Anthurium argyrophyllum Nadruz, Magno & Theofilo 2024, sp. nov.
Creators: name: Coelho, Marcus Alberto Nadruz
name: Magno, Alexandre
name: Valadares, Rodrigo Theófilo
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Alismatales
Araceae
Anthurium
Anthurium argyrophyllum

description: Anthurium argyrophyllum Nadruz, Magno & Theófilo, sp. nov. (Fig. 1)
Anthurium argyrophyllum is very similar to A. cachoeirense Valadares & Sakuragui (2015: 81) but differs in having a leaf blade ovate with an adaxial surface shiny moss green coloured and abaxial surface pale semi-glossy olive-green (vs. leaf blade elliptic to lanceolate with adaxial surface shiny dark green and abaxial surface light green coloured), primary lateral veins 11 to 16 on both sides (vs. 28–31 on both sides), peduncle with 6.6–14.5 cm long, curved in fruiting (vs. peduncle with 23.1–31.1 cm long, spreading in fruiting), spathe with 8.6–17.9 cm long, chartaceous (vs. spathe with 6.2–7.5 cm long, membranaceous) and stigma emergent and purplish (vs. stigma not emergent and greenish).
Type: — BRAZIL. Bahia: Santa Luzia, próximo a fazenda do Sr. Eugenio, 29. I.2019, fl., M. T. C. Lacerda & J. E. Santos 1165 (holotype RB!).
Rupicolous herb, stem up to 30 cm long, erect internodes very short; prophylls and cataphylls 3.0–4.0 cm long, greenish when young, chestnut to straw colored when old, forming a fibrous mass. Leaves not peltate, sheath 2.9–3.1 cm, not ligulate; petiole erect, 7.3–23.5 × 0.55–0.99 cm, petiole:peduncle ratio 2.5:1.0, greenish, U-shaped, flattened to canaliculate adaxially with acute to obtuse margins, rounded abaxially, covered with raphides, without glandular punctations; geniculum 0.9–2.8 × 0.7–0.9 cm, clear matte green when fresh, drying blacker than rest of petiole, flattened to slightly concave with obtuse margins adaxially, rounded abaxially, without glandular punctations; leaf blade erect to spreading, ovate, 41.0–41.8 × 15.8–16.6 cm, chartaceous when fresh and dried, apex acute-acuminate, base obtuse-truncate to obtuse-cordate, adaxial surface shiny moss green colour, with flat greenish margin, without covered with raphides, abaxial surface pale semi-glossy olive-green, drying green-greynish in both faces, without glandular punctations, posterior lobes up to 1.5 cm long, not imbricate, rounded to obtuse at apex, sinus triangular without denudation; midrib greenish and lighter than blade adaxially, flattened at base, rounded to obtuse and prominent at apex adaxially, rounded and prominent abaxially; basal veins absent to 1, reaching the margin up to 1/8 of the length of the leaf blade; primary lateral veins 11 to 16 on both sides, obscured adaxially when fresh, slightly evident and darker than the lamina abaxially when fresh, arched, forming an angle of 30–43° at the junction with the midrib, interprimary veins distinct from primary lateral veins, collective vein arising at the base of the blade or up to 5.0– 6.8 cm above it, 0.8–1.5 cm from the margin. Inflorescence with peduncle greenish, erect up to anthesis, curved in fructification, terete to 1–2 ribbed, 6.6–14.5 × 0.42–0.91 cm, covered with raphides, glandular punctations absent; geniculum absent; spathe flat, ovate, 8.6–17.9 × 3.1–6 cm, chartaceous, greenish to greenish with reddish to vinaceous nuances, not decurrent, acute at apex, erect in pre-anthesis, perpendicular to spreading in anthesis, erect in fructification, pustules absent, both surfaces densely covered with white speckles, forming a obtuse to acute angle with peduncle, decurrent 0.6–1.6 cm long; spadix stipitate, tapered, 3.8–13.7 × 0.76–1.41 cm, light green color pre-anthesis, greenish-purplish in anthesis, gray-brown in post-anthesis, stipite 0.3–1.7 cm long; 7 flowers visible per principal spiral, 11–12 visible per secondary spiral. Flowers rhombic, tepals greenish in pre-anthesis and anthesis, brownish post-anthesis, dorsally acute, internally convex; lateral tepals 1.74–1.85 × 1.79–1.92 mm; anterior/posterior tepals 1.61–1.95 × 1.12–1.14 mm; stamens emerging in a scattered manner, laterals first followed quickly by alternates, filaments flattened, striated, 2.5–2.8 × 1.0– 1.1 mm; anthers ovate, dorsifixed, extrorse, 0.6–0.8 × 0.9 mm; polen yellowish to whitish; pistils purplish, oblong to elliptic, not emergent; stigma emergent, rounded, purplish; ovary bilocular, 3.2–3.5 × 1.3–2.8 mm, 1 ovule per locule, with apical placentation, funicle without trichomes. Infructescence with berries greenish to greenish-purplish at apex, translucent to whitish at base, oblong, 0.6–0.8 × 0.50–0.55 mm; mesocarp mucilaginous with elongate raphides; seeds cream color to yellowish, oblong in outline with convex faces, 0.35–0.40 × 0.23–0.26 mm, with rough surface.
Habitat and distribution: — Anthurium argyrophyllum is a typically rupicolous species with occurrence restricted to rocky outcrops associated with rainforests currently used for cocoa crop (cabruca). Its distribution is restricted to forests located between the Rio Jequitinhonha and the Rio de Contas (Fig. 2), although it has no confirmed records in conservation units, its occurrence is indicated in the Lapão Environmental Protection Area (J. E. Santos pers. comm.). The measured size for the type population is ca. of 600 individuals, including well-established young people.
Conservation status: —The species has little collection effort about the amount of forest fragments between the Rio Jequitinhonha and the Rio de Contas. As a result, the species is considered Data Deficient (DD) according to the International Union for Conservation of Nature (IUCN 2012) until more information is available.
Eponymy: —The specific epithet “argyrophyllum ” is given by the greenish-silver characteristic of the leaf blade.
Phenology: —Flowering in January and October. Infructescence in October.
Paratypes: — BRAZIL. Bahia: Itapebi, fazenda do senhor João Eduardo (cultivated), 01 January 2023, A. Magno & J. E. Santos 01 (VIES!); Santa Luzia, aos arredores da APA do Lapão, 190 m, 07 October 2023, A. Magno & J. E. Santos 18 (VIES!); idem, A. Magno & J. E. Santos 19 (VIES!).
Features and affinities: —Specimens found in nature have predominantly spreading leaves (Fig. 6), but when in cultivation their leaves are erect (Fig. 3–4) and can be confused with Anthurium sagrilloanum Theófilo & T.F.Sagrillo in Valadares et al. (2020: 60) differing from this in having prophylls and cataphylls chestnut to straw colored when old, forming fibrous mass (vs. chestnut or brownish to greenish when old, persistent and entire at stem apex, deciduous at stem base), petiole 2.4–2.6 × larger than the peduncle (vs. usually smaller), basal veins absent to 1 (vs. basal veins 2 to 4), primary lateral veins 11 to 16 on both sides (vs. 14–24 on both sides), peduncle curved in fruiting (Fig. 5) (vs. peduncle spreading in fruiting) spathe flat (vs. naviculate), spadix stipitate and greenish-purplish in anthesis (vs. spadix sessile, purplish in anthesis).
Also noteworthy is its morphological proximity to Anthurium luschnathianum Kunth (1841: 73), distinguished by its erect stem (vs. decumbent stem with erect apex), prophylls and cataphylls forming a fibrous mass when old (vs. little decomposed to deciduous towards the base of the stem), peduncle 6.6–14.5 cm long, curved during fruiting (vs. peduncle 31.5–65.4 cm long, not curved), spathe ovate (vs. spathe lanceolate).
Anthurium argyrophyllum is provisionally included in the Anthurium section Urospadix Engl. because it presents characteristics very close to species with a curved peduncle during fruiting (e.g. A. cleistanthum, A. coriaceum) and is restricted to eastern Brazil. The polymorphism of the base of the leaf blade raises questions about its sectional positioning. For the first author (MANC), the species should be included in a new section comprising all species with leaf blades containing a chordate base and variations. For the third author (RTV) this hypothesis can be supported, but restricted to species with a strictly chordate base and a non-curved peduncle during fruiting (e.g. Anthurium marcusianum Theófilo, L.Kollmann & Sakur. in Valadares et al. (2019: 3), Anthurium augustinum K.Koch & Lauche in Koch (1855: 7), Anthurium xanthophylloides Barroso (1970: 1)). In any case, it is complicated to assume that the evolutionary history of this lineage constitutes a disjunction from the Anthurium section Belolonchium Schott (1860: 528), an argument supported by previous molecular studies (Temponi 2006, Carlsen & Croat 2013).
description: Published as part of Coelho, Marcus Alberto Nadruz, Magno, Alexandre & Valadares, Rodrigo Theófilo, 2024, A new Anthurium (Araceae) species with silver leaves from Bahia Atlantic Forest, Brazil, pp. 69-76 in Phytotaxa 663 (2) on pages 70-74, DOI: 10.11646/phytotaxa.663.2.2, http://zenodo.org/record/14515961