Anthurium zalesskii Popovkin & Nadruz, 2025

Anthurium zalesskii Popovkin & Nadruz , sp. nov. ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 )

Anthurium zalesskii is characterized by having 3–5 leaflets to 12 cm in length, with primary lateral veins weakly impressed on the adaxial surface. Morphologically, it may be confused with A. pentaphyllum , however it differs from the latter in the length of its petiolules (5–7 cm vs. 0.2–1.0 cm in A. zalesskii ), that of leaflets (10–43 cm vs. 9–12 cm in A. zalesskii ), the number of primary lateral veins (8–16 vs. 5–7 in A. zalesskii ), and globose berries (vs. obovoid in A. zalesskii ).

Type:— Brazil. Bahia: Municipality of Entre Rios, Pau de Umbigo , 11° 52’ 44” S ; 38° 02’ 26” W, 150 m, 26 Dec. 2015, Popovkin & Mendes 2143 (holotype RB!) .

Hemiepiphytic, adpressed-climbing, terrestrial, prostrate, when juvenile and not within reach of an attainable support; roots numerous, spreading, whitish, thick and velamentous, villous, 4–5 mm diam; stem erect; clasping roots at ends of internodes, greenish-pink in the upper part of the stem, greenish, with an apex pink to reddish, when young, turning brown; internodes 0.3–0.4 × 5–6 cm, with the shortest towards the stem apex; cataphylls and prophylls entire, falcate, 1.5–2.5 cm long, green when young, becoming castaneous and decomposing as fibers towards the stem apex. Leaves scattered along stem, spreading; petiole 10–22 × 0.2–0.3 cm, longer than leaf blade, narrowly sulcate with obtuse margins adaxially and rounded abaxially; sheath 1.5–3.0 × 0.4–1.0 cm at midpoint, green; geniculum 0.7–1.0 × 0.3–0.4 cm; petiolules 0.2–1.0 cm long, flattened, with a prominent central vein and sharp and sinuous margins adaxially, rounded abaxially; blades palmatisect, semiglossy on both sides; leaflets 3–5 on mature plants, 1–3 on juvenile, elliptic to obovate, 9–12 × 2.5–4.5 cm, moderately bicolor, without glandular punctations on both faces, apex obtuse-acuminate, base obtuse-oblique, lateral leaflets frequently asymmetric, margins undulate when young, straight (entire) when adult; midrib acute adaxially, more prominently acute abaxially; primary lateral veins 5–7 per side, departing midrib at 45° angle, weakly sunken and impressed adaxially, weakly prominent and acute abaxially; tertiary veins similar; collective veins arising from the base, 0.3–0.5 cm from the margin. Inflorescence erect, shorter than the leaves; peduncle reddish brown, 7–8 × 0.5–0.6 cm, shorter than petiole, terete, striate; spathe green, with margins tinged purple, obovoid at base, cordate, 6–9 × 4–6 cm, acuminate at the apex, clasping at the base, coriaceous, erect before anthesis, base meeting peduncle at 180°, reflexing and turning backward afterwards; spadix erect, sessile, green when young, turning purple towards anthesis, brownish after, slightly tapered, 4.2–8.1 cm long, 1.4 cm diam. at base; 6 flowers per principal spiral, 8 per secondary spiral; flowers rhombic, 0.36–0.37 × 0.32–0.33 cm, stamens visible just above the tepals at anthesis; pistil bilocular; 1 ovule per locule, axial subapical placentation, funicle papillate. Infructescence reflexed, 4.2–8.1 × 0.8–1.2 cm; spathe persisting in infructescence, reflexed-spreading; berries obovoid, bicolor, apex rounded, dark vinaceous at apex, red towards the base, 0.9 × 0.3–0.9 cm, hanging on threadlike colorless tepal fibers when completely ripe; seeds dark vinaceous, 0.4–0.6 × 0.1–0.3 cm, smooth.

Phenology: — The species was found in post-anthesis and in fruit during December 2015.

Eponymy: — The eponym of the specific epithet refers to Dmitrii Mikhailovich Zalessky [Дмитрий Михайлович Залесский, 1910–1987] ( Zalesskiy 2013), Director (1946–1981) of the Botanical Garden of the St Petersburg State University, St Petersburg, Russia, who was instrumental in inspiring the first author, though only in advanced years of latter’s life, in the study of tropical plants.

Distribution: — Anthurium zalesskii is endemic to the Atlantic Forest of the northern littoral zone of Bahia, Brazil ( Fig. 1 View FIGURE 1 ). It is presently known only from the type collection and in cultivation by the first author.

Habitat and ecology: — The species is an adpressed-climbing hemiepiphyte, terrestrial, prostrate, foraging ( Ray, 1992), when juvenile and not within reach of attainable support. It is found in an Open Ombrophilous Forest ( Velloso et al. 1991), with an average tree height of 5–7 m and with sun rays frequently reaching the underbrush.

Conservation status: — The area suffers from the native habitat loss due to the expansion of mono-silviculture (mostly Eucalyptus plantations), agriculture, cattle raising, and settlement, which have severely fragmented its native Atlantic Forest original cover, with only forest patches of differing sizes remaining, mostly in conservation areas protected by law ( Diário Oficial 2006, May et al. 2015).

Per Table 2.1 in the IUCN Red List Categories and Criteria, with an EOO of <100 km 2 (B1), an AOO of <10 km 2 (B2), and the number of mature individuals <50 (C2ai D), combined with plausibility of population loss owing to climate change and other threats (D2), we rank this new species as Critically Endangered (CR).

Additional specimen examined (paratypes): — Brazil, Bahia: Entre Rios, localidade Pau de Umbigo, 11°52’44’’S 38°02’26’’W, 5 Nov. 2023, fl., Popovkin & Mendes 2180 (CEPEC!, HUEFS!)

Discussion: — Anthurium zalesskii belongs to A. sect. Dactylophyllium , as delimited by Croat & Carlsen (2013), with palmatisect leaf blades and leaflets divided to the base.

The new species is similar to A. pentaphyllum , but the latter differs from it by the number of leaflets (5–12 vs. 3–5 in A. zalesskii ), petiolules size (5–7 vs. 0.2–1.0 cm in A. zalesskii ) and leaflet length (10–43 cm vs. 9–12 cm in A. zalesskii ), number of primary lateral veins (8–16 vs. 5–7 in A. zalesskii ), and globose (vs. obovoid in A. zalesskii ) berries. A. pentaphyllum is also found in the Ombrophilous Dense Forest, with trees frequently reaching heights of 20–30 m, whereas A. zalesskii is limited to the Ombrophilous Open Forest, with the average tree height of 5–7 m and where sun rays frequently reach the underbrush.