Macropholis, Lorence & Wagner & Wood & Smith, 2011

Lorence, David H., Wagner, Warren L., Wood, Kenneth R. & Smith, Alan R., 2011, New pteridophyte species and combinations from the Marquesas Islands, French Polynesia, PhytoKeys 4, pp. 5-51 : 10-12

2. Dryopteris macropholis Lorence & W. L. Wagner sp. nov. Figs 3 4 14B, C, D

Latin.

A ceteris marchinonicis speciebus integra margine maximis usque ad 80 × 14 mm squamis (vel paleis) vestitis rhizomate atque stipitis base, ampla tripinnati-pinnatifida lamina, ultimis usque ad 12-19 × 4-8 mm inferne glabris pinnulis, truncatis vel crenatis, 1/4-2/3 costa dissectis lobis, sparsis parvis castaneis paleis vestita rhachidi, quaque pinnula 1-4 indusiatorum sororum paribus munita, glabro indusio, praecipue differt.

Type.

Marquesas Islands: Ua Huka: Hitikau region, ascended via Matukuoha ridge overlooking Hane, constitutes the summit of the single crater of Ua Huka, 700 m, UTM 0661697-9015668, 5 Dec 2003, K. R. Wood 10489 (Holotype PTBG-041629!, PTBG-041630! [2 sheets]; Isotypes P!, PAP!, US!).

Description.

Terrestrial ferns; rhizomes suberect, 20-25 cm long, 5-7 cm in diameter (to 15 cm including scales), densely clothed with pale brown to reddish brown or dark brown scales; scales of rhizome and base of stipe (10 –)20– 80 × (1 –)2–5– 14 mm, thin, narrowly oblong-elliptic to linear-lanceolate, falcate, usually twisted distally, concolorous, lustrous, medium to dark brown or reddish brown, margins entire, cells narrowly rectangular to linear-fusiform. Fronds clustered, 5-7 per rhizome, erect-arching; stipes (35)49-75 cm long, 4-6 mm in diameter medially, about as long as the blades, adaxially grooved, reddish brown to stramineous, entire length clothed in dense, persistent, spreading, lustrous, light to dark brown or reddish brown, linear-oblong to linear-lanceolate twisted scales to ca. 20 × 3 mm, margins entire or subentire and fringed with short-stipitate glands, bases darkened at point of attachment, mixed with smaller bristlelike and hairlike scales, surfaces bearing short, gland-tipped hairs, scales progressively smaller and finer distally and on rachis, stipes of older fronds punctate with dark scale bases; blades thickly chartaceous, dark above green when fresh, paler beneath, 50-100 × 32-66 cm, ovate-deltate, 3-pinnate to 3-pinnate-pinnatifid at least in lower half, distally mostly 2-pinnate-pinnatifid; rachises stramineous to light brown, densely scaly with persistent medium to dark brown, spreading bristlelike scales to 9 × 1 mm, margins entire or with sparse sessile glands, mixed with short glandular hairs, rachises of older fronds punctuate with dark brown scale bases; pinnae opposite to subopposite, (11 –)13– 20 on a side, spreading, ovate-oblong to linear-oblong, apex acuminate, lowermost pinnae the largest, 20-33 × 11-19 cm, with 11-16 pairs of pinnules, slightly inequilateral, basiscopic basal pinnules 7-10.5 cm long, acroscopic basal pinnules shorter, 4-8.5 cm long, lowermost pinnules usually the largest, distal pinnae stalked 3-6 mm becoming sessile, apices pin natifid; largest ultimate pinnules 12-19 × 4-8 mm, spaced 5-10 mm distant, obtuse to truncate at apices, margins crenate or cut ca. ¼ -2/3 toward costule, adaxially glabrous, abaxially glabrous except for scattered small, spreading, brown linear scales on rachises; veins forking 1-2 times, scarcely visible to visible on both surfaces, depressed adaxially and prominulous abaxially; each fertile pinnule usually with 1-4 pairs of inframedial sori. Sori with indusia 0.4-0.6 mm in diameter, brown, thick, glabrous. Spores dark brown.

Distribution.

Marquesas Islands, known from Nuku Hiva, Ua Huka, Ua Pou, Hiva Oa, and Tahuata.

Ecology.

This new species is rare and localized from ca. 700 to 1150 m elevation. It occurs in transitional mesic to wet forests with Alsophila tahitensis Brack., Hernandia nukuhivensis F. Br., and Sphaeropteris spp.; in wet forests dominated by Crossostylis biflora , Freycinetia spp., Hibiscus tiliaceus L., Metrosideros collina , Pandanus tectorius , and with associates including Fagraea berteroana A. Gray ex Benth., Ficus prolixa G. Forst. var. prolixa; Glochidion (Phyllanthus) marchionicum F. Br., Weinmannia marquesana F. Br. var. marquesana, and Xylosma suaveolens (J. R. Forst. & G. Forst.) G. Forst. subsp. pubigerum Sleumer;in montane wet forests of Metrosideros collina and Weinmannia marquesana var. marquesana; in montane shrublands;and in and summit cloud forests and shrublands with Alsophila tahitensis , Cyrtandra spp., Dicranopteris linearis , Freycinetia spp., Metrosideros collina, Psychotria spp., Sphaeropteris spp., and Vaccinium cereum (L. f.) G. Forst. var. adenandrum (Decne.) F. Br.and diverse pteridophytes. Threats in most areas include human disturbance, feral pigs, and invasive weeds.

Conservation status.

Proposed IUCN Red List Category Endangered (EN): B2a, B2b ( i–iii): B2: total area of occupancy less than 5000 km2 (ca. 904 km2). B1a, severely fragmented; B1b ( i–iii), habitat continuing decline inferred. The suitable habitat for Dryopteris macropholis on Nuku Hiva (ca. 340 km2), Ua Huka (ca. 83 km2), Ua Pou (ca. 105 km2), Hiva Oa (ca. 315 km2), and Tahuata (ca. 61 km2) is restricted to mountain slopes and summits, indicated as an endangered environment that is threatened by human activity (deforestation and fire), feral animals, and invasive plants, reducing the extent of the forest.

Specimens examined.

Marquesas Islands: Nuku Hiva. Toovii, Ooumu area, top of Tapueahu Valley off new road, 8°51'S, 140°19'W, 3500-3700 ft (1067-1128 m), Wood & Perlman 4606 (P, PTBG [2 sheets], US). Route Taiohae–Toovii, branche droite de la haute Taipivai, 8°53'S, 140°8'W, 750 m, Florence 8423 (P [6 sheets]); Piste Nord de Terre Déserte, haute vallée de Tapueahu, 1150 m, 140°11'W, 8°52'S, Florence et al. 9447 (P [3 sheets]). Ua Huka: Hitikau and the Vaikivi summit region, 8°54'S, 139°31'W, 800 m, Wood & Perlman 10761 (PAP, PTBG, US). Ua Pou: forested ridges and slopes to the N and W of Pouakei, 9°23'S, 140°5'W, 2300 ft (701 m), Wood & Perlman 10840 (PAP, PTBG, US); Tekohepu, 2500-3000 ft (762-914 m), 9°24.31'S, 140°4.21'W, Wood 6499 (P [2 sheets], PTBG [2 sheets], US). Hiva Oa: Temetiu, 9°49'S, 139°4'W, 3700 ft (1128 m), Wood 4381 (P, PTBG [2 sheets]); Temetiu region, drainages to southeast of Vaimete et Vaiumioi (source), headwaters of Hanamenu, UTM 0710665-8916125, 3500 ft (1067 m), Wood 10045 (PTBG [5 sheets]); piste de Hanamenu, NW du Mt. Temetiu, 1150 m, 9°48'S, 139°5'W, F lorence & Perlman 9665 (P [4 sheets]). Tahuata: summit ridge near Haaiputeomo, NE of Vaitahu, 9°57.19'S, 139°5.74'W, 2500-2700 ft (762-823 m), Wood 6572 (BISH, P, PAP, PTBG [5 sheets], US).

Discussion.

This remarkable new species resembles Dryopteris macrolepidota Copel. (type from Tahiti), a species distinguished by it massive suberect rhizome with russet scales to 30 × 3 mm, fronds to 160 cm long, stipes to 50-70 cm long, stipes and rachises paleaceous with long, thin russet scales with dark, thickened bases, 3-pinnate subcoriaceous blades to 80 × 40 cm, the abaxial surfaces with scattered thin, linear scales, and supramedial sori. Society Islands collections in the Bishop Museum herbarium identified as Dryopteris dicksonioides (Mett. ex Kuhn) Copel. have massive prostrate to erect rhizomes to 50 cm tall, fronds 80-140 cm long with stipes 60-100 cm long scaly only near the base, stipe scales dark brown and opaque to 20 mm long, rachises with small brown, scattered scales, and 3-pinnate-pinnatifid blades to 80 × 40 cm, the segments thinly chartaceous with linear brown scales on the lower surfaces. Scales of the rhizomes and stipe bases in Dryopteris macropholis are much larger than in the former two species. Palmer (2003) considered Dryopteris dicksonioides synonymous with Dryopteris glabra (Brack.) Kuntze, an exindusiate species endemic to the Hawaiian Islands. However, the type of Dryopteris dicksonioides is from Tahiti and clearly does not represent Dryopteris glabra ( Copeland 1932). This new species seems most closely related to Dryopteris sweetorum , known only from Fatu Hiva, which differs by its rhizome and stipe base scales smaller, lustrous, dark brown, 9-25 × 1-2 mm and its broadly ovate-deltate, 3-pinnate-pinnatifid blades (42 –)62– 93 × (38 –)64– 80 cm, the ultimate segments to 15 × 5 mm, spaced 5-10 mm distant, oblique with tips acute, cut about halfway to the costule, with margins acutely serrate, and the abaxial surfaces and rachises glabrous.

Figures

Figure 3. Dryopteris macropholis Lorence & W. L. Wagner. Frond with A blade and B stipe. Drawn from the type collection (Wood 10489) and field images.

Figure 4. Dryopteris macropholis Lorence & W. L. Wagner. A pinna from near base of lamina, lower surface B lower surface of fertile pinnule showing sori C pinnule with sorus, sporangia, and scales D scale from stipe E part of stipe scale showing detail of cells. Drawn from the type collection (Wood 10489) and field images.

Figure 14. A Blechnum pacificum, habit, habit, fertile and sterile fronds (Fatu Hiva, Lorence 6171) B-D Dryopteris macropholis B frond (Ua Huka, Wood 10489, type) C habit, D rhizome and stipe bases (C, D Hiva Oa, Wood 10045) E Polystichum kenwoodii, rhizome and stipe bases (Hiva Oa, Wood 10232) F Polystichum uahukaense, habit (Ua Huka, Wood 10552).