Cyathea fabiolae A. Tejedor, F. Giraldo, Lehnert, and G. Calatayud, 2022

Tejedor, Adrian, Gallego, Luis Fernando Giraldo, Calatayud, Gloria & Lehnert, Marcus, 2022, Cyathea fabiolae (Cyatheaceae, Polypodiopsida), a new scaly tree fern from the northern Andes, Phytotaxa 550 (2), pp. 201-207 : 202-205

Cyathea fabiolae A. Tejedor, F. Giraldo, Lehnert, and G. Calatayud sp. nov.

Type :— PERU. Amazonas: Cenepa, -4.4855, -78.5601, ladera de bosque húmedo. G. Calatayud 6220 (holotype: CUZ!). Figs. 1 , 3 .

A new exindusiate Cyathea similar to Cyathea tortuosa R. C. Moran but differing in its glabrous axes abaxially, and sori arranged in a zigzag pattern.

Trunks erect, to 3 m tall, 4–7 cm diam., without old petiole bases, sparsely covered with nearly concolorous orange-brown scales with very narrow lighter margins, similar to petiole scales; apex hidden between petiole bases, these ascending to patent, forming a loose fascicle. Fronds 5–7 per plant, to 2.5 m long, patent, forming a flat, spreading crown. Petioles to 80 cm long, muricate, spines to 2 mm long, green adaxially, abaxially pale ocher brown, matte, with thin, caducous scurf consisting of appressed, tortuous, tan linear squamules to 1.0 mm long; petioles on each side with a discontinuous line of pale yellowish lenticels to 7.0 × 1.0 mm, scaly only at base. Petiole scales lanceolate, 10.0–15.0 × 2.0–4.0 mm, straight to falcate, shiny, nearly concolorous orange-brown with very narrow translucent pale brown margins, apices attenuate, undulate but not twisted. Laminae to 130 × 100 cm, obovate-elliptic, bipinnatepinnatifid, soft herbaceous, shiny rich green adaxially, paler matte green abaxially; pinna pairs 7–9, basal ones slightly reflexed ca. 1/2 the length of the longest pinnae; apices abruptly reduced. Frond axes (rhachises & costae) inermous, olive green adaxially, slightly darker abaxially, matte to weakly shiny, adaxially pubescent with antrorsely curved to appressed multicellular hairs to 1.0 mm long, abaxially glabrous; costae to 3.0 mm wide. Pinnae to 60 cm long, ± patent to slightly ascending, stalked to 8 mm, alternate, inarticulate, narrowly green-alate. Pinnules to 110 × 26 mm, stalked to 0.5 mm, inarticulate, 2–3 cm between the stalks, lanceate to oblong, bases asymmetrically cuneate, length of proximal basal segments 2/3 that of distal basal segment, tips attenuate with crenulate margins, costules green, glabrous, abaxially with flat lanceolate-attenuate, orange-brown squamules to 2.0 × 0.5–1.0 mm, and appressed, tortuous, tan linear squamules to 1.0 mm long similar to those of young petioles; costules basally with one weakly raised pneumathode (to 2 × 1 mm), dark olive green, inconspicuous. Segments to 14 × 5–6 mm, sessile, adnate, ascending, slightly falcate, tips obtuse, proximal segments opposite, slightly larger than following segments, never remote; sinuses linear acute to 0.2 mm wide, sometimes occluded; margins straight to undulate; veins flat adaxially and abaxially, midveins green dark stramineous to yellowish brown in dry material, glabrous on both sides, with flat lanceolate-attenuate, orange-brown squamules to 2.0 × 0.5–1.0 mm, brown bullate squamules to 0.3 × 0.5 mm and appressed, tortuous, tan linear squamules to 1.0 mm long identical to those of costules; veins ending shortly before the margins, sterile and fertile veins simple or forked. Sori 1.0– 1.2 mm diam., rich orange-brown, basally submarginal to distally subcostal, not parallel to the midvein or margin but slanted, arranged in an attractive zigzag line from base to tip of pinnule, in the fork or on the back of veins; indusia lacking; receptacles globose, 0.3–0.4 mm diam., paraphyses few, shorter than sporangia (0.2 mm long). Spores not examined.

Etymology.— The specific epithet honors Fabiola Areces Berazaín, Cuban botanist who co-found the species.

Additional specimen examined (paratype).— ECUADOR. Napo: Reserva Cocodrilos, Plot 3TE-17, 00°38’31.7”S, 77°48’03.3”W, 1595 m, 17 March 2015, M. Lehnert 3440 (BONN, QCA) .

Distribution & habitat.— Central Ecuador to Northern Peru. In addition to the type collection from Cenepa (Amazonas, Peru) and the paratype from Ecuador, the species is documented through photographs at Tundayme (Zamora-Chinchipe), Cerro Abitagua (Pastaza), and Pacto Sumaco (Napo) ( Fig. 2 ), in the understory of wet lower montane forest, on clayey to sandy soils on scree slopes of Andean tepuis and the main Andean chain. This species is an addition to the already highly rich flora of the northern Andes ( Barthlott et al., 2005), the Cordillera del Cóndor ( Neill, 2005) and the Amotape-Huancabamba Zone (AHZ, Weigend, 2002, 2004), the latter notoriously rich in tree ferns ( Lehnert and Tejedor, 2016 Tejedor and Calatayud, 2017; Tejedor, 2018; Tejedor and Calatayud, 2021). It may be expected in southern, Andean Colombia.

Similar species. — Cyathea fabiolae is morphologically extremely close to the sympatric Cyathea tortuosa but set apart by the combination of subtle but noticeable differences in the fine indument and the preferred temperature zone. Cyathea fabiolae differs from C. tortuosa in its glabrous axes abaxially, more richly colored orange-brown scales, and sori not parallel to either the midveins or the segment margins, so that they appear arranged in a zigzag line from the base to the tip of the pinnule. Cyathea tortuosa , on the other hand, has villous axes abaxially, dull brown petiole scales, and sori parallel to both midveins and segment margins, so that they do not appear to form a continuous zigzag line from base to tip of pinnules ( Fig 3 ). The fine laminar indument in C. fabiolae , especially in plants from higher elevations, appears like a pale dusting, whereas the laminae of C. tortuosa appear more or less clean, with the dark, scaly indument abaxially restricted to the dark costules and midveins and thus inconspicuous.

Cyathea fabiolae also appears to be distributed at higher elevations (1400–1900 m) relative to C. tortuosa (300– 1500 m). The narrow overlap in elevation between the two species covers/comes close to the temperature threshold one experiences commonly at 1000–1200 m in the Andes, where temperatures suddenly drop and daytime mists become regular.

Cyathea cisandina A. Tejedor & G. Calatayud is another sympatric, vagely similar species that grows together with C. fabiolae in the Cordillera del Condor. Cyathea fabiolae differs from C. cisandina in its non-decurrent fronds (basal pinnae ½ the length of medial pinnae) with long petioles (to 80 cm), glabrous, non-scaly axes, thin, papiraceous, slightly translucent orange-brown petiole scales, and subentire segment margins. Cyathea cisandina , in contrast, has strongly decurrent fronds (short basal pinnae 1/5 the length of medial pinnae and often resembling pinnules), shorter petioles (to 15 cm), hirsute axes with stiff spreading reddish hairs interspersed with erect lanceate, brown scales, thick, opaque, dull brown petiole scales, and strongly crenate segment margins.

Cyathea werffii R. C. Moran , is an additional sympatric species, so far known only from small, short-trunked individuals that could be confused with juveniles of C. fabiolae . Cyathea fabiolae can be readily distinguished from C. werffii by its nearly concolorous orange-brown scales and glabrous axes (scales bicolorous with wide whitish margins, and axes sparsely pubescent in C. werffii ). In contrast with C. fabiolae , which is a lower montane species, C. werfii appears to be a lowland–foothill species (300–1200 m).

Cyathea fabiolae is also similar to species of the Cyathea brunnescens (Barrington) R. C. Moran group (including C. brunnescens , Cyathea wendlandii (Kuhn) Domin , Cyathea darienensis R. C. Moran , Cyathea punctata R. C. Moran , Cyathea catenata Lehnert, F. Giraldo and W. Rodriguez , and Cyathea kessleriana, Lehnert, F. Giraldo and A. Tejedor ), distributed on the Pacific slope of the Andes from northern Ecuador to southern Central America (Costa Rica-Chocó Biogeographic region sensu Barthlott et al., 2005) and to which it appears to be closely related. Cyathea fabiolae differs from most species within this group most notably in its clean, indument-free mature axes. Most species in the C. brunnescens group have either persistently hairy ( C. darienensis , C. catenata , and C. kessleriana ) or more densely scurfy axes ( C. brunnescens , and C. wendlandii ). From C. punctata , C. fabiolae differs in its uniformly green lamina abaxially (lamina punctate abaxially in C. punctata , bearing cell clusters, apparently of glandular function).

Finally, C. fabiolae , because of its bright green lamina, relatively long petioles and rich, orange-brown scales, could be confused with small individuals of C. delgadii Pohl ex Sternb. On close inspection, C. fabiolae can be distinguished from C. delgadii by its glabrous lamina and lack of indusium (lamina hairy both adaxially and abaxially, and indusium sphaeropteroid in C. delgadii ).

Together with C. tortuosa , C. werffii , and C. cisandina , C. fabiolae appears to be an Amazonian representative from lowland to lower montane elevations of a species group (that of C. brunnescens ) that is better represented in the trans-Andean lowlands and foothills of the Costa Rica-Chocó biogeographic region. The disjunct nature of this distribution may be related to the severing of continuous lowland wet equatorial forest with the closure of the West Andean Portal (11 Mya, Antonelli et al. 2009) and the uplift of the relatively low Andean ranges that underlie the Amotape-Huancabamba Zone ( Weigend, 2002, 2004) or may be due to dispersal events across the Andean chain. Future dated phylogenies should help shed light on this and other instances of Amazon/Pacific disjunct distributions among tropical Andean tree ferns.

Figures

FIGURE 1. Cyathea fabiolae. A, pinna, silhouette; B, petiole scale; C, fertile pinnule abaxially; D, fertile segment, abaxially, from G. Calatayud 6220.

FIGURE 2. Known localities (black circle, type locality; open circles, localities known from photographic evidence; gray circle, paratype locality) of Cyathea fabiolae along the Amazonian slope of the Andes in Peru and Ecuador. Photographic records: a. Pacto Sumaco, Napo: -0.618, -77.598; b. Mera, Pastaza: -1.438, -78.130; c. Quimi, Morona Santiago: -3.489, -78.417; by Adrian Tejedor, June, 2016.

FIGURE 3. Croziers of A) C. fabiolae, B) C. tortuosa, and C) C. brunnescens. Note lack of villosity, near lack of scurf, and orange-brown scales in C. fabiolae in contrast to C. tortuosa (villous axes abaxially, brown scales) and C. brunnescens (markedly scurfy rachis, brown scales).