkly drying leaflets, e.g., the type specimen of P. sellowii subsp. spruceana ( Engler 1874: 238) Pirani (1990: 132) and even some specimens of P. magnifolia , although not in the type specimen.

In addition to darkly drying leaflets of Picramnia sellowii subsp. spruceana , P. sellowii Planchon (1846: 578) sensu lato also have pentamerous calyx, exerted stamens, bilobed stigmas and glabrous to sparsely puberulent fruits ( Pirani 1990, Thomas 1990), features shared with P. vinacea . However, its solid stems (vs. fistulose in P. vinacea ), leaflet blades usually with indument at least on the midvein (vs. completely glabrous), and terminal and forked inflorescences with the staminate ones bearing cymules or dense glomerules (vs. cauline and simple racemose, staminate flowers solitary) distinguish it from the new species.

The large leaflets and cauline inflorescences of Picramnia vinacea also resemble P. latifolia Tulasne (1847: 258) , from which it can be distinguished by its darkly vinaceous drying leaflets (vs. olive green), fistulose stems (vs. solid), racemose staminate inflorescence (vs. thyrses, i.e., racemes bearing 1–3-flowered cymules), staminate flowers with longer pedicels 3.0– 3.7 mm long (vs. up to 2.0 mm), stamens shorter than petals, filaments 1.0– 1.1 mm long (vs. stamens longer than petals, filaments equal or longer than 1.9 mm) and pistillate flowers with ovary glabrous to sparsely villous (vs. densely puberulous).

Other species with pentamerous calyx in or near Colombia have minor degrees of resemblance with P. vinacea : P. caracasana Engler (1874: 236) , P.gracilis Tulasne (1847: 260) , P.pentandra Swartz(1797: 220) , P. polyantha (Bentham 1840: 60) Planchon (1846: 577) and P. sphaerocarpa Planchon (1846: 578) . These species can be distinguished from the new species by their remarkably pubescent leaflets at least on the primary vein abaxially (not in P. pentandra ), terminal to subterminal inflorescences (remarkably forked in P. pentandra and P. polyantha ) and both staminate and pistillate thyrses, i.e., bearing cymules or glomerules.

The protologue of Picramnia apetala Tulasne (1847: 264) noted a pentamerous calyx but included several features different from those of P. vinacea : leaftet primary vein pubescent, staminate inflorescences in thyrses, terminal to subterminal, and no corolla, the latter an unusual feature also reported for few Brazilian species by Pirani (1990). Although no digitalised type specimens were found at P, the isotype at F clearly show the leaflet pubescence, which along with the protologue distinguishes P. apetala from P. vinacea .

Figures

FIGURE 3. Distribution of Aenigmanu chococola, Nothotalisia karsticola and Picramnia vinacea.

FIGURE 6. Photographs of habitat (A–B) and live plants of Nothotalisia karsticola (C–E) and Picramnia vinacea (F–I). A. Habitat at landscape-scale. B. Understory habitat. C. Leaf of pistillate plant. D. Fruiting branchlet of pistillate plant. E. Immature but fully expanded fruit. F. Mature branchlet of pistillate plant. G. Fruiting raceme. H. Fruit details. I. Open fruit with one seed. (A–B, from the type locality of N. karsticola and P. vinacea; C–E, from Londoño et al. 1022; F–I from David et al. 4043; composed by Ana Cristina Pareja, HUA. A. by Jorge Pérez (MEDEL); B, D–E by A.M. Trujillo; C by Y. Londoño, F–I by Heriberto David, HUA).

FIGURE 7. Holotype of Picramnia vinacea.

FIGURE 8. Picramnia vinacea. A. Mature branchlet of pistillate plant. B. Staminate raceme. C. Staminate flowers. D. Pistillate raceme. E. Pistillate flowers. F. Details of staminate flower. G. Details of pistillate flower. H. Fruiting raceme. (A from the isotype; B–C, F from Montoya & Restrepo 17; D–E, G–H from the holotype; drawing by Ana Cristina Pareja, HUA).