Danaea peruviana Keskiniva & Tuomisto, 2024

Keskiniva, Venni & Tuomisto, Hanna, 2024, Danaea (Marattiaceae) keeps diversifying, part 1: eighteen new species, Willdenowia 53 (3), pp. 173-228 : 211-213

13. Danaea peruviana Keskiniva & Tuomisto , sp. nov. (D. subg. Holodanaea) – Fig. 26.

Holotype: Peru, San Martín, Rioja, Alto Mayo Protect- ed Forest (BPAM) , 06°06'S, 77°18'W, 1424–1441 m, 5 Dec 2015, Suominen 362 ( TUR! (mounted on 2 sheets: 616256, 616257); isotype: USM).

Diagnosis — Morphologically most similar to Danaea mazeana Underw. , but differs in having strictly erect rhizomes (vs creeping), generally fewer nodes on petioles (0–1(–2) vs 2–3), and straight (vs usually slightly falcate) lateral pinnae. Similar to and possibly co-occurring with D. excurrens Rosenst. and D. andina Keskiniva & Tuomisto , but differing in generally larger size (sterile leaves 64–94 cm long vs 35–62 cm in D. excurrens and 46–71 cm in D. andina ); rhizomes erect (vs often creeping or ascending) and longer (to 40 cm vs to 20 cm long); pinna apices generally longer (1.5–4.0 cm vs 0.5– 1.6 cm) and often rather wide (vs narrow). Also differs from D. andina in having longer pinnae (13–15 cm vs 4.5–13 cm). Only observed fertile leaf of D. peruviana is unique in D. subg. Holodanaea in having relatively long and broad fertile pinnae (c. 12 × 1.4 cm) with synangia widely spaced and sterile zones at pinna margins and around midvein.

Description — Rhizomes erect and radial, 1.0– 2.5 cm in diam., to 40 cm long. Sterile leaves 64–94 cm long; petioles 28–43 cm long, with 0–1(–2) nodes, not winged; laminae 35–66 × 23–27 cm, (long-)obovate to (long-)lanceolate, imparipinnate, 11–16 pinna-pairs, if no node then proximal pinnae small, elliptic and distant, medial pinnae 1.8–2.5 cm apart, bicolorous, dark grey-brown adaxially, light grey-brown abaxially, texture thin, rachises winged in distal part of lamina, wings to 0.2–1.0 mm wide; terminal pinnae 9.5–13 × 1.5–2.0 cm, lanceolate to oblong, bases acute, apices 1.5–2.9 cm long, (long-)acuminate to caudate, margins of apices (deeply) serrate; largest lateral pinnae 13–15 × 1.4–2.2 cm, 5.0–8.6 times as long as wide without apex, usually parallel-sided, perpendicular to rachises or slightly ascending, bases asymmetrical (obtuse to auriculate proximally, acute to obtuse distally), apices 1.5–4.0 cm long, (long-)acuminate or caudate, sometimes rather wide, margins of apices (deeply) serrate; veins 12–14 per cm, mostly paired at costae, sometimes many simple. Fertile leaves 62 cm long; petioles 29 cm long, 1 node; laminae 33 × 25 cm, imparipinnate, obovate, 13 pinna-pairs; terminal pinnae 1.7 cm wide; largest lateral pinnae c. 12 × 1.4 cm, long-lanceolate, perpendicular to rachis, bases symmetrical, truncate (or asymmetrical, obtuse to auriculate proximally, acute to obtuse distally), apices 2 cm long, long-acuminate to cuneate, margins of apices serrate. Juveniles not known.

Distribution and habitat — Known only from a small area on the eastern slopes of the Andes in Peru (San Martín), from 1200–1500 m. Fig. 8.

Conservation status — We place Danaea peruviana in the Endangered (EN B1ab(iii)+2ab(iii)) category ( IUCN 2012). It has an Extent of occurrence of 45 km 2 which corresponds to the Critically Endangered (CR) category and an Area of occupancy of 16 km 2 which corresponds to the Endangered (EN) category. It is known from only 9 collections, one of which was collected in a selectively logged location and the others from a single reserve (Bosque de Protección Alto Mayo in Peru). The species seems to be endemic to a small area where the extent and quality of suitable habitat is inferred to be in continuous decline from deforestation.

Etymology — This species has been found only in Peru.

Remarks — Danaea peruviana is an intermediate-sized species of the complex that was previously referred to D. moritziana . It has erect rhizomes and long, parallel-sided pinnae that dry to a dark greyish brown colour and have rather gradually tapering and often relatively broad apices. The fertile pinnae appear unique within D. subg. Holodanaea in that the synangia are widely spaced, and there is a sterile zone at their margins and around the midrib (vs synangia tightly packed and no sterile zones), which makes the fertile pinnae unusually long and broad. This is an excellent diagnostic character if it is consistent, but we have seen only one fertile leaf, so the possibility of aberrant growth in this individual cannot be ruled out.

In general appearance, including the relatively broad pinna apices, Danaea peruviana is most similar to D. mazeana , which is endemic to the Lesser Antilles and has creeping radial rhizomes (vs erect), more nodes on the petioles (2–3 vs 0–1(–2)), and usually slightly falcate (vs straight) lateral pinnae.

Danaea peruviana is most easily confused with D. excurrens and D. andina , which may also grow in the Peruvian Andes. Danaea peruviana is larger than the other two (sterile leaves 64–94 cm vs 35–62 cm long in D. excurrens and 46–71 cm in D. andina ), with rhizomes that are clearly erect (vs creeping or ascending to erect) and longer (to 40 cm vs to 10–21 cm long) and pinnae that are longer than in D. andina (13–15 cm vs 4.5–13 cm long) and have longer but broader apices than either of the other two species (1.5–4.0 cm vs 0.5–1.6 cm long). In addition, D. peruviana dries to a dark greyish brown and is only slightly paler abaxially (vs green to light brown with abaxial side whitish in D. excurrens and D. andina ).

Danaea betancurii also occurs in Peru, but D. peruviana has generally fewer pinna-pairs (11–16 vs 13–20) that can be wider (1.4–2.2 vs 0.9–2.0 cm wide), are usually longer (minimum 13.1 cm vs 7.4 cm long), and have generally longer apices (1.5–4.0 cm vs 0.9–2.0 cm long). In addition, D. betancurii generally has more nodes on the petioles (1–4 vs 0–1(–2)) and can also have creeping to ascending rhizomes (vs always erect) that remain shorter (to 14 vs to 40 cm long).

Additional specimens examined — PERU: SAN MARTÍN: Rioja, 05°59'S 77°22'W, 1270–1295 m, 29 Jul 2014, Suominen 148 (TUR!); Rioja, Alto Mayo Protected Forest (BPAM), 05°58'S 77°24'W, 1374–1446 m, 10 Jun 2015, Suominen 207 (TUR!, USM); Rioja, BPAM, 05°58'S 77°24'W, 1373–1446 m, 11 Jun 2015, Suominen 242 (TUR-2!, USM-2); Rioja, BPAM, 05°55'S 77°28'W, 1292–1358 m, 16 Jun 2015, Suominen 260 (TUR-2!, USM-2); Rioja, BPAM, 05°55'S 77°28'W, 1292–1358 m, 16 Jun 2015, Suominen 269 (TUR-2!, USM-2); Rioja, BPAM, 05°55'S 77°28'W, 1292–1358 m, 17 Jun 2015, Suominen 282 (TUR!, USM); Rioja, BPAM, 06°06'S 77°18'W, 1424–1441 m, 4 Jul 2015, Suominen 357 (TUR- 3!, USM-2); Rioja, BPAM, 06°06'S 77°18'W, 1424–1441 m, 5 Jul 2015, Suominen 373 (TUR!, USM) .