Danaea polypinna Keskiniva & Tuomisto, 2024

Keskiniva, Venni & Tuomisto, Hanna, 2024, Danaea (Marattiaceae) keeps diversifying, part 1: eighteen new species, Willdenowia 53 (3), pp. 173-228 : 213-215

14. Danaea polypinna Keskiniva & Tuomisto , sp. nov. (D. subg. Holodanaea) – Fig. 27.

Holotype: Costa Rica, Cartago, c. 22 km E of Turrialba, ridge above Platanillo , 1200–1450 m, 22 Aug 1967, Mickel 3420 ( NY!).

Diagnosis — Danaea polypinna is most closely related to D. trichomanoides Spruce ex T. Moore , but is a larger plant (46–72 cm vs 8–16 cm long) with much longer pinnae (6.8–11 cm vs 1.8–2.7 cm). Danaea polypinna co-occurs with D. cuspidopsis Keskiniva & Tuomisto and D. robbinmoranii Keskiniva & Tuomisto but differs in having almost concolorous laminae (vs bicolorous with abaxial side whitish), shorter fertile pinnae (4.8–5.1 cm vs 6.5–11.5 cm) with obtuse to acute apices (vs cuneate to (long-)acuminate), and narrower sterile pinnae (1.2–1.9 cm vs 1.9–2.4 cm). Differs from D. humilis T. Moore in concolorous laminae (vs bicolorous), larger size (sterile leaves 46–72 cm vs 24–42 cm long), and longer (6.8–11 cm vs 2.2–3.3 cm) and wider (1.2–1.9 cm vs 0.7–1.0 cm) pinnae. Differs from D. chococola Christenh. in longer (6.8–11 cm vs 3.0– 4.5 cm) and wider (1.2–1.9 cm vs 0.7– 1.2 cm) pinnae, thinner lamina texture, and brown colour when preserved with alcohol before drying (vs greyish). Genetically unique among Danaea in having a T (vs A or C) at position 529 of rpl32 reference sequence and differing from all other species of D. subg. Holodanaea in having an A (vs C) at position 632 of rpl32 reference sequence.

Description — Rhizomes radial, probably erect but not confirmed, 1.0– 1.5 cm in diam., to 10 cm long. Sterile leaves 46–72 cm long; petioles 14–38 cm long, with 1–3 nodes, winged, winged only in distal part or not winged; laminae 30–40 × 12–17 cm, parallel-sided, paripinnate, 14–21 pinna-pairs, proximal pinna-pair reduced or more distant and smaller, medial pinnae 1.4–2.4 cm apart, almost concolorous, dark green or brown adaxially, laminar texture thin, rachises winged at least distally, wings to 0.3–1.5 mm wide, costae usually covered in reddish brown scales; largest lateral pinnae 6.8–11 × 1.2–1.9 cm, 5.1–6.2 times as long as wide without apex, parallel-sided, perpendicular to rachises or slightly ascending, bases asymmetrical (obtuse proximally, acute distally), apices 0.6–1.6 cm long, acuminate to attenuate, margins of apices serrate to serrulate; veins 17–25 per cm, mostly simple, sometimes variably simple and paired at costae. Fertile leaves 61 cm long; petioles 23 cm long, 0–1 node; laminae 23–38 × 7–13 cm, 15–22 pinna-pairs, paripinnate, parallel-sided; largest lateral pinnae 4.8–5.1 × 0.4–0.6 cm, linear-oblong, perpendicular to rachises or slightly ascending, bases obtuse, apices obtuse or acute. Juveniles known from one plant growing from bud of an adult specimen, this imparipinnate, 7 pinna-pairs when 8 cm long, laminae parallel-sided, terminal pinnae lanceolate, lateral pinnae parallel-sided, bases asymmetrical, apices acute.

Distribution and habitat — Known from central Panama (Chiriqui and Bocas del Toro) and Costa Rica (Limón and Cartago), from 850–1450 m. One site described as very moist upland forest. Fig. 8.

Conservation status — We place Danaea polypinna in the Near Threatened (NT) category ( IUCN 2012). It has an Area of occupancy of 28 km 2 and an Extent of occurrence of 4184 km 2, which correspond to the EN category. It is known from only 7 collections despite considerable collection efforts in Costa Rica and Panama; this suggests that it is rare. It has been found growing in three protected areas (Reserva Forestal de Fortuna in Panama, Parque Internacional La Amistad, and Parque Nacional Tapantí in Costa Rica), and there appears to be no imminent threat to all its subpopulations.

Etymology — Named for the large number of pinna-pairs.

Remarks — Danaea polypinna is a rather small species with short, sausage-like fertile pinnae that are common in small species of D. subg. Holodanaea. It is characterized by many short and narrow sterile pinnae with abruptly tapering apices and rather concolorous laminae that dry to a dark brown or dark green colour, costae typically covered in reddish brown scales, and radial, probably erect rhizomes.

Danaea polypinna co-occurs with D. cuspidopsis and D. robbinmoranii , but differs in having almost concolorous laminae (vs bicolorous and clearly whitish abaxially), shorter fertile pinnae (4.8–5.1 cm vs 6.5–12 cm) with obtuse to acute apices (vs cuneate to (long-)acuminate), generally smaller size (sterile leaves 46–72 cm vs 54–120 cm long), and pinnae that are narrower (1.2–1.9 cm vs 1.9–2.4 cm) and often shorter (6.8–11 cm vs 8.0– 16 cm). In addition, D. polypinna has generally more pinna-pairs than D. robbinmoranii (14–21 vs 7–16).

Out of the sequenced species, Danaea polypinna is most closely related to the Amazonian D. trichomanoides . However, D. polypinna is a much larger plant (46–72 cm vs 8–16 cm long) with longer pinnae (6.8–11 cm vs 1.8–2.7 cm).

Danaea polypinna is similar to D. humilis and D. chococola in having many short and narrow pinnae with short apices, but is larger (sterile leaves 46–72 cm long vs 38–48 in D. chococola , 27–42 cm in D. humilis ) and its pinnae are longer (6.8–11 cm vs 3.0– 4.5 cm in D. chococola , 2.2–3.3 cm in D. humilis ) and wider (1.2–1.9 cm vs 0.7–1.2 cm in D. chococola , 0.7–1.0 in D. humilis ). Furthermore, D. humilis has bicolorous laminae (vs concolorous) and D. chococola has a greyish sheen (vs dark brown).

Danaea wendlandii and D. gracilis are clearly small- er plants (sterile leaves max. 32 cm vs 46–72 cm long) with smaller pinnae (max. 5.9 cm long and 1.2 cm wide vs 6.8–11 × 1.2–1.9 cm).

Danaea polypinna is very similar in size and shape to D. ypori Christenh. from French Guiana but differs in having almost concolorous pinnae (vs bicolorous) that are mostly parallel-sided (vs often oblanceolate), thinner laminar texture, and by most likely having erect rhizomes (vs creeping-ascending). Danaea polypinna also resembles D. inaequilatera but differs in having narrower fertile pinnae (0.4–0.6 cm vs 0.8–1.3 cm), sterile laminae being thinner in texture and darker in colour (dark brown vs (light greyish) green), and terminal pinnae almost always being replaced by a bud (vs terminal pinnae usually present).

Additional specimens examined — COSTA RICA: LIMÓN: Cantón de Talamanca, Bratsi, Amubri , Alto Lari , Kivut , upper basin of Río Dapari , 09°24'N, 83°05'W, 1200 m, 9 Mar 1992, Herrera 5250 (F!) ; CARTAGO: Turrialba, Tayutic, Jicotea , Finca La Pradera , going up Fila toward San Antonio , 09°47'N, 83°33'W, 1400 m, 14 Jun 1995, Herrera 7873 (F!, K-2!); Orosi, P. N. Tapantí, Oropéndola trail and banks of Río Orosi , 09°45'N, 83°47'W, 1230 m, 21 Nov 2004, Rojas 6272 (MO!) ; ALAJUELA: Along Río La Balsa about 23 km NE of San Ramón, 850 m, 29 Dec 1974, Taylor 17805 (BRIT!) . — PANAMA: BOCAS DEL TORO: Bosque Protector Palo seco, El Verrugoso trail, entering through farm of Sr. Desiderio Meneses, 08°47'N, 82°11'W, 972 m, 7 Feb 2013, Aranda 4432 (MO!, PMA!) ; CHIRIQUI: Distrito Boquete, Fortuna Dam site, 1100 m, 8 Feb 1985, van der Werff 6757 (GH!, MO, UC!) .