Neurolaena curtipalea V.R.Bueno, Gostel & G.Heiden, 2023

Bueno, Vinicius R., Gostel, Morgan R. & Heiden, Gustavo, 2023, An updated synopsis of Neurolaena (Neurolaeneae, Asteraceae) with a new species from the Colombian Andes, Phytotaxa 622 (2), pp. 131-145 : 140-143

2.2.4. Neurolaena curtipalea V.R.Bueno, Gostel & G.Heiden , sp. nov. ( Figs. 2 , 3 , 4 , 5 ).

Type:— COLOMBIA. Antioquia: Yarumal: Vereda El Cedro , sobre la vía Ventanas-El Cedro , kms. 1–9, elev. 1,710–1,900 m a.s.l., 7º15’N, 75º30’W, 23 March 1988, R. Callejas, F.J. Roldán, A.L. Arbeláez 6213 (holotype NY! without barcode) .

Neurolaena curtipalea resembles N. lobata ; however, it differs from the latter by the apical pair of leaves opposite (vs. alternate), leaf venation eucamptodromous (vs. penninervous), capitula radiate (vs. discoid), involucres 5-seriate (vs. 6-seriate), paleae longer (vs. shorter) than corolla disc, and disc florets with white (vs. yellow) corolla.

Description:—Shrubs 1 m tall; stems cylindrical, striate, sparsely pilose to sparsely hirsute, castaneous, internodes 13.38–18.97 cm long. Leaves mostly alternate, opposite only at stem apex, petiole 5.82–8.92 mm long, blades 8.7– 25.35 × 3.21–15.22 cm, wide elliptic to lanceolate, base attenuate, apex attenuate, venation eucamptodromous; margin serrulate, teeth 0.5–2.4 mm long, 6–14, since middle to apex or entire margins in opposite leaves, ca. 100 teeth, along the margins in alternate leaves, flat; abaxial surface sparsely pilose, eglandular, adaxial surface sparsely strigose, eglandular; membranous, slightly discolorous, abaxial surface dark green, adaxial surface green. Capitulescence paniculiform, densely branched, branching fourth to fifth order ramifications, axis ca. 15 cm long; peduncle 0.65–2.5 mm long, sparsely hirsute, eglandular. Capitulum heterogamous, radiate; involucre 6.1–6.5 × 5.5–6.5 mm, wider than longer or equal, cylindrical to narrowly campanulate. Phyllaries 5-seriate, eglandular, margins entire, flat, scarious, pale yellow, conspicuously striate; outermost series of phyllaries apex acute, sparsely pilose, first series of phyllaries blade 1.75–3.8 × 0.5–0.9 mm, ovate, margins densely ciliate, 3-striate; second series blade 3.5–3.8 × 1–1.1 mm, oblong, margins sparsely ciliate, 3–4-striate; third series blade 4.5 × 1 mm, oblong-elliptic, margins sparsely ciliate, 6–7-striate; innermost series apex obtuse, glabrous, fourth series blade 5.35–5.7 × 0.8–1.15 mm, oblong-elliptic, margins sparsely ciliate, 8-striate; fifth series blade 5.5–6.4 × 1.35–1.5 mm, oblong, margins densely ciliate, 8–10-striate. Receptacle convex, holopaleaceous, paleae 3.3–3.45 × 0.7–0.8 mm, shorter than disc corolla, lanceolate to narrow oblong, apex trifid, concave, glabrous. Ray florets 6–8, pistillate, corolla 6.7–7.6 mm long, liguliform, tube 2.8–3.4 mm long, limb 3.9–4.2 × 1.5–2.2 mm, oblong-elliptic, apex 3-lobulate, 7–8-veined, glabrous, white; style arms 0.9–1 mm long, linear, yellow. Disc florets 40–50, bisexual, corolla 5–5.6 mm long, tubular, tube 1.8–2.1 mm long, lobes 0.35–0.6 mm long, flat, sparsely puberulous to glabrous, white; anthers 1.7–2.2 mm long, light yellow, apical anther appendages deltoid; style arms 0.5–0.8 mm long, linear, yellow. Ovary 0.95–1.2 mm long, glabrous; pappus 25–35 bristles, monotypic, polylength, free, uniseriate, shorter bristle 1.2–4 mm long, medium bristle 2.5–4.4 mm long, longer bristle 4.2–6 mm long, linear, apex long acuminate, margins entire, sparsely erose.

Distribution and Habitat:— Neurolaena curtipalea occurs only in Yarumal, Antioquia, in the central northwestern part of Colombia ( Fig. 2 , 3 , 5 ). This new species can be considered stenoendemic, as it grows in the Altos de Ventanas region among wet groves from elevations between 1,700 to 1,900 m above sea level. Similar to several species of Neurolaena ( Turner 1982) , the occurrence of this new species is restricted to montane rainforest environments. The Alto de Ventanas region encompasses the municipalities of Briceño, Valdivia, and Yarumal within Corantioquia, Antioquia Department, Colombia ( Correa 2006). This region lies on the western side from the north range of the Andean Central Cordillera ( Correa 2006), and is characterized by a mountainous landscape, elevations from 1,300 to 2,200 m., annual precipitation reaching 4,000 mm ( Correa 2006), and extreme humidity due the persistent fog ( Gomez 1994).

This region contains the highest amount of endemic and threatened species in the Antioquia Department ( Rainforest Trust 2023), such as rare magnolias ( Cardenas & Salinas 2007), orchids ( Luer & Escobar 1983, 1984 a, 1984b, 1984 c, 1984d; Vieira-Uribe & Moreno 2019), and birds ( Cuervo et al. 2008). This high biodiversity found in the area is due to the Panama isthmus and Andes orogeny and current edaphoclimatic conditions, favoring a biogeographical meeting point where North and Central American lineages ( Cuervo et al. 2008) meet South American lineages. Despite the high biodiversity of this region (Luer & Escobar 1984, 1984a, 1984b, 1984c, Vieira-Uribe & Moreno 2019), there is no checklist for the flora nor other articles highlighting the species of Asteraceae found in this region.

Conservation:— Neurolaena curtipalea was found in a unique locality: Vereda El Cedro on the way to Ventanas. According to the geographical coordinates of the collecting site, this specimen was collected in a region that is now part of the Parque Nacional Natural Paramillo (Natural Paramillo National Park). Even though it is in a protected area, the species is likely threatened by deforestation that destroys many areas in the region and threatens the region’s conservation ( Rainforest Trust 2023). Most of the Neurolaena species, with the exception of N. lobata , occur in mountainous, isolated places and in small populations ( Turner 1982); probably, the same pattern is seen in N. curtipalea . More fieldwork is needed to generate new collection records of this species and facilitate the formal assessment of its Conservation Status ( IUCN 2022).

Etymology:—The epithet “ curtipalea ” refers to the paleae shorter than the corolla of the disc florets. This new species has the smallest paleae ratio in the genus, being to 2/3 or less of the length of the corolla in the disc florets.

Phenology:—The holotype was collected with florets in March and probably can be found with fruit in April and May; however, fruits were not found in the available specimen.

Taxonomic comments:—During our study at the NY herbarium, the type specimen of this new species was found among unidentified material. This specimen was immediately recognized as a Neurolaena due to the large leaves and paniculiform capitulescence; however, the white corollas of the ray and disc florets and the country of occurrence required further studies to confirm its identity. Due to the presence of opposite leaves at the apex of the branches and the white flowers, both of which are novel traits in Neurolaena , it was first thought to be a species of Alloispermum Willdenow (1807: 139) , which belongs to tribe Millerieae Lindley (1829: 1074) . Subsequent morphological analysis revealed glabrous leaves larger than 15 cm long, pappose tube of ray florets and disc floret tubes longer than 1.75 mm, all of which are characteristics not commonly found in Alloispermum . Only three species of Alloispermum have pappose ray florets: A. insuetum C.F. Fernandez, Urbatsch & G.A. Sullivan (1987: 162–164) , A. longiradiatum ( Urbatsch & Turner 1975: 353–354) Turner (1990a: 135) , and A. palmeri (A. Gray 1887: 430) C.F. Fernandez & Urbatsch ex Turner (1990a: 136) . The most important morphological feature to confirm the taxonomic placement of this species in Neurolaena (rather than Alloispermum ) is the pappus elements as bristles, more than 25 per floret, while Alloispermum species have pappus elements as scales, such as in Calea , less than 25 per floret.

Besides N. brevipalea , three Neurolaena species have radiate capitula (N. ser. Radiatae ): N. cobanensis , N. oaxacana , and N. serboana . Neurolaena curtipalea is hereby placed within this series and can be distinguished from the other species by the opposite (vs. alternate) leaves on the branch apex, camptodromous (vs. penninervous) venation, membranaceous (vs. chartaceous) leaves, ray florets limb 0.5–0.7 mm wide (vs. 1.15–4 mm wide), 25–30 (vs. 40–50) disc florets per capitulum, and disc florets with white (vs. yellow) corolla. Additionally, N. curtipalea occurs in Colombia, while the other three species of N. ser. Radiatae occur in Guatemala, Nicaragua, Costa Rica, and Chiapas and Oaxaca states in Mexico. Thus, N. curtipalea is the first species of the genus that is considered endemic to the Colombian Andes, and consequently the first endemic of South America.

Prior to N. curtipalea , only N. lobata , which is the most widespread and morphologically diverse species of Neurolaena , was known from Colombia. These two species can be easily distinguished by the camptodromous (vs. penninervous) venation, always entire, eglandular (vs. commonly 2-lobed, glandular) leaf blade, radiate (vs. discoid) capitula, 5-seriate (vs. 6-seriate) involucre, 5–10-striate (vs. 2–3-striate) third to fifth series of phyllaries, and disc florets with white (vs. yellow) corolla.

Figures

FIGURE 2. Occurrence map of Neurolaena (Asteraceae, Neurolaeneae) species in the Caribbean and northern South America. Each symbol represents territory and country level species occurrences. CS—Caribbean Sea. Countries and Territories: AB—Antigua and Barbuda, AG—Anguilla, AV—American Virgin Islands, BA—Bahamas, BB—Barbados, BV—British Virgin Islands, CB—Cuba, CI—Cayman Islands, CN—Saint Kitts and Nevis, CO—Colombia, DM—Dominica, DR—Dominican Republic, GD—Guadeloupe, GR—Grenada, GU—Guyana, HA—Haiti, JM—Jamaica, MS—Montserrat, MT—Martinique, PR—Puerto Rico, RR—Roraima state, Brazil, SB—Saba, SL—Saint Lucia, TB—Trinidad and Tobago, TC—Turks and Caicos Islands, VG—Saint Vincent and the Grenadines, VN—Venezuela.

FIGURE 3. Occurrence map of Neurolaena (Asteraceae, Neurolaeneae) species in SouthAmerica.Each point represents state or countries level species occurrences. CS—Caribbean Sea, AO—Atlantic Ocean, PO—Pacific Ocean. Countries and Overseas Territories: AR— Argentina, BO—Bolivia, CO—Colombia, EC—Ecuador, FG—French Guyana, GU—Guyana, GR—Grenada, PE—Peru, PN—Panama, SU—Suriname, VN—Venezuela, TT—Trinidad and Tobago. Brazilian states: RR—Roraima.

FIGURE 4. Neurolaena curtipalea sp. nov. (Asteraceae, Neurolaeneae) A. Flowering branch. B. Alternate leaf. C. Opposite leaf. D. Serrulate margin.E. Capitulum with ray florets removed to show involucre, paleae,and disc floret arrangements.F.First series of phyllaries. G. Second series of phyllaries. H. Third series of phyllaries. I. Fourth series of phyllaries. J. Fifth series of phyllaries. K. Paleae. L. Ray floret with polylength pappus scales. M. Immature ovary with polylength pappus scales. N. Corolla disc. A–N drawn from R. Callejas 6213 (NYBG); A–N: millimeter scale. Illustration by Débora Dalzotto.

FIGURE 5. Geographic occurrence of Neurolaena curtipalea sp. nov. (Asteraceae, Neurolaeneae) in Colombia. CO—Colombia, CS— Caribbean Sea, EC—Ecuador, PN—Panama, PO—Pacific Ocean.